Methods for selecting ESP for an oil well. Selection of the optimal mode of wells operated by electric centrifugal pump installations Selection of ESP calculations
The selection of an ESP for a well is carried out through calculations during commissioning from drilling and transfer to the furnace. production, optimization and intensification according to the methodology adopted at NGDU, which does not contradict the specifications for the operation of ESP.
Calculations are based on information available at NGDU:
productivity coefficient of a given well (based on the results of hydrodynamic studies of the well);
inclinometry data;
gas factor;
pressure –
o reservoir,
o saturation pressure;
water cut of produced products;
concentration of carried out particles.
The leading geologist of the oil production department is responsible for the accuracy of this information.
When using RD 39-0147276-029, VNII-1986 in the calculations of “Technology for checking the production casing and using ESP in directional wells”, for wells with a rate of curvature in the ESP suspension zone of more than 3 minutes per 10 meters, it is necessary to put a mark on the application of this technique in the passport form.
In the selection process, it is necessary to be guided by the methodology adopted at NGDU. In this case, the maximum free gas content at the pump inlet should not exceed 25% for installations without gas separators. In case a significant removal of fur is expected from the well. impurities or salt deposits in the pump, it is prohibited to drain the ESP without a sludge trap.
Selection results:
estimated daily flow rate,
pump pressure,
internal minimum diameter of the production string,
depth of descent,
calculated dynamic level,
maximum rate of curvature gain in the descent zone and in the ESP suspension section;
special operating conditions:
high fluid temperature in the suspension area,
calculated percentage of free gas at the pump intake,
presence of carbon dioxide and hydrogen sulfide in the pumped liquid entered in the passport form.
Dangerous zones in the column, where the rate of increase in curvature exceeds the permissible norms (more than 1.5° per 10 meters), are entered in the passport form when filling out an application for EPU-SERVICE.
The determination of the test gauge and its length is made on the basis of tables No. 1 and No. 2.
Table No. 1
SUBMERSIBLE ELECTRIC MOTORS
|
Engine's type |
Length with waterproofing, mm |
Weight (with water protection), kg |
Nar. dia. including cable, mm |
|
|
PEDS-125-117 | ||||
Length from flange to flange:
o pump module 3 - 3365 mm;
o pump module 4 - 4365 mm;
o pump module 5 - 5365 mm.
All types of pumps can be made:
with a wafer connection of sections (yoke connection);
wear-corrosion-resistant (ETsNMK-ETSND);
with a receiving mesh and a fishing head in sections.
When selecting an ESP for a well, it is necessary to take into account the decrease in the power of the submersible electric motor due to an increase in the temperature of the surrounding formation fluid, in accordance with the current specifications of the manufacturing plants.
After receiving the results of selecting an ESP for the well, EPU-Service accepts the application for installation of this ESP and determines the type of engine, hydraulic protection, cable, gas separator and ground equipment required for the configuration in accordance with the current specifications and the ESP operating manual. The length of the heat-resistant cable line extension is determined by ESP specialists at the NGDU and is entered into the passport form. Information on the type of component equipment for wells where additional preparation work (templating) must be carried out is provided by EPU-Service to TTND NGDU before the start of work.
Well preparation is carried out in accordance with the “Work Plan” issued by the production department, taking into account the following requirements, regardless of whether they are included in the work plan:
In accordance with the project for the arrangement of well clusters approved for this oil and gas department, at a distance of at least 25 m from the well, a site must be prepared for the placement of ground electrical equipment (GEO) ESP with a ground loop connected by a metal conductor to the ground loop of the transformer substation (TP 6/0.4 ) and well conductor. The service of the chief power engineer of the NGDU must submit to "EPU-Service" a report on measuring the resistance of the grounding loop before the delivery of submersible equipment to the pad, and during the operation of the ESP, carry out similar measurements and submit reports to the EPU at least once a year. Conductors must be welded to the grounding loop in accordance with the PUE for grounding control stations (CS) and transformers (TMPN) of the ESP. The site for the placement of NEO must be located in horizontal plane, protected from flooding during the flood period. The entrances to the site should allow easy installation and dismantling of the NEO using a Fiskars unit or a truck crane. The head of the CDNG is responsible for the good condition of the sites.
A terminal box (ball screw) should be installed 10-25 m from the wellhead. The power cables of the external connections cabinet (ECC) to the control station (CS) of the ESP and from the transformer substation (TS) 6/0.4 to the CS are laid by NGDU. The connection of cables to the control station (CS), ball screws and grounding of ground equipment is carried out by EPU-Service. Cables must be laid along an overpass or buried at least 0.5 m into the ground. The person responsible for the normal condition of the cable racks is the foreman of the TsDNG production team.
It is prohibited to operate ESPs that do not comply with the requirements of the PUE and TB of sites for the placement of electrical equipment, cable racks, ball screws and grounding. The head of the EPU-Service rental shop is responsible for the implementation of this clause.
P.S. Additionally, the answer to the question “Production Basics Course” section ESP.
Ministry of Education and Science of the Russian Federation
Federal State Budgetary Educational Institution
higher professional education
"Sakhalin State University"
Technical Oil and Gas Institute
Department of Oil and Gas Business
Course work
Calculation of the installation of an electric centrifugal pump for well No. 96 of the Odoptu-Susha field
Larionov D.F.
Scientific director
Novikov D.G.
Yuzhno-Sakhalinsk 2015
Introduction
Chapter 1. Electrical installations centrifugal pumps
1 General installation diagram of a submersible electric centrifugal pump
2 Electric centrifugal pump (ECP)
3 Gas separator
1.4 Water protection and submersible electric motor (SEM)
5 Telemetry system (TMS)
1.6 Drain valve and check valve
8 Control station and transformer
Chapter 2. Calculation part
1 Initial data for calculating the installation of an electric centrifugal pump for well No. 96 of the Odoptu-Susha field
2 Selection of equipment and selection of ENC installation units
3 Checking the diametrical dimensions of submersible equipment
4 Checking the parameters of the transformer and control station
Chapter 3. Safety precautions
1 Occupational safety during operation of borehole centrifugal pump installations
Conclusion
List of sources used
Introduction
The operation of wells using submersible centrifugal pumps (ESP) is currently the main method of oil production in Russia. These installations extract about two-thirds of the total annual oil production in our country to the surface.
Electric centrifugal well pumps (ESP) belong to the class of dynamic vane pumps, characterized by higher flow rates and lower pressures compared to positive displacement pumps.
The supply range of downhole electric centrifugal pumps is from 10 to 1000 m 3 /day or more, the pressure is up to 3500 m. In the supply range of over 80 m 3 /day, the ESP has the highest efficiency among all mechanized oil production methods. In the flow range from 50 to 300 m 3 /day, the pump efficiency exceeds 40%.
The selection of an ESP for a well at the modern level involves performing relatively labor-intensive and cumbersome calculations and is carried out using a computer.
One of the most important conditions for the effective use of ESPs is the correct selection of ESPs for the well, that is, the choice for each specific well of such interdependent standard sizes of a pump, an electric motor with hydraulic protection, a cable, a transformer, lifting pipes from the existing equipment fleet, and such a depth of lowering the pump into the well, which will ensure the development of the well and the technological standard for fluid withdrawal (nominal flow rate) from it in the steady-state operating mode of the well-ESP system at the lowest cost.
The selection of an ESP for a well at the modern level involves performing relatively labor-intensive and cumbersome calculations and is carried out using a computer.
Chapter 1. Electric centrifugal pump installations
1 General scheme installation of a submersible electric centrifugal pump
To date, a large number of different schemes and modifications of ESP installations have been proposed. Figure 1 shows one of the diagrams for equipping a production well with the installation of a submersible centrifugal electric pump.
Figure 1 - Installation diagram of a submersible centrifugal pump in a well
Submersible electric motor (SEM) 2, protector 3, receiving screen 4 with gas separator 5, pump 6, fishing head 7, pump check valve 8, drain valve 9, tubing string 10, elbow 11, flow line 12, wellhead check valve 13, pressure gauges 14 and 16, wellhead fittings 15, cable line 17, connecting ventilation box 18, control station 19, transformer 20, dynamic fluid level in the well 21, belts 22 for attaching the cable line to the tubing and pumping unit and operational well string 23.
When the installation is operating, pump 6 pumps liquid from the well to the surface through tubing pipes 10. Pump 6 is driven by a submersible electric motor 2, power to which is supplied from the surface via cable 17. Motor 2 is cooled by the flow of well products. Ground-based electrical equipment - a control station 19 with a transformer 20 - is designed to convert the field power supply voltage to a value that provides the optimal voltage at the input to the electric motor 2, taking into account losses in the cable 17, as well as to control the operation of the submersible unit and protect it during abnormal conditions.
Acceptable according to domestic standards technical specifications The maximum free gas content at the pump inlet is 25%. If there is a gas separator at the ESP intake, the permissible gas content increases to 55%. Foreign ESP manufacturers recommend using gas separators in all cases where the input gas content is more than 10%.
2 Electric centrifugal pump (ECP)
The pump module section (Figure 2) consists of a housing 1, a shaft 2, stage packages (3 impellers and 4 guide vanes), an upper bearing 5, a lower bearing 6, an upper axial support 7, a head 8, a base 9, two 10 ribs (serve to protect the cable from mechanical damage) and rubber rings 11, 12, 13.
Figure 2 - Diagram of the pump section module
Frame; 2 - shaft; 3 - working wheel; 4 - guiding apparatus;
Upper bearing; 6 - lower bearing; 7 - upper axial support; 8 - head; 9 - base; 10 - rib; 11, 12, 13 - rubber rings.
The impellers move freely along the shaft in the axial direction and are limited in movement by the lower and upper guide vanes. The axial force from the impeller is transmitted to the lower textolite ring and then to the guide vane collar. Partial axial force is transferred to the shaft due to friction of the wheel on the shaft or sticking of the wheel to the shaft due to the deposition of salts in the gap or corrosion of metals. Torque is transmitted from the shaft to the wheels by a brass key that fits into the groove of the impeller. The key is located along the entire length of the wheel assembly and consists of segments 400 - 1000 mm long.
The guide vanes are articulated with each other along the peripheral parts, in the lower part of the housing they all rest on the lower bearing 6 (Figure 2) and the base 9, and from above through the upper bearing housing they are clamped into the housing.
The impellers and guide vanes of standard pumps are made of modified gray cast iron and radiation-modified polyamide; corrosion-resistant pumps are made of modified cast iron TsN16D71KhSh of the “niresist” type.
The shafts of section modules and input modules for pumps of standard design are made of combined corrosion-resistant high-strength steel OZH14N7V and are marked “NZh” at the end; for pumps with increased corrosion resistance - from calibrated rods made of N65D29YUT-ISH-K-Monel alloy and are marked at the ends "M".
The shafts of the module sections of all groups of pumps, which have the same body lengths of 3, 4 and 5 m, are unified. The connection of the shafts of the section modules with each other, the section module with the input module shaft (or gas separator shaft), and the input module shaft with the engine hydraulic protection shaft is carried out using splined couplings. The connection between the modules and the input module to the motor is flanged. The connections (except for the connection of the input module to the engine and the input module to the gas separator) are sealed with rubber rings.
3 Gas separator
To pump out formation fluid containing more than 25% (up to 55%) by volume of free gas at the pump inlet module grid, a pumping module - gas separator is connected to the pump (Figure 3).
Figure 3 - diagram of the gas separator assembly
Head; 2 - sub; 3 - separator; 4 - body; 5 - shaft; 6 - grate; 7 - guide vane; 8 - impeller; 9 - auger; 10 - bearing; 11 - base.
The gas separator is installed between the input module and the section module. The most effective gas separators are of the centrifugal type, in which the phases are separated in a field of centrifugal forces. In this case, the liquid is concentrated in the peripheral part, and the gas is concentrated in the central part of the gas separator and is released into the annulus. Gas separators of the series: modular pump-gas separator (MPG) have a maximum flow of 250¸ 500 m 3 /day, a separation coefficient of 90%, a weight from 26 to 42 kg.
4 Water protection and submersible electric motor (SEM)
The engine of a submersible pumping unit consists of an electric motor and hydraulic protection. Electric motors (Figure 4) are submersible three-phase, short-circuited, two-pole, oil-filled, conventional and corrosion-resistant designs of the unified PEDU series and in the conventional design of the PED modernization series L. Hydrostatic pressure in the operating area is no more than 20 MPa. Rated power from 16 to 360 kW, rated voltage 530-2300 V, rated current 26-122.5A.
Figure 4 - Electric motor assembly diagram of the PEDU series
Thrust bearing; 6 - cable entry cover; 7 - plug; 8 - cable entry block; 9 - rotor; 10 - stator; 11 - filter; 12 - base.
Hydraulic protection (Figure 5) of SEM motors is designed to prevent formation fluid from penetrating into the internal cavity of the electric motor, compensating for changes in the volume of oil in the internal cavity from the temperature of the electric motor and transmitting torque from the electric motor shaft to the pump shaft.
The hydraulic protection consists of either one protector or a protector and a compensator. There may be three options for hydraulic protection.
Figure 5 - Diagram of the hydraulic protection unit:
a - open type; b - closed type. A - upper chamber; B - lower chamber; 1 - head; 2 - mechanical seal; 3 - upper nipple; 4 - body; 5 - middle nipple; 6 - shaft; 7 - lower nipple; 8 - base; 9 - connecting tube; 10 - aperture.
The first: consists of protectors P92, PK92 and P114 (open type) from two chambers. Upper chamber filled with a heavy barrier liquid (density up to 2 g/cm 3, not mixed with formation fluid and oil), the lower one is filled with oil, the same as the cavity of the electric motor. The cameras are connected by a tube. Changes in the volume of liquid dielectric in the engine are compensated by transferring the barrier liquid in the hydraulic protection from one chamber to another.
The second: consists of protectors P92D, PK92D and P114D (closed type), which use rubber diaphragms, their elasticity compensates for changes in the volume of liquid dielectric in the engine.
Third: hydraulic protection 1G51M and 1G62 consists of a protector located above the electric motor and a compensator attached to the bottom of the electric motor.
The mechanical seal system provides protection against formation fluid ingress along the shaft into the electric motor. Transmitted power of hydraulic protection 125¸ 250 kW, weight 53¸ 59 kg.
5 Telemetry system (TMS)
The telemetry system (TMS) is designed to monitor certain technological parameters of wells equipped with ESP (pressure, temperature, vibration) and protect submersible units from abnormal operating conditions (overheating of the electric motor or a decrease in fluid pressure at the pump intake below the permissible level).
The TMS system consists of a downhole transducer that transforms pressure and temperature into a frequency-manipulated electrical signal, and a surface device that performs the functions of a power supply, an amplifier-signal conditioner and a device for controlling the operating mode of a submersible electric pump in terms of pressure and temperature.
The downhole pressure and temperature transducer (PDT) is made in the form of a sealed cylindrical container placed in the lower part of the electric motor and connected to the zero point of its stator winding.
A ground-based device installed in the ShGS complete device provides the generation of signals to turn it off and turn off the pump based on pressure and temperature.
The power supply network of the submersible electric motor is used as a communication line and power supply for the submersible sensor (DS).
6 Drain valve and check valve
The drain valve (Figure 7) is designed to drain liquid from the tubing when lifting the ESP from the well.
The drain valve consists of a body 1 with a fitting 2 screwed into it, which is sealed with a rubber ring 3.
Before lifting the ESP from the well, the end of the fitting, located in the internal cavity of the valve, is knocked down (broken off) by dropping a special tool into the well, and the liquid from the tubing string flows through the hole in the fitting into the pipe space.
The drain valve is installed between the check valve and the tubing string.
During transportation, the drain valve is closed with covers 4, 5.
Figure 7 - Drain valve assembly diagram
Frame; 2 - fitting; 3 - rubber ring; 4.5 - covers.
Check Valve.
The check valve (Figure 8) is designed to prevent reverse (turbine) rotation of the pump impellers under the influence of the liquid column in the pressure pipeline when the pump is stopped and to facilitate subsequent startup; it is used for pressure testing of the tubing string after lowering the installation into the well.
The check valve consists of a body 1, a rubber-coated seat 2, on which a plate 3 rests. The plate has the ability to move axially in the guide sleeve 4.
Under the influence of the flow of pumped liquid, the plate rises, thereby opening the valve. When the pump stops, the plate lowers onto the seat under the influence of the liquid column in the pressure pipeline and the valve closes. The check valve is installed between the upper section of the pump and the drain valve. During transportation, the check valve is closed with covers 5 and 6.
Figure 8 - Check valve assembly diagram
7 Cable
The cable line is a cable assembly wound on a cable drum.
The cable assembly consists of a main cable - round (Figure 9a) (PKBK) cable, polyethylene insulation, armored, round or flat - polyethylene armored flat cable (KBPP) (Figure 9b), attached to it a flat cable with a cable entry coupling (extension cord) with coupling).
Figure 9 - Cables
a - round, b - flat.
Core, 2 - insulation, 3 - shell, 4 - pillow, 5 - armor.
The cable consists of three cores, each of which has an insulation layer and a sheath; cushions made of rubberized fabric and armor. Three insulated cores of a round cable are twisted along a helical line, and the cores of a flat cable are laid parallel in one row.
The KFSB cable with fluoroplastic insulation is designed for operation at ambient temperatures up to + 160˚C.
The cable assembly has a unified cable entry coupling K38 (K46) of the round type. The insulated conductors of the flat cable are hermetically sealed in the metal housing of the coupling using a rubber seal.
Plug lugs are attached to the conductive conductors.
The round cable has a diameter from 25 to 44 mm. Flat cable sizes from 10.1x25.7 to 19.7x52.3 mm. Nominal construction length 850, 1000¸ 1800 m.
1.8 Control station and transformer
Complete devices of the control station and transformer provide switching on and off of submersible motors, remote control from the control center and program control, operation in manual and automatic modes, shutdown in case of overload and deviation of the supply voltage above 10% or below 15% of the nominal, current control and voltage, as well as external light signaling of emergency shutdown (including with a built-in thermometric system).
The integrated transformer substation for submersible pumps (CTPPS) is designed to supply electricity and protect electric motors of submersible pumps from single wells with a capacity of 16-125 kW inclusive.
Nominal high voltage 6 or 10 kV, medium voltage regulation limits from 1208 to 444 V (transformer TMPN100) and from 2406 to 1652 V (TMPN160). Weight with transformer 2705 kg.
Chapter 2. Calculation part
1 Initial data for calculating the installation of an electric centrifugal pump for well No. 96 of the Odoptu-Susha field
When selecting an ESP, the following initial data are required:
Density, kg/m 3:
separated oil -850
gas under normal conditions -1
Viscosity coefficient, m 2 /s∙10-5
oil - 5.1
Planned well production, m 3 /day - 120
Water cut of reservoir products, fractions of a unit - 0.5
Gas factor, m 3 /m 3 - 42
Volumetric coefficient of oil, units. - 1.23
Depth of formation (perforation holes), m - 2250
Reservoir pressure MPa - 11.2
Saturation pressure, MPa - 5
Reservoir temperature and temperature gradient, ºС - 50, 0.02
Productivity coefficient, m 3 / MPa - 21
Buffer (annulus) pressure, MPa - 1.1/1.1
Casing dimensions, mm - 130
Effective viscosity of the mixture, m 2 /s*10-5-4.1
2.2 Selection of equipment and selection of ENC installation units
The selection of an ESP installation is carried out in the following sequence:
The density of the mixture in the section “bottom of the well - pump intake” is determined, taking into account the simplifications:
Рcm = (1- Г) + рг Г, (3.1)
where ρi is the density of separated oil, kg/cub.m;
ρв - density of formation water;
ρg - gas density under standard conditions;
G - current volumetric gas content; - water cut of formation fluid.
ρcm = (1-0.18)+1 0.18=771 kg/m 3
The bottomhole pressure at which the specified well flow rate is ensured is determined:
Rzab = Rpl-Q / Kprod, (3.2)
where Rpl - reservoir pressure, MPa; - specified well flow rate, m 3 / day;
Kprod - well productivity coefficient, m 3 /MPa.
Rzab = 11.2-120/21=5.49 MPa=5.5·106 Pa
The depth of the dynamic level at a given fluid flow rate is determined:
NDIN = Lskw - Rzab / Рсм g. (3.3)
where: Lwell is the depth of the formation, m
Ndin = 2250-5.5 106/771 9.8 = 1523 m
The pump inlet pressure is determined at which the gas content at the pump inlet does not exceed the maximum permissible for a given region and a given type of pump (for example - G = 0.15):
Rpr = (1 - G) R US, (3.4)
(with the exponent depending on the degassing of the formation fluid t = 1.0), where: Рsat - saturation pressure, MPa.
Rpr = (1-0.15) 5 = 4.25 MPa = 4.25 106 Pa
The pump suspension depth is determined:
HDIN + Rpr / Rcm g (3.5)
electric centrifugal pump submersible well
L = 1523+4.25 106/771 9.8=1124 m
The temperature of the formation fluid at the pump intake is determined:
where Tmel - reservoir temperature, °C; GT - temperature gradient, °C/1m.
T = 50-(2250-1124) 0.02=27.5°C
The volumetric coefficient of the liquid is determined at the pressure at the pump inlet:
where B is the volumetric coefficient of oil at saturation pressure; is the volumetric water cut of the product;
Ppr - pressure at the pump inlet, MPa;
Psat - saturation pressure, MPa.
B*=0.5+(1-0.5)=1.1
The fluid flow rate at the pump inlet is calculated:
(3.8)
pr = 120·1.1=132 m3/day=0.0015 m3/s
The volumetric amount of free gas at the pump inlet is determined:
where G is the gas factor, m 3 /m 3.pr = 42 = 6.3 m 3 /m 3
The gas content at the pump inlet is determined:
βin = 1 / [(1+4.25/5) /1.1) / 6.3+1]=0.8
The gas flow at the pump inlet is calculated:
g.pr.s =132·0.8/(1-0.8)=528 m 3 /s
The reduced gas velocity in the section of the casing at the pump inlet is calculated:
(3.12)
where fskw is the cross-sectional area of the well at the pump intake.
Sq = π d2/4,
where: d - casing diameter, msv = 3.14·0.132/4=0.013 m2
C = 528/0.013=40615 m/day=0.47 m/s
The true gas content at the pump inlet is determined:
where Sp is the rate of ascent of gas bubbles, depending on the water cut of the well production (Sp = 0.02 cm/s at b<0,5 или Сп = 0,16 см/с при b>0,5).
φ = 0.8/=0.8
The work of gas in the section "bottomhole - pump intake" is determined:
Рг1 = 5[-1]=2.35 MPa
The work of gas in the section “pump injection - wellhead” is determined:
Values with the “buffer” index refer to the section of the wellhead and are “buffer” pressure, gas content, etc.
V*buf=0.5+(1-0.5)=1.05
βbuf = 1/[((1+4.25/5)/1.05)/32.8+1]=0.95
φbuf = 0.95/=0.95
Pr2 = 5[-1]=3 MPa
The required pump pressure is determined:
where Ndin is the depth of the dynamic level;
Р6уф - buffer pressure;
Рг1 - gas operating pressure in the section "bottom hole - pump intake";
Pg2 is the gas operating pressure in the section “pump discharge - wellhead”.
The size of the submersible centrifugal pump is selected based on the pump inlet flow rate, the required pressure (pump pressure) and the internal diameter of the casing. [Figure 10 Characteristics of centrifugal pumps, parameters of pumps of the ETSNA type, ETSNAK TU 3631-025-21945400-97].
The values characterizing the operation of this pump in the optimal mode (flow, pressure, efficiency, power) and in the flow mode equal to “O” (pressure, power) are determined.
New=475 m, ηow=0.60, Now=15kW
The coefficient of change in pump flow when operating on an oil-water-gas mixture relative to the water characteristic is determined:
where ν is the effective viscosity of the mixture, m 2 /s*10-5; QoB - optimal pump flow on water (Figure 10), m 3 /s.
КQν =1-4.95 0.0000410.85 0.0019-0.57=0.967
The coefficient of change in pump efficiency due to the influence of viscosity is calculated:
Кην = 1-1.95·0.0000410.4/0.00190.28=0.8
20. The gas separation coefficient at the pump inlet is calculated:
where fwell is the area of the ring formed by the inner wall of the casing and the pump casing, m2.
skv.k = fskv + fn,
where: fn - cross-sectional area of the pump, m 2.
n =π d2n/4,
where: dn - pump diameter, (Handbook on oil production Andreev V.V. Urazakov K.R., Chapter 6 Operation of oil wells with rodless pumps. Installations of submersible centrifugal pumps, table 1), m.n = 3.14 0, 1242/4=0.012 m 2 borehole =0.013-0.012=0.001 m 2
Kc = 1/=0.1
Table 1 - Installations of submersible centrifugal pumps
|
Index |
Installation group |
|||||
|
Transverse installation size, mm |
||||||
|
|
|
|||||
|
Inner diameter of operating |
||||||
|
columns, mm |
||||||
21. The relative fluid flow at the pump inlet is determined:
(3.20)
where QoB is the supply in optimal mode according to the “water” characteristics of the pump, m 3 /s. = 0.0015/0.0019 = 0.78
The relative flow at the pump inlet is determined at the corresponding point in the water characteristics of the pump:
(3.21)
pr = 0.0015/0.0019·0.967=0.82
The gas content at the pump intake is calculated taking into account gas separation:
. (3.22)
βpr =0.8·(1-0.1)=0.72
The coefficient of change in pump pressure due to the influence of viscosity is determined:
KHv = 1-(1.07 0.0000410.6 0.82/0.00190.57)=1
To determine changes in pressure and other performance indicators of centrifugal submersible pumps with a liquid viscosity significantly different from the viscosity of water and the viscosity of Devonian oil in reservoir conditions (more than 0.03-0.05 cm 2 /s), and an insignificant gas content at the first stage intake pump to take into account the influence of viscosity, you can use the P.D. nomogram. Lyapkova. We don't need this diagram for our values.
The coefficient of change in pump pressure is determined taking into account the influence of gas:
A = 1/=0.032
K = [(1-0.8)/(0.85-0.31 0.82)0.032]=0.2
The pump pressure on water at optimal mode is determined:
(3.25)
H = 8.4 106/771 9.8 0.2 1 = 5559 m
The required number of pump stages is calculated:
H/hcT (3.26)
where hc is the pressure of one stage of the selected pump.s = Htable/100,
where: Htable - pressure (Figure 10), m.st =1835/100=18.35 m=5595/18.35=304
The Z number is rounded to a higher integer value and compared to the standard number of stages of the selected pump size. If the calculated number of stages turns out to be greater than that specified in the technical documentation for the selected pump size, then you must select the next standard size with a larger number of stages and repeat the calculation starting from point 17.
If the estimated number of steps is less than specified in technical specifications, but their difference is no more than 5%, the selected pump size is left for further calculation. If the standard number of stages exceeds the calculated one by 10%, then a decision is necessary to disassemble the pump and remove the extra stages. Another option may be to consider using a choke in the wellhead equipment. Further calculations are carried out from paragraph 18 for new values of the operating characteristic.
The pump efficiency is determined taking into account the influence of viscosity, free gas and operating mode:
(3.27)
where ηоВ is the maximum efficiency of the pump for water characteristics.
η = 0.967 1 0.6 = 0.58
29. The pump power is determined:
8.4 106 0.0019/0.58=27517 W=27.5 kW
The power of the submersible motor is determined:
(3.29)
where: ηSPE - efficiency of the submersible electric motorSPE = 27.5/0.54=51 kW
Check the pump for the ability to extract heavy liquid.
In wells with possible flow or release of liquid when changing the well pump, killing is carried out by pouring heavy liquid (water, water with weighting agents). When lowering a new pump, it is necessary to pump out this “heavy liquid” from the well so that the installation begins to operate at optimal mode when extracting oil. In this case, you must first check the power consumed by the pump when the pump pumps heavy liquid. The formula for determining power includes the density corresponding to the heavy liquid being pumped (for the initial period of its selection).
At this power, possible engine overheating is checked. An increase in power and overheating determines the need to equip the installation with a more powerful engine.
Upon completion of heavy fluid withdrawal, the displacement of heavy fluid from the tubing by the formation fluid in the pump is checked. In this case, the pressure created by the pump is determined by the characteristics of the pump's operation on the formation fluid, and the backpressure at the discharge is determined by the column of heavy fluid.
It is also necessary to check the pump operation option, when heavy liquid is pumped not into the drain, but to the spout, if this is permissible according to the location of the well.
Checking the pump and submersible motor for the possibility of pumping out heavy liquid (killing liquid) during well development is carried out according to the formula:
where ρhl is the density of the killing fluid, (920 kg/m 3).
Рgl = 920·9.8·2250+1.1·106+5.5·106-11.2·106=14.7 MPa
In this case, the pump pressure during well development is calculated:
(3.31)
Ngl = 14.7 106/920 9.8 = 1630 m
Ngl>N; 1630>475
The value of Ngl is compared with the pressure N of the pump's certified water characteristics.
The pump power is determined during well development:
(3.32)
hl =14.7·106·0.0019/0.58=48155 W=48.15 kW
Power consumed by a submersible electric motor during well development:
(3.33)
PED.hl = 48.15/0.54=90 kW
The installation is checked for the maximum permissible temperature at the pump intake:
°С>27.5°С
[T] - the maximum permissible temperature of the pumped liquid at the intake of the submersible pump.
The installation is checked for heat removal by the minimum permissible coolant velocity in the annular section formed by the inner surface of the casing at the installation site of the submersible unit and the outer surface of the submersible motor, for which we calculate the flow rate of the pumped out liquid:
where is the area of the annular section; D is the internal diameter of the casing; d - outer diameter of the motor = 0.785·(0.132-0.1162)=0.0027m2 = 0.0019/0.0027=0.7 m/s
If the flow rate of the pumped liquid W is greater than the minimum permissible speed of the pumped liquid [W], the thermal regime of the submersible motor is considered normal.
If the selected pumping unit is not able to extract the required amount of kill fluid at the selected suspension depth, it (suspension depth) increases by ΔL = 10-100 m, after which the calculation is repeated, starting from point 5. The value of ΔL depends on the availability of time and capabilities computer technology calculator.
After determining the suspension depth of the pump unit using an inclinogram, the possibility of installing the pump at the selected depth is checked (by the rate of curvature gain per 10 m of penetration and by the maximum angle of deviation of the well axis from the vertical). At the same time, the possibility of lowering the selected pumping unit into a given well and the most dangerous sections of the well, the passage of which requires special care and low lowering speeds during PRS, are checked.
The data required for the selection of installations on the configuration of the installations, characteristics and main parameters of pumps, motors and other components of the installations are given both in this book and in specialized literature.
To indirectly determine the reliability of a submersible electric motor, it is recommended to evaluate its temperature, since overheating of the motor significantly reduces its operating life. An increase in winding temperature by 8-10°C above that recommended by the manufacturer reduces the service life of some types of insulation by 2 times. The following calculation procedure is recommended. Calculate power losses in the engine at 130°C:
where b2, c2 and d2 are the calculated coefficients; Nн and ηд.н - rated power and efficiency of the electric motor, respectively. Engine overheating is determined by the formula:
where b3 and c3 are design coefficients.
Due to cooling, losses in the motor are reduced, which is taken into account by the Kt coefficient.
where b5 is the coefficient.
(3.41)
The temperature of the stator windings of most motors should not exceed 130°C. If the power of the selected engine does not match that recommended in the picking list, an engine of a different size of the same size is selected. In some cases, it is possible to select a motor with a larger diameter, but in this case it is necessary to check the transverse dimension of the entire unit and compare it with the internal diameter of the well casing.
When choosing a motor, it is necessary to take into account the temperature of the surrounding fluid and its flow rate. The engines are designed to operate in environments with temperatures up to 90°C. Currently, only one type of engine allows the temperature to rise to 140°C, and a further increase in temperature will reduce the service life of the engine. This use of the engine is permissible in special cases. It is usually desirable to reduce its load to reduce overheating of the winding wires. Each engine has a recommended minimum flow rate based on its cooling conditions. This speed needs to be checked.
Checking cable and tubing parameters
When checking the previously selected cable, it is necessary to take into account mainly three factors: 1) energy loss in the cable; 2) reducing the voltage in it when starting the installation; 3) cable size.
Energy losses in the cable (in kW) are determined from the following relationship:
where I is the motor current; Lcable - the entire length of the cable (depth of engine descent and approximately 50 m of cable on the surface); Ro - active resistance of 1 m of cable length, cable = L+50.cable = 1124+ 50=1174 m
where ρ20 is the resistivity of the cable core at 20°C, taking into account cold-pressing and twisting, taken equal to 0.0195 Ohm mm 2 /m; q - cross-sectional area of the cable core, mm 2; α is the temperature coefficient of linear expansion of copper, equal to 0.0041/°C; tcab is the temperature of the cable core, which can be taken in approximate calculations to be equal to the average temperature in the wellbore.о = (·(1.31)·0.0195/50)10=0.53 Ohm/km
∆Ncab = 3·37.5·0.53·1174·10-3=70 kW
The permissible energy loss in a cable can be determined economic calculation when comparing the cost of additional energy and the cost of replacing a cable with a larger cross-section and lower energy losses. Approximately, it is possible to limit energy losses to 6-10% of the total power consumed by the installation. The decrease in voltage in the cable during operation of the installation is compensated by the transformer, therefore, its operating voltage is supplied to the electric motor in normal operation. But when starting the engine, the current increases 4-5 times and the voltage drop can be so significant that the engine will not start. Therefore, it is necessary to check the voltage drop in the cable during startup. This is especially important with long cable lengths. The voltage reduction is determined from the dependence.
where Ho is inductive resistivity cable, Ohm/m; for a cable with a cross-sectional area of 25 and 35 mm 2 is equal to 0.1 103 Ohm/m; cos φ and sin φ are the power and reactive power factors of the installation, respectively; The power factor of the installation is quite high due to the considerable length of the cable; with the correct installation configuration it is equal to 0.86-0.9.
∆Ustart = (0.53 0.86+0.1 0.6) 65 1174/100=638 V
The permissible voltage drop is indicated in the factory characteristics of the engine. It is compared with that calculated using formula (3.45).
Permissible cable cross-sections are checked taking into account the dimensions of other installation elements.
The tubing is checked for acceptable hydraulic resistance to flow, strength and diameter, ensuring the passage of equipment into the well. When fluid moves, pressure loss should not exceed 5-6% of the useful pump pressure.
Hydraulic resistances are determined from the dependence
where: λ - Darcy coefficient,
λ = 0.021/d0.3n
where: dн - pump diameter (Catalog of Installation of submersible centrifugal pumps for the oil industry = 0.124 mm), mm.
λ = 0.021/0.1240.3=0.04
λ = 0.021/0.1160.3=0.07
∆Р =771·0.04·(1174·(4.1∙10-5)2/2·0.130)=0.00024 Pa
When a gas-liquid mixture moves, this determination of resistance gives very approximate results.
The strength of the pipes is checked taking into account the weight of the tubing string, the pressure of the pumped liquid and the weight of all equipment (cable, submersible unit).
Dimensions are checked in accordance with the instructions in the next section of this paragraph.
3 Checking the diametrical dimensions of submersible equipment
The diametrical dimension of the submersible equipment must ensure its descent and ascent into the well without damage and sufficient full use of the internal cavity of the well.
Typically, the gap between the equipment and the casing pipes is 3-10 mm. If the well depth is significant and its curvature is increased, it is necessary to take an increased gap. The diametrical dimension is usually determined in three sections along the length of the equipment.
The first section is taken from the tubing coupling. Here is the diametrical dimension equal to the sum diameters of the cable and coupling, taking into account plus tolerances for their manufacture. The second section is taken above the submersible unit, taking into account its size and the size of the nearest tubing coupling, which has a round cable.
Such a coupling is usually located 10-20 m from the unit and, together with the latter, represents a rather rigid system. If the size of this section exceeds the permissible limit, then the pipes are replaced with a smaller size at a length of 40-50 m. Thus, the rigidity of this system (tubing - submersible unit) is reduced without a significant increase in pressure losses in the pipes.
The last section is the diametrical cross-section of the unit itself (Da) without coupling, pipes and round cable.
If the dimensions of the equipment are unacceptable in the first and last sections, it is necessary to change the size of the cable, tubing, pump or motor. At the same time, the calculations also check the corresponding stages of selecting installation units specified in the previous sections.
4 Checking the parameters of the transformer and control station
The transformer is tested to ensure that it can raise the voltage to the sum of the voltage required by the motor and reduce the voltage in the cable during motor operating mode. In addition, the power of the transformer is checked.
The voltage reduction in the cable is determined by the dependence, but taking into account the operating, and not the starting current strength. Power is checked by comparing the power of the transformer (in kWA) and the power that needs to be introduced into the well (in kVA).
When choosing a control station, it is necessary to take into account the type of transformer, the current supplied to the motor, and some other conditions.
The efficiency of surface equipment for calculations can be taken to be approximately 0.98.
Chapter 3. Safety precautions
1 Occupational safety during operation of borehole centrifugal pump installations
When installing and operating ESP installations, safety rules in the oil industry, design rules, technical operation rules and safety rules for the operation of electrical installations by consumers must be strictly observed. In addition, almost all oil companies have developed either Enterprise Standards or Regulations for carrying out basic work with ESP installations.
All work with the electrical equipment of the installation is carried out by two workers, and one of them must have an electrician qualification of at least group 3.
Turning the unit on and off by pressing a button or turning a switch located on the outside of the control station door is carried out by personnel with qualifications of at least group 1 and who have undergone special training.
The ESP installation equipment is installed in accordance with the operating manual.
The cable from the control station to the wellhead is laid on metal stands at a height of 0.5 m from the ground. This cable must have an open connection along its length so that gas from the well cannot pass through the cable (for example, through twisted wires in the core) indoors control stations. To do this, a metal box is made in which the connection of the cable cores is placed, preventing the movement of gas to the control station.
All ground equipment of the installation is reliably grounded.
The resistance of the ground loop should be no more than 4 ohms.
During hoisting and hoisting operations, the speed of movement of pipes and cables should not be more than 0.25 m/s. For winding and unwinding the cable from the drum, UPK installations with remote control mechanized drum drive.
When loading and unloading equipment of ESP installations from vehicles, it is necessary to comply with safety rules when rigging work. In particular, you must not be in the path of a cable drum being lowered by a winch from the slopes of a machine or sled. You can't be behind him either. All loading and unloading devices must be periodically tested and inspected and adjusted at least once every 3 months.
All parts of the ESP unit must be securely fastened to the transport unit. The pumps, hydraulic protection and electric motor are secured with brackets and screws, the transformer and control station are secured with chains, and the drum is secured to its axis with four screw braces.
Conclusion
During oil production in fields, during the operation of wells, information used in control over development is continuously collected, it is processed, analyzed and used to develop geological and technical measures.
ESP selection usually refers to the selection of such standard sizes of a pump, a submersible electric motor with a protector, an electric cable, an autotransformer or transformer, a tubing diameter and a pump lowering depth into the well, the combination of which in a steady state ensures a given fluid extraction at the lowest cost.
The main direction of geological and technical measures is to increase the productivity of production wells and optimize their regimes. In this case, it is necessary to make the optimal selection of the main underground equipment. Optimal selection means such a match between the characteristics of the well and underground equipment, in which the energy costs for lifting the well fluid to the wellhead are minimized.
To select high-quality equipment and determine the operating mode of a well, it is necessary:
clean the face at each TRS;
use proven results of well hydrodynamic studies;
apply modern installations and technologies for the extraction of hydrocarbon reserves:
carefully study data on geophysical surveys of wells in order to accurately determine the occurrence of productive formations.
List of sources used
1. Ivanovsky V.N., Darishchev V.I., Sabirov A.A., Kashtanov V.S., Beijing S.S. Downhole pumping units for oil production. - M: State Unitary Enterprise Publishing House "Oil and Gas" Russian State University of Oil and Gas named after. THEM. Gubkina, 2002. - 824 p.
Mishchenko I.T. Downhole oil production: Tutorial for universities. - M: Federal State Unitary Enterprise Publishing House "Oil and Gas" Russian State University of Oil and Gas named after. THEM. Gubkina, 2003. - 816 p.
Ivanovsky V.N., Darishchev V.I., Kashtanov V.S. etc. Equipment for oil and gas production. Part 1. M.: Oil and Gas, 2002. - 768 p.
Andreev V.V., Urazakov K.R., Dalimov V.U. Handbook of oil production. M.: Nedra - Business Center LLC, 2000. - 374 p.
5. Handbook of oil production / V.V. Andreev, K.R. Urazakov, U. Dalimov and others; Ed. K.R. Urazakova. 2000. - 374 pp.: Il.
Oilfield equipment: Handbook / Ed. I. Bukhalenko. 2nd ed., revised. and additional - M., Nedra, 1990.
ESP calculation.doc
3.Technical part3.1. Equipment for operating oil wells using submersible rodless pumps.
Installations of submersible centrifugal pumps in modular design UETsNM and UETsNMK are designed for pumping from oil wells, including inclined formation fluid containing oil, water and gas, and mechanical impurities. The units have two versions: conventional and corrosion-resistant. An example of an installation designation when ordering: UETsNM5 - 125 - 1200 VKO2 TU - 26 - 06 - 1486 - 87, when corresponding and in technical documentation it is indicated: UETsNM5 - 125 - 1200 TU26 - 06 - 1486 - 87, where: U - installation, E - drive from a submersible motor, N - pump, M - modular, 5 - pump group, 125 - flow m3/day, 1200 - pressure, VK - configuration option, 02 - serial number of the configuration option according to the specifications.
For installations (UETSNM and U) of corrosion-resistant design, the letter “K” is added before the designation of the pump group.
The UETsNM and UETsNMK installations consist of a submersible unit, a cable, and an assembly of ground-based electrical equipment - a transformer complex substation (individual KTPPN or cluster KTPPNKS).
A pumping unit consisting of a submersible centrifugal pump and a motor (Electric heater with hydraulic protection) is lowered into the well on a tubing string.
The pumping unit pumps out formation fluid from the well and delivers it to the surface through the tubing string.
The cable that supplies electricity to the electric motor is attached to the hydraulic protection. The pump and tubing with metal belts.
An integrated transformation substation converts the voltage at the electric motor terminals, taking into account voltage losses in the cable, and provides control of the operation of the pumping unit, installation and its protection in abnormal conditions.
Submersible pump, centrifugal, modular. The check valve is designed to prevent reverse rotation of the pump rotor under the influence of the liquid column in the tubing during stops and thereby facilitate the restart of the pump unit. The check valve is screwed into the pump head module, and the drain valve is screwed into the check valve body. The drain valve is used to drain fluid from the tubing cavity when lifting the pumping unit from the well.
To clean formation fluid containing more than 25-35% (by volume) of free gas at the receiving grid of the input module, a gas separator pump module is connected to the pump.
The motor is asynchronous, submersible, three-phase, squirrel-cage, two-pole, oil-filled.
At the same time, the installations must be equipped with a complete device ShGS 5805-49TZU.
The cable assembly is connected to the electric motor using a cable entry coupling. The wellhead equipment ensures suspension of the tubing string with the pumping unit and cable assembly on the casing flange, sealing of the annulus, and drainage of formation fluid into the flowline. Submersible centrifugal modular pump, multistage, vertical design. The pump is produced in two versions: the conventional ETsNMK and the corrosion-resistant ETsNMK. The pump consists of an inlet module, a section module, a head module, a check valve and a drain valve.
It is allowed to reduce the number of module sections in the pump if the submersible unit is equipped accordingly. Engine of required power. To pump out formation fluid containing more than 25% (by volume) of free gas at the wall of the pump inlet module, a gas separator pump module should be connected to the pump. The gas separator is installed between the input module and the section module. The connection between the modules, the section module and the input module with the motor is flanged. The connections are sealed with rubber rings. The connection of the shafts of the module sections with each other, the module section with the input module shaft with the engine hydraulic protection shaft is carried out by splined couplings.
The shafts of the gas seporator, section module and input module are connected to each other also through splined couplings.
The impellers and guide vanes of standard pumps are made of modified gray cast iron; for corrosion-resistant ones, they are made of modified 4N16D72ХШ.
The impellers of conventional pumps can be made from radio-modified polyamide. The head module consists of a housing, on one side of which there is an internal conical thread for connecting a check valve (pump-compressor tube), on the other side there is a flange for connecting sections of two ribs and a rubber ring to the module. The fins are attached to the body of the head module with a bolt and spring washer. A rubber ring seals the connection between the head module and the section module.
The module section consists of a housing, a shaft, a package of impeller feet and guide vanes, an upper bearing, an upper axial support, a head, a base, two ribs and rubber rings.
The number of feet in module sections is indicated in the table.
The ribs are designed to protect the flat cable with a coupling from mechanical damage against the casing wall during lowering and lifting of the pumping unit. The ribs are attached to the base of the module section with a bolt with a nut and a spring washer.
SPRING ELECTRIC MOTORS (SEM)
Submersible motors consist of an electric motor and hydraulic protection. Three-phase, asynchronous, squirrel-cage, two-pole, submersible motors, of the unified Pad series in normal and corrosion-resistant versions, climatic version B, category 45, operate from an alternating current network with a frequency of 50 Hz and are used as a drive for submersible centrifugal pumps in a modular design for pumping formation fluid from oil wells. The engines are designed to operate in formation fluid (a mixture of oil and water in any proportions at a temperature of 110C).
HYDROPROTECTION OF SUBMERSIBLE ELECTRIC MOTORS.
Hydraulic protection is designed to prevent formation fluid from entering the internal cavity of the electric motor, compensating for changes in the volume of oil in the internal cavity from the temperature of the electric motor and transmitting torque from the electric motor shaft and to the pump shaft. 2 variants of hydraulic protection designs have been developed for engines of the unified series; open type - P
92, PK92, P114, PK114, and closed type - P92D, PK92D, (with diaphragm) P11D, PK114D;
COMPLETE DEVICES SHGS5805 SERIES.
The devices are designed to control and protect submersible electric pumps for oil production with a PED series motor (including a built-in thermomanometric system) in accordance with GOST 18058 - 80 with a power of 14-100 kW and voltage up to 2300 V AC.
CABLE
To supply electric energy to the installation motor, a cable line is used, consisting of the main cable and an extension cord spliced with it with a cable entry coupling, which ensures a hermetically sealed connection of the cable line to the electric motor.
Depending on the purpose, the cable line may include round cables of the KPBK brand as the main cable; KTEBK; KTfSBK; or flat KPBP brands; KTEB; KFSB;
Flat cables of the KBPBP and KFSB brands are used as extension cords.
Round type cable entry coupling: Cables of the KPBK and KBPP brands with polyethylene insulation are intended for operation at ambient temperatures up to + 90C.
Performance characteristics of conventional ESPs
Table No. 18
| Installation size | Supply: m3/day | Head: m |
| ESP5 - 40-1400 | 25-70 | 1425-1015 |
| ESP5-40-1750 | 25-70 | 1850-1340 |
| ESP5-80-1200 | 60-115 | 1285-715 |
| ESP5-80-1800 | 60-115 | 1905-1030 |
| ESP5-130-1200 | 100-155 | 1330-870 |
| ESP5-130-1700 | 100-155 | 1940-1300 |
| ESP5-200-800 | 145-250 | 960-545 |
| ESP5-200-1350 | 145-250 | 1480-850 |
| UETSN5A-160-1400 | 125-505 | 1560-1040 |
| UETSN5A-160-1750 | 125-505 | 1915-1290 |
| UETSN5A-250-1000 | 190-330 | 1160-610 |
| UETSN5A-250-1750 | 195-330 | 1880-1200 |
| UETSN5A-360-850 | 290-430 | 950-680 |
| UETSN5A-360-1400 | 290-430 | 1610-115 |
| UETSN5A-500-800 | 420-580 | 850-700 |
| UETSN5A-500-1000 | 420-580 | 1160-895 |
| ESP6-250-1050 | 200-330 | 1100-820 |
| ESP6-250-1400 | 200-300 | 1590-1040 |
| ESP6-350-1100 | 280-440 | 1280-700 |
| ESP6-500-750 | 350-680 | 915-455 |
| ESP6-500-1000 | 350-680 | 1350-600 |
| ESP6-700-800 | 550-900 | 870-550 |
Operating characteristics of modular ESPs
Table No. 19
| Installation size | Supply: m3/day | Head: m |
| UETsNM-50-1550 | 25-70 | 1610-1155 |
| UETsNM-80-1050 | 60-115 | 1290-675 |
| UETsNM-80-1550 | 60-115 | 1640-855 |
| UETsNM-80-2000 | 60-115 | 2035-1060 |
| UETsNM5-125-1200 | 105-165 | 1305-525 |
| UETsNM5-125-1500 | 105-165 | 1650-660 |
| UETsNM5 - 200-800 | 150-265 | 970-455 |
| UETsNM5-200-1100 | 150-265 | 1320-625 |
| UETsNM5A-160-1050 | 125-205 | 1210-715 |
| UETsNM5A-250-1300 | 125-340 | 1475-775 |
| UETsNM5A-250-1400 | 125-340 | 1575-825 |
| UETsNM5A-400-950 | 300-440 | 1180-826 |
| UETsNM5A-400-1200 | 300-440 | 1450-1015 |
| UETsNM5A-500-800 | 430-570 | 845-765 |
| UETsNM5A-500-1000 | 430-570 | 1035-935 |
| UETsNM6-250-1250 | 200-340 | 1335-810 |
| UETsNM6-320-1400 | 280-440 | 1505-775 |
| UETsNM6-500-1050 | 380-650 | 1215-560 |
| UETsNM6-500-1400 | 380-650 | 1625-800 |
3.2 Performance characteristics of electric submersible pump (ESP).
All types of pumps have a passport operating characteristic in the form of dependence curves H(Q) (pressure, flow); n(Q)
(efficiency feed); N (Q) (power consumption, supply).
Typically, these dependencies are given in the range of operating flow rates or a slightly larger range.
Any centrifugal pump, including an ESP, can operate with a closed discharge valve (i.e. A: Q = 0). Н=Н max out without backpressure on the discharge (t.ВQ=Q max: Н=0).
Since the useful work of the pump is proportional to the product of the supply and the pressure, then for these 2 extreme modes the useful work will be equal to 0, and therefore the efficiency. = 0.
At a certain ratio of Q and H, minimal internal losses, efficiency. reaches a maximum value of approximately 0.5-0.6.
Typically, pumps with low flow and small diameter impellers, as well as with a large number of feet, have reduced efficiency. The supply and pressure corresponding to the maximum efficiency is called the optimal operating mode of the pump. The n(Q) dependence around its maximum decreases smoothly, so the ESP can operate under conditions that deviate in one direction or another from the optimal one. The limits of these deviations depend on the specific characteristics of the ESP and must correspond to the reduction in efficiency. by 3-5%. This gives rise to a whole range of possible modes, which is called the recommended range.
Selection of a pump for a well comes down to choosing a standard size for the ESP so that it operates under optimal conditions or conditions recommended for pumping a given flow rate from a given depth. Currently produced pumps are designed for nominal flow rates from 40 (ETSN 5-40-950) to 500 m3/day (ETSN 6-50-750) and pressure from 450 m (ETSN6-500-450) to 1500 m (ETSN6-100-1500 ). In addition, there are pumps for special purposes, for example, for pumping water into formations. These pumps have a flow rate of up to 3000 m3/day and a head of up to 1200 m. The pressure that the pump can overcome is directly proportional to the number of feet and depends on the size of the impeller, i.e. on the radial dimensions of the pump.
With an outer diameter of the pump casing of 92 mm, the average pressure developed by one stage when operating on water is 3.86 m, with fluctuations from 3.69 to 4.2 m.
With an outer diameter of 114 mm, the average head is 5.76 m with fluctuations from 5.03 m to 6.84 m.
3.3 Technical conditions for the operation of ESP in modular design
Maximum density of water-oil mixture - 1400kg/m3
Kinematic viscosity - 1mm2/sec
Hydrogen indicator pH - 6.0 - 8.5
Maximum mass amount (concentration) of solid particles - 0.01% (0.1 g/l)
The water cut of pumping liquid is no more than 99%.
The maximum content of free gas at the intake of a pump with a gas separator is 25% - 50%.
Hydrogen sulfide content H2S - 0.01 g/l.
The temperature of the pumped liquid is no more than 90C.
For the anti-corrosion version of the UECNM, the hydrogen sulfide content H2S is 125 g/l.
The guaranteed operating time of the ESP before repair is 830 days. The period until write-off is 5.5 years.
Table No. 20
| Installation | Pump | Pump module gas separator | Engine |
| UETsNM5-50-1300 | ETsNM5-50-1300 | 1MNG - 5 | PED432-103V5 |
| UETsNM5-50-1300 | ETsNM5-50-1300 | 1MNG - 5 | PED4K32-103V5 |
| UETsNM5-50-1550 | ETsNM5-50-1550 | 1MNG - 5 | PED432-103V5 |
| UETsNM5-50-1550 | ETsNM5-50-1550 | 1MNG - 5 | PED4K32-103V5 |
| UETsNM5-50-1700 | ETsNM5-50-1700 | 1MNG - 5 | PED432-103V5 |
| UETsNM5-50-1700 | ETsNM5-50-1700 | 1MNG - 5 | PED4K32-103V5 |
| UETsNM5-80-1200 | ETsNM5-80-1200 | 1MNG - 5 | PED4K32-103V5 |
| UETsNM5-80-1550 | ETsNM5-80-1550 | 1MNG - 5 | PED432-103V5 |
| UETsNM5-80-1550 | ETsNM5-80-1550 | 1MNG - 5 | PED4K32103V5 |
| UETsNM5-80-1800 | ETsNM5-80-1800 | 1MNG - 5 | PED445-103V5 |
| UETsNM5-80-1800 | ETsNM5-80-1800 | 1MNG - 5 | PED4K45-103V5 |
| UETsNM5-125-1200 | ETsNM5125-1200 | 1MNG - 5 | PED445-103V5 |
| UETsNM5-125-1200 | ETsNM5-125-1200 | 1MNG - 5 | PED4K45-103V5 |
| UETsNM5-125-1300 | ETsNM5-125-1300 | 1MNG - 5 | PED445-103V5 |
| UETsNM5-125-1300 | ETsNM5-125-1300 | 1MNG - 5 | PED4K45-103V5 |
| UETsNM5-125-1800 | ETsNM5-125-1800 | 1MNG - 5 | PED4S63-103V5 |
| UETsNM5-125-1800 | ETsNM5-125-1800 | 1MNG - 5 | PED4SK63-103V5 |
| UETsNM5-200-1400 | ETsNM5-200-1400 | 1MNG - 5 | PED4S90-103V5 |
| UETsNM5-200-800 | ETsNM5-200-800 | 1MNG - 5 | PED445-103V5 |
| UETsNM5A-160-1450 | ETsNMK5A-160-1450 | 1MNG - 5A | PED4S63-103V5 |
| UETsNM5A-160-1450 | ETsNMK5A-160-1450 | 1MNG - 5A | PED4SK63-103V5 |
| UETsNM5A-160-1750 | ETsNMK5A-160-1750 | 1MNG - 5A | PED4S90-117V5 |
| UETsNM5A-160-1750 | ETsNMK5A-160-1750 | 1MNG - 5A | PED4SK90-117V5 |
| UETsNM5A-160-1750 | ETsNMK5A-160-1750 | 1MNG - 5A | PED463-117V5 |
| UETsNM5A-250-1000 | ETsNMK5A-250-1000 | 1MNG - 5A | PED4K63-117V5 |
| UETsNM5A-250-1000 | ETsNMK5A-250-1000 | 1MNG - 5A | PEDUS90-117V5 |
| UETsNM5A-250-1400 | ETsNMK5A-250-1400 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-250-1400 | ETsNMK5A-250-1400 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-250-1700 | ETsNMK5A-250-1700 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-250-1700 | ETsNMK5A-250-1700 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-250-1800 | ETsNMK5A-250-1800 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-250-1800 | ETsNMK5A-250-1800 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-400-950 | ETsNMK5A-400-950 | 1MNG - 5A | PEDUSK90-117V5 |
| UETsNM5A-400-950 | ETsNMK5A-400-950 | 1MNGK - 5A | PEDUSK90-117V5 |
| UETsNM5A400-1250 | ETsNMK5A-400-1250 | 1MNG - 5A | PEDUS125-117V5 |
| UETsNM5A-400-1250 | ETsNMK5A-400-1250 | 1MNG - 5A | PEDUS125-117V5 |
| UETsNM5A-500-800 | ETsNMK5A-500-800 | 1MNG - 5A | PEDUS125-117V5 |
| UETsNM5A-500-800 | ETsNMK5A-500-800 | 1MNGK - 5A | PEDUSK125-117V5 |
| UETsNM5A -500-1000 | ETsNM5A - 500-1000 | MNG-5A | PEDUSK125-117V5 |
| UETsNMK5A -500-1000 | ETsNMK5A - 500-1000 | MNGK-5A | PEDUSK125-117V5 |
| UETsNM6-250-1050 | ETsNM6-250-1050 | MNG -6 | PEDU90 -123V5 |
| UETsNMK6-250-1050 | ETsNM6-250-1050 | MNGK-6 | PEDUK90-123V5 |
| UETsNM6-250-1400 | ETsNM6-250-1400 | 1MNG - 6 | PEDUK90-123V5 |
| UETsNMK6-250-1400 | ETsNM6-250-1400 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNM6-250-1600 | ETsNM6-250-1600 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNMK6-250-1600 | ETsNM6-250-1600 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNM6-320-1100 | ETsNM6-320-1100 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNMK6-320-1100 | ETsNM6-320-1100 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNM6-500-750 | ETsNM6-500-750 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNMK6-500-750 | ETsNM6-500-750 | 1MNGK - 6 | PEDUK90-123V5 |
| UETsNM6-500-1050 | ETsNM6-500-1050 | 1MNGK - 6 | PEDUS125-117V5 |
| UETsNMK6-500-1050 | ETsNM6-500-1050 | 1MNGK - 6 | PEDUSK125-117V5 |
| UETsNM6-800-1000 | ETsNM6-800-1000 | 1MNGK - 6 | PEDUS180*-130V5 |
| UETsNMK6-800-1000 | ETsNM6-800-1000 | 1MNGK - 6 | PEDUSK180-130V5 |
| UETsNM6-1000-900 | ETsNM6-1000-900 | 1MNGK - 6 | PEDUS250-130V5 |
| UETsNMK6-1000-900 | ETsNM6-1000-900 | 1MNGK - 6 | PEDUSK250-130V5 |
| UETsNM6-1000-1000 | ETsNM6-1000-1000 | 1MNGK - 6 | PEDUSK250-130V5 |
| UETsNMK6-1000-1000 | ETsNM6-1000-1000 | 1MNGK - 6 | PEDUSK250-130V5 |
| UETsNM6-1250-800 | ETsNM6-1250-800 | 1MNGK - 6 | PEDUSK250-130V5 |
| UETsNMK61250-800 | ETsNM6-1250-800 | 1MNGK - 6 | PEDUSK250-130V5 |
| UETsNM61250-900 | ETsNM6-1250-900 | 1MNGK - 6 | PEDUS360-130V5 |
| UETsNMK6-1250-900 | ETsNM6-1250-900 | 1MNGK - 6 | PEDUSK360-130V5 |
3.6 Methodology for selecting an ESP for a well
This methodology is intended for operational calculations of technological parameters of wells equipped with ESP; the accuracy of intermediate and final calculated values are within acceptable values for field conditions.
The method uses mathematical dependencies for the parameters of water-oil-gas mixtures obtained by domestic and foreign research. The ultimate goal in this technique is to determine the point of intersection of the operating characteristics of the selected pump with the conditional characteristics of the well, i.e. finding the conditions for joint operation of the well and the pump.
The method takes into account the influence of the viscosity of the oil-water mixture on the passport (on water) characteristics. The technique is presented in the form of an algorithm, i.e. it provides a sequence of calculation operations to obtain the main technological parameters of the pump well.
Coefficient taking into account wellbore elongation
Ld - wellbore extension in m.
Hc is the vertical depth of the well, the length of the trunk for a non-deviated well, m.
Oil density in the annulus
This formula based on the results of field research is mainly for the condition Ppr Psat. Can be used for Rpr condition< Рнас в пределах не более 10% по объему. При = 0. Rpr = Rsat.
Ppr - pump intake pressure, MPa
Psas - saturation pressure, MPa
prgas content at pump intake % volume.
3.Density of the oil-water mixture kg/m3
cm = n. pl. (1-n/100) +в x n/100
n.pl. - density of reservoir oil, kg/m
в - density of produced water, kg/m3
N - water cut of produced oil, %
A coefficient that takes into account the increase in the volume of the water-oil mixture supplied to the pump intake.
Where Vpl is the volumetric coefficient of reservoir oil (Vpl > 1)
5. Viscosity of the water-oil mixture supplied to the pump intake (at n = 60%)
,
Where is Mn. pl – viscosity of reservoir oil, MPa x s
If MSM< 5 МПа х с или n >60%, then correction factors Kd = 1; Kn = 0.99;
6. Correction factor for pump flow (flow reduction factor)
Kd = 1 - 0.0162( 
cm - 5) 0.544
Correction factor for pressure (pressure reduction factor).
Reduced static level in a well operating in the mode (ESP or SRP) before transferring it to the optimal mode: m
Npn - pump suspension depth: m
ND - dynamic level: m
Rpl - reservoir pressure: MPa
Rzatr - casing pressure: MPa
P buffer - pressure on the buffer: MPa
Note: For wells converted to ESP from the flowing method, after cap. repair and immediately after drilling in formula 8, Np is accepted. n = Ns.; Nd = 0
Coefficient that brings the conditional characteristics of the well closer to the working area of the pump in terms of pressure m 6 / day 2
, Where S1, S3 - numerical values of the coefficients that determine the equation of the working part, characteristics, and pre-selected pump size.
S1 – [m], S3 – [day sq/m3]
The inverse value of the well productivity coefficient (Kpr), characterizing the mass flow rate of the water-oil mixture entering the pump intake; day/m2 MPa.
Coefficient that brings the conditional characteristics of wells closer to the working area of the pump at a supply of m3/day
) x Kd/ 2.2 x Kcm x S3; S 2 - numerical coefficient of the working part of the characteristic of a pre-selected pump size (day/m2)
Design optimal fluid withdrawal from a well under surface conditions m3/day ql = B + A + B 2 ;
Substituting equation (b) and the expression for g f from (a) and making some transformations, we obtain an expression for g f (item 12)
Design bottomhole pressure in the well MPa
Rzab = Rpl – ql/ Kpr;
Dynamic level when developing a well using liquid during well killing; m
,Where rzh.hl is the density of the killing fluid, kg/m3
Pump suspension depth: m
,
Psat - saturation pressure, MPa
Design working dynamic level in the well under steady state operating conditions; m
INITIAL DATA REQUIRED FOR CALCULATION.
10. Rpl - reservoir pressure, MPa
11. Pzatr - casing pressure, MPa
12. Rbuf - buffer pressure, MPa
Kpr - productivity coefficient m3/day MPa
Calculation of ESP selection for well 1739
Initial data for calculation:
Well flow rate Qf = 130 m 3 /day
Water cut n = 87%.
Well depth Hc = 2808m.
Pump suspension depth N.p. = 1710m.
Dynamic level N d = 610 m.
Pressure in the annulus P exp = 0.8 MPa.
Density of produced water in = 1170 kg/m3
Reservoir pressure Рpl = 25.6 MPa
Lstroke = 27.2 m.
Killing fluid density zgl = 1170 kg/m 3
Productivity coefficient Kpr = 1.62 m 3 /day MPa
Designed optimal extraction 130m 3 /day 
K d =1; Kn =0.99.
7. Preliminarily select the pump ESP5-125-1400
S1=642.37; S2=17.43; S3=0.096
A= 
9.
10.
11.
12.
13.
We accept N mon = 1650m
15. Q cm = Q ass * K cm = 120.1 * 1.014 = 121.8 m 3 /day
For the ESP pump 5-125-1400, the working area for liquid selection is 90-160 m 3 /day. Thus, the designed extraction of 136.9 m 3 /day is acceptable and the pump will operate under optimal conditions.
^
Calculation of ESP selection for well 235
Initial data for calculation:
The well is operated by an ESP unit 5-80-1550
Designed extraction 111.4 m3/day
Well flow rate Qf = 90 m 3 /day
Water cut n = 91%.
Well depth Hc = 2803m.
Pump suspension depth N.p. = 1560m.
Dynamic level N d = 780 m.
The internal diameter of the production casing D eq = 0.130 m.
Pressure in the annulus P exp = 0.9 MPa.
Density of oil in surface conditions n.pov = 840 kg/m 3
Oil density in reservoir conditions n.pl = 830 kg/m 3
Volume coefficient = 1.108
Density of produced water in = 1160 kg/m3
Saturation pressure P us = 6.23 MPa.
Reservoir pressure Рpl = 24.5 MPa
L barrel stroke = 5.6 m.
Killing fluid density zgl = 1200 kg/m 3
Productivity coefficient Kpr = 1.12 m 3 /day MPa
Oil viscosity in reservoir conditions n = 1.83 MPa*s
K d =1; Kn =0.99.
7. Preliminarily select the pump ESP5-130-1400
S1=653.92; S2=18.72; S3=0.1
A= 
9.
10.
11.
12.
13.
We accept N mon = 1300m
15. Q cm = Q ass * K cm = 94.9 * 1.0097 = 95.8 m 3 /day
Equivalent amount of water
For the ESP pump 5-130-1400, the working area for liquid selection is
90-180 m. 3 / day. Thus, the projected extraction is 111.4 m 3 /day
Calculation of ESP selection for well 3351
The well is operated by ESP pumps 5-125-1300
Initial data for calculation:
Well flow Ql = 97 m3/day
Water cut n = 50%.
Well depth Нс = 2798 m.
Pump suspension depth Np.n. = 1460m.
Dynamic level Нд = 1260 m.
The diameter of the production string is Dec = 0.130 m.
The pressure in the annulus Pzatr = 3 MPa.
Oil density in surface conditions pH.pov = 840 kg/m3
Oil density in reservoir conditions pn.pl = 830 kg/m3
Volume coefficient vn = 1.108
Density of produced water р в = 1170kg/m3
Saturation pressure Рsа = 6.23 MPa.
Reservoir pressure Rpl = 25.4 MPa
Barrel length = 12.1 m.
Density of the killing fluid p zgl = 1170 kg/m3
Productivity coefficient Kpr = 1.3 m3/day MPa
Oil viscosity in reservoir conditions Mn = 1.83 MPa x s
CALCULATION
Designed extraction 120m3/day 
9. Preliminarily select the pump ESP5-125-1400
S1=642.37; S2=17.43; S3=0.096
10.
11.
12.
13 
14.
15.
We accept Npn = 1850m
16
17. Q cm = Qzopt x Kcm = 127 x 1.054 = 134 cubic meters/day
Equivalent amount of water
Calculation of ESP selection for wells 1713
Well flow rate Q and = 80 m 3 /day
Water cut H = 67%
Well depth H With = 2845 m.
Pump suspension depth H p.n. = 1750 m.
Dynamic level H d = 1080 m.
Production string diameter D ek = 0,130 m.
Annular pressure P cost= 1.3 MPa
Density of oil at surface conditions P n pov = 840 kg/m 3
Oil density in reservoir conditions P n pl = 830 kg/m 3
Volume coefficient IN n 1,108.
Density of produced water P V =1170 kg/cm 3
Saturation pressure P us=6.23 MPa
Reservoir pressure P pl=27.3 MPa
L beat trunk = 0.7 m.
Killing fluid density P f ch = 1170 kg/m 3
Productivity factor K etc = 0,27 m 3 /day MPa
Viscosity in oil under reservoir conditions M n= 1.83 MPa. With
Calculation:
Projected selection 130 m
3
/day
8.
S 1 =642,37; S 2 =17,43; S 3 =0,096
10.
11.
12.
13 
14.
15.
We accept N Mon = 1500m
Equivalent amount of water
For the ESP pump 5-125-1400, the working area for liquid selection is 90-160 m.cub/day. Thus, the projected selection is 146.2 m.cub/day let's assume the pump will operate in optimal mode.
Calculation of ESP selection for wells 3351
Calculation:
Projected selection 120 m 3
/day
Pre-select pump ESP5-125-1400
S 1
=642,37; S 2
=17,43; S 3
=0,096
We accept N Mon = 1850m
Equivalent amount of water
For the ESP pump 5-125-1400, the working area for liquid selection is 90-160 m3/day. Thus, the designed extraction of 138.7 cubic meters per day is acceptable and the pump will operate in optimal mode.
Calculation of ESP selection for wells 1693
Calculation:
Projected selection 120 m 3
/day
9. To select liquid, we first use the pump ESP5-125-1400
S 1
=653,92; S 2
=18,72; S 3
=0,1
We accept N Mon = 1000m
Equivalent amount of water
For the ESP pump 5-130-1400, the working area for liquid selection is 90-180 m.cub/day. Thus, the projected selection is 135.6 m.cub/day let's assume the pump will operate in optimal mode.
Technological operating mode of oil wells of the T2 formation of the Kurmanaevskoye field.
| Nwell.Opt | M/r Plast | Fund | Way | Q(liquid)m3 | Qoil t/day | Qwater t/day |
| 246d | Kur T2 | ext | ESP50 | 50 | 3,4 | 53,4 |
| 102d | Doc T2 | ext | ESP50 | 60 | 32 | 14,6 |
| 106d | DocT2 | ext | ESP50 | 50 | 27,6 | 14,4 |
| 235d | KurT2 | ext | ESP80 | 90 | 6,8 | 95 |
| 248d | KurT2 | ext | ESP50 | 50 | 10,5 | 43,9 |
| 1607d | DocT2 | ext | ESP50 | 50 | 27,6 | 20,5 |
| 1608d | DocT2 | ext | ESP50 | 50 | 3,4 | 53,6 |
| 1614d | DocT2 | ext | ESP50 | 50 | 32 | 13,5 |
| 1615d | DocTT2 | ext | ESP50 | 50 | 38,3 | 7 |
| 1616d | DocT2 | ext | ESP50 | 40 | 3,4 | 50,6 |
| 1622d | DocT2 | ext | ESP20 | 15 | 3,2 | 15,2 |
| 1693d | KurT2 | ext | ESP80 | 80 | 11,1 | 79,4 |
| 1713d | KurT2 | ext | ESP80 | 80 | 22,1 | 62,7 |
| 1716d | KurT2 | ext | ESP50 | 55 | 12,9 | 46,1 |
| 1733d | KurT2 | ext | ESP20 | 25 | 2,5 | 25,7 |
| 1739d | KurT2 | ext | ESP125 | 130 | 14,2 | 128,9 |
| 1741d | KurT2 | ext | ESP50 | 55 | 9,7 | 51 |
| 3310d | KurT2 | ext | ESP80 | 80 | 1,3 | 91,8 |
| 3351d | KurT2 | ext | ESP80 | 55 | 17,6 | 39,8 |
| 19 | 1118 | 276 |
^ Conclusions on the technical part.
Reservoir T 2 is in the final stages of development.
Injecting water into the reservoir allows you to maintain reservoir pressure to ensure design fluid withdrawals.
The physical and chemical properties of the T-2 formation meet the technical requirements for ESP operation.
Existing standard sizes of ESPs allow for various selections in the T-2 formation.
The technological operating mode of the wells is compiled taking into account the design fluid withdrawals and optimal operation of the ESP equipment.
ESPs in the wells of the T-2 formation are operated in optimal modes, however, a number of wells can be switched to increased fluid extraction (wells Nos. 1693, 1713, 3310, 3351), while maintaining optimal operation of the submersible equipment.
The operating time of the ESP for the T-2 formation is significantly higher than the average for the NGDU Buzulukneft - over 400 days with an average of 350 days
Carrying out geological and technical measures at the wells of the T-2 formation in conjunction with the injection of water for reservoir pressure maintenance makes it possible to slow down the rate of natural decline in oil production.
Optimal design fluid withdrawals from wells make it possible to increase the oil recovery factor of the T-2 formation
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1. Characteristics of equipment during operation of ESP wells
well drilling electric centrifugal pump
Electric centrifugal pump installations are designed for pumping out of oil wells, including inclined formation fluids containing oil, water and gas, and mechanical impurities. Depending on the number of different components contained in the pumped-out liquid, the pumps of the installations have a standard design and a version with increased corrosion and wear resistance.
Installations of electric centrifugal pumps (ESP), as a rule, are used in high-yield wells, providing the highest efficiency among all mechanized methods of oil production
When operating an ESP, where the concentration of solids in the pumped liquid exceeds the permissible 0.1, the pumps become clogged and the working units wear out intensively. As a result, vibration increases, water enters the motor through the mechanical seals, and the engine overheats, which leads to failure of the ESP.
The installation of a submersible electric centrifugal pump for oil production (ESP) consists of a submersible pump unit (electric motor with hydraulic protection, pump), cable line, tubing string, wellhead equipment and surface equipment: transformer and control station or complete device.
Explanation of the symbols of the installations is given using the example of U2ETsNI6-350-1100. Here: U - installation; 2 (1) - modification number; E - driven by a submersible electric motor; C - centrifugal; N - pump; I - increased wear resistance (K - increased corrosion resistance); 6 (5; 5A) - installation group; 350 - pump flow in optimal mode for water in m 3 / day; 1100 is the pressure developed by the pump in meters of water column.
ESP units can produce formation fluid with a hydrogen sulfide content of up to 1.25 g/l, and a conventional version with a hydrogen sulfide content of no more than 0.01 g/l. UECNI installations can work with media where the content of mechanical impurities reaches 0.5 g/l. Conventional installations - with a mechanical impurity content of less than 0.1 g/l.
Group 5 installations are intended for the operation of wells with an internal casing diameter of at least 121.7 mm, group 5A - 130.0 mm, group 6 - 144.3 mm, and UESN6-500-1100 and UESN6-700-800 installations - with a diameter of at least 148.3mm.
ESP applicability criterion:
1 The industry produces pumps for extracting liquids of 1000 m3 per day at a pressure of 900 m
3 Minimum content of produced water up to 99%
1.1 ESP ground equipment
Ground equipment includes a control station, an autotransformer, a drum with an electrical cable and wellhead equipment.
Electrical equipment, depending on the current supply circuit, includes either a complete transformer substation for submersible pumps (KTPPS), or a transformer substation (TS), a control station and a transformer.
Electricity from the transformer (or from the KTPPN) to the submersible electric motor is supplied through a cable line, which consists of a surface power cable and a main cable with an extension cord. The connection of the ground cable to the main cable of the cable line is carried out in a terminal box, which is installed at a distance of 3-5 meters from the wellhead.
The site for the placement of ground-based electrical equipment is protected from flooding during flood periods and cleared of snow in winter and must have entrances that allow free installation and dismantling of equipment. Responsibility for the working condition of the sites and entrances to them rests with the CDNG.
1.1.1 Control station
Using the control station, manual control of the engine, automatic shutdown of the unit when the liquid supply is stopped, zero protection, protection against overload and shutdown of the unit in the event of short circuits are carried out. During operation of the unit, a centrifugal current pump sucks liquid through a filter installed at the pump inlet and forces it through pump pipes to the surface. Depending on the pressure, i.e. liquid lifting heights, pumps with different numbers of stages are used. A check valve and drain valve are installed above the pump. The check valve is used to maintain the tubing, which makes it easier to start the engine and control its operation after starting. During operation, the check valve is held in the open position by pressure from below. The drain valve is installed above the return valve, and is used to drain fluid from the tubing when lifting them to the surface.
1.1.2 Autotransformer
A transformer (autotransformer) is used to increase the voltage from 380 (field network) to 400-2000 V.
The transformers are oil cooled. They are designed for outdoor use. On the high side of the transformer windings, fifty taps are made to supply the optimal voltage to the electric motor, depending on the cable length, motor load and mains voltage.
Switching taps is carried out with the transformer completely turned off.
The transformer consists of a magnetic core, high voltage and low voltage windings, a tank, a cover with inputs and an expander with an air dryer.
The transformer tank is filled with transformer oil having a breakdown voltage of at least 40 kW.
On transformers with a power of 100 - 200 kW, a thermosyphon filter is installed to clean transformer oil from aging products.
Mounted on the tank cover:
HV winding tap switch drive (one or two);
Mercury thermometer for measuring the temperature of the upper layers of oil;
Removable HV and LV bushings, allowing replacement of insulators without lifting the removable part;
Conservator with oil level indicator and air dryer;
Metal box to protect inputs from dust and moisture.
An oil seal air dryer is designed to remove moisture and clean industrial pollution air entering the transformer when temperature fluctuations oil level
1.1.3 Wellhead equipment
Wellhead fittings are designed to divert production from the well to the flow line and seal the interpipe space.
The wellhead fittings of a well prepared for launching an ESP are equipped with pressure gauges, a check valve on the line connecting the annulus with the discharge, a choke chamber (if technologically feasible) and a pipe for testing. Responsibility for the implementation of this point lies with the CDNG.
The wellhead fittings, in addition to the functions performed in all production methods, must ensure the tightness of the reciprocating polished rod moving in it. The latter is a mechanical connection between the rod column and the head of the SK balancer.
Wellhead fittings, manifolds and flow lines with complex configurations complicate the flow hydrodynamics. Near-well equipment located on the surface is relatively accessible and can be relatively easily cleaned of deposits, mainly by thermal methods.
The wellhead fittings of wells through which water is pumped into the formation are subjected to hydraulic testing in the manner established for Christmas tree fittings.
1.2 Underground ESP equipment
Underground equipment includes tubing, pumping unit and eclectic armored cable.
The submersible pumping unit is lowered into the well via tubing and consists of a centrifugal multistage pump, a submersible electric motor and a protector.
The pump and protector motor shafts are connected by couplings.
1.2.1 Tubing
Tubing tubing is used in the operation and repair of oil and gas wells, as well as wells for other purposes.
Nominal outer diameter of tubing pipes: 60; 73; 89; 114 mm
Outer diameter: 60.3; 73.0; 88.9; 114.3 mm
Wall thickness: 5.0; 5.5; 6.5; 7.0 mm
Strength groups: D, K, E
In terms of accuracy and quality, tubing is manufactured in two versions A and B by type: smooth according to GOST 633-80, TU 14-161-150-94, TU 14-161-179-97, API 5ST;
with ends set outward according to TU 14-161-150-94, TU 14-161-173-97,
API 5CT; smooth, highly airtight according to GOST 633-80, TU 14-161-150-94, TU 14-161-173-97; smooth with a sealing unit made of polymer material according to TU 14-3-1534-87; smooth, smooth, highly airtight with increased ductility and cold resistance according to TU 14-3-1588-88 and TU 14-3-1282-84;
smooth, highly hermetic and with outward-set ends, corrosion-resistant in active hydrogen sulfide-containing environments, having increased corrosion resistance during hydrochloric acid treatment and being cold-resistant down to a temperature of minus 60°C according to TU 14-161-150-94, TU 14-161-173-97.
Types of threaded connections:
Smooth pipes with triangular threads and couplings;
Pipes with exposed ends with triangular threads and couplings (B);
Smooth, highly airtight pipes with trapezoidal threads and couplings (NKM);
Pipes with exposed ends, trapezoidal threads, couplingless (NKB).
Threaded connections of pump-compressor pipes provide:
Passability of columns in wellbores of complex profile, including in intervals of intense curvature;
Sufficient strength for all types of loads and the necessary tightness of connections of pipe columns;
Required wear resistance and maintainability.
The pump and compressor pipes are connected to each other using coupling threaded connections. Pump and compressor pipes are manufactured in accordance with GOST 633-80 and technical specifications. In terms of accuracy and quality, they are manufactured in two versions A and B.
Tubing pipes are used during the operation of oil and gas wells to transport liquids and gases inside casing strings, as well as for repair and hoisting operations.
Distinctive features
The traceability system ensures that 100% of the tubing always meets the quality and required specifications.
Pump and compressor pipes are manufactured in the following designs and their combinations:
Highly sealed;
Cold resistant;
Corrosion resistant;
With ends set outward;
With sealing unit made of polymer material;
With distinctive coupling markings;
Standard version.
1.2.1.1 Calculation of the diameter of tubing pipes
The diameter of tubing is determined by their throughput capacity and the possibility of joint placement of pipes with couplings, a pump and a round cable in the well. The diameter of the tubing is selected according to the well flow rate, based on the condition that the average flow rate in the pipes should be within the range V av = 1.2--1.6 m/s, with a lower value taken for small flow rates. Based on this, the area of the internal tubing channel is determined, m2,
and internal diameter, cm,
where Q is the well flow rate, m 3 /day;
V SR -- selected average speed value. V CP= 1.5.
Based on the nearest internal diameter, the standard tubing diameter is selected (Table 1.1). If the difference turns out to be significant, then V with p is adjusted:
where F int is the area of the internal channel of the selected standard tubing.
Table 1.1. Characteristics of tubing
|
Nominal pipe diameter, mm |
Outer diameter D, mm |
Wall thickness d, mm |
Outer diameter of coupling D m, mm |
Weight 1 lm, kg |
Thread height h, mm |
Thread length to main plane L, mm |
|
1.2.2 Submersible centrifugal pumps
The scope of application of centrifugal pumps in oil production is quite large: flow rate 40-1000 m 3 /day; by pressure 740-1800 and (for domestic pumps).
These pumps are most effective when operating in wells with high flow rates.
However, for ESP there are limitations due to well conditions, for example, high gas factor, high viscosity, high content of mechanical impurities, etc.
The creation of pumps and electric motors in a modular design makes it possible to more accurately select the ESP to the characteristics of the well in terms of flow rates and pressures.
All these factors, taking into account economic feasibility, must be taken into account when choosing methods for operating wells.
Submersible pump installations are lowered into the well using tubing of the following diameters: 60 mm at a liquid flow rate Q No. of up to 150 m 3 /day, 73 mm at 150< Q» < 300 м 3 ,- сут. 89 мм при Q e >> 300 m 3 /day. The calculated characteristics of the ESP are given for water, and for specific liquids (oil) they are specified using correlating coefficients.
Obviously, it is advisable to select a pump based on flow rates and pressures in the area of greatest efficiency and minimum required power. ECNC units can handle liquids containing up to 1.25 g/l H,S, while conventional units can handle liquids containing up to 0.01 g/l H:S.
Conventional pumps are recommended for wells containing up to 0.1 g/l of mechanical impurities in the pumped liquid; pumps with increased wear resistance - for wells with a content of mechanical impurities in the pumped liquid of more than 0.1 g/l, but not more than 0.5 g/l; pumps with increased corrosion resistance - for wells with a hydrogen sulfide content of up to 1.25 g l and a pH value of 6.0-8.5.
To select aggressive formation fluids or fluids with a significant content of mechanical impurities (sand), diaphragm well pumping units are used. They are electrically driven positive displacement pumps.
Submersible centrifugal pump installations
IN installation of ESP includes a submersible electric pump unit, which combines an electric motor with hydraulic protection and a pump; cable line lowered into the well on lifting tubing pipes 4; wellhead equipment type OUEN 140-65 or Christmas tree fittings
AFK1E-65x14; control station and transformer, which are installed at a distance of 20-30 from the wellhead. Electricity is supplied to the engine via a cable line. The cable is secured to the pump and tubing pipes with metal belts. Check valves and drain valves are installed above the pump. The pumped fluid from the well enters the surface through the tubing string.
The submersible electric pump, electric motor and hydraulic protection are connected to each other by flanges and studs. The pump, motor and protector shafts have splines at the ends and are connected by splined couplings.
Depending on the transverse size of the submersible electric pump unit, the installations are divided into three conditional groups: 5, 5A and 6 (Table 1.2).
Let's consider the designation of the installation using the example of 1U9ETsN5A-250-1400:
1 - serial number of the installation modification; U - installation; 9 - serial number of pump modification; E - drive from a submersible electric motor; C - centrifugal; N - pump; 5A - pump group; 250 - supply, m 3 / day;
1400 - head, m.
Sectional, multi-stage submersible pump with small diameter working stages - impellers and guide vanes. Submersible pumps used in the oil industry have from 145 to 400 stages.
The pump consists of one or more sections connected to each other using flanges. The section has a length of up to 5.5 m.
Table 1.2
The length of the pump is determined by the number of working stages and sections, which depends on the pump parameters - flow and pressure. A stage package is inserted into the pump housing, which consists of assembled impellers and guide vanes. The impellers are mounted on the shaft on a longitudinal feather key along a running fit and can be moved in the axial direction. The guide vanes are clamped in the housing between the base and the upper nut.
A pump base with inlet holes and a filter mesh is attached to the bottom of the housing, through which liquid from the well flows to the first stage of the pump. At the top of the pump there is a fishing head with a check valve installed in it, to which the tubing pipes are attached.
1.2.2.1 Determination of the required ESP pressure
The required pressure is determined from the equation of the conditional characteristics of the well:
where h ST is the static fluid level in the well, m; -- depression, m; h tr -- pressure loss due to friction in pipes; h Г -- difference in geodetic elevations of the separator and the wellhead; h c -- pressure loss in the separator.
Depression is determined when the exponent of the inflow equation is equal to one:
where K is the well productivity coefficient, m 3 /day*MPa; - liquid density, kg/m3; g=9.81 m/s 2 .
Friction pressure loss in pipes, m, is determined by the formula:
where L is the depth of pump descent, m.
h is the depth of immersion of the pump under the dynamic level;
Distance from well to separator, m; - coefficient of hydraulic resistance.
The coefficient is determined depending on the number and relative smoothness of the pipes:
where is the kinematic viscosity of the liquid, m 2 /s;
where is the roughness of the pipe walls, taking equal to 6.1 mm for pipes uncontaminated with deposits of salts and paraffin.
The way to determine it is to calculate it using the Reynolds number, regardless of the roughness:
Head loss to overcome pressure in the separator:
where p c is the excess pressure in the separator.
Substituting the calculated values and pre-specified ones into formula (4), we will find the required pressure for a given well.
Selecting a pump:
ETsNI5-130-1200
Nominal flow: 130 m 3 /day
Head:1165 m
Number of steps - 260
According to table 1.3. select an ESP with the number of stages
Table 1.3. Characteristics of submersible centrifugal pumps
|
Pump code |
Nominal |
Workspace |
Number of steps |
Weight, kg |
||||
|
Supply, m 3 /day |
Supply m3/day |
|||||||
|
ETsNI5-40-850 ETsNI5-40-950 |
||||||||
|
ETsNI5-80-1550 |
||||||||
|
ESP5-130-1200 ETsNI5-130-1200 |
||||||||
|
ETsNI5A-100-1350 |
||||||||
|
ESP5A-160-1100 ESP5A-160-1400 |
||||||||
|
ESP5A-250-800 ESP5A-250-1000 |
||||||||
|
ESP5A360-600 ESP5A-360-700 ESP5A-360-850 |
||||||||
|
ETsNI6-100-900 ESP6-100-1500 ETsNI6-100-1500 |
||||||||
|
ETsNI6-160-750 ESP6-160-1100 ETsNI6-160-1100 ESP6-160-1450 ETsNI6-1601450 |
||||||||
|
ETsNI6-250-800 ESP6-250-1050 ETSNi6-250-1050 ESP6-250-1400 |
||||||||
|
ESP-6-500-450 ETsNI6-500-450 ETsNI6-500-750 |
Table 1.4. ESP parameters in modular design
|
Pump code |
Nominal |
Workspace |
Number of stupas |
kW |
||||
|
Supply, m 3 /day |
Supply, m 3 /day |
|||||||
|
ETsNM5-50-1300 ETsNMK5-50-1300 ETsNM5-50-1700 ETsNMK5-50-1700 |
||||||||
|
ETsNM5-80-1200 ETsNMK5-80-1200 ETsNM5-80-1400 ETsNMK5-80-1400 ETsNM5-80-1550 ETsNMK5-80-1550 ETsNM5-80-1800 ETsNMK5-80-1800 |
||||||||
|
ETsNMK5-125-1000 ETsNM5-125-1000 ETsNMK5-125-1200 ETsNM5-125-1200 ETsNMK5-125-1300 ETsNM5-125-1300 ETsNMK5-125-1800 ETsNM5-125-1800 |
||||||||
|
ETsNM5-200-800 ETsNM5-200-1000 ETsNM5-200-1400 |
||||||||
|
ETsNM5A-160-1450 ETsNMK5A-160-1450 ETsNM5A-160-1600 ETsNMK5A-160-1600 ETsNM5A-160-1750 ETsNMK5A-160-1750 |
||||||||
|
ETsNM5A-250-1000 ETsNMK5A-250-1000 ETsNM5A-250-1100 ETsNMK5A-250-1100 ETsNM5A-250-1400 ETsNMK5A-250-1400 ETsNM5A-250-1700 ETsNMK5A-250-1700 |
||||||||
|
ETsNM5A-400-950 ETsNMK5A-400-950 ETsNM5A-400-1250 ETsNMK5A-400-1250 |
||||||||
|
ETsNM5A-500-800 ETsNMK5A-500-800 ETsNM5A-500-1000 ETsNMK5A-500-1000 |
||||||||
|
ETsNM6-250-1400 ETsNMK6-250-1400 ETsNM6-250-1600 ETsNMK6-250-1600 |
||||||||
|
ETsNM6-500-1150 ETsNMK6-500-1150 |
||||||||
|
ETsNM6A-800-1000 ETsNMK6A-800-1000 |
||||||||
|
ETsNM6A-1000-900 ETsNMK6A-1000-900 |
Centrifugal pump
The centrifugal pump is driven by a special oil-filled submersible asynchronous three-phase alternating current electric motor with a vertical squirrel-cage rotor of the PED type.
The motor consists of a stator, rotor, head shaft and base. The stator housing is made of steel pipe with threaded ends for connecting the motor head and base.
The stator is assembled from active and non-magnetic laminated sheet metal with grooves in which the winding is located. The winding phases are connected in a star.
The output ends of the stator winding are connected to the cable through a special insulating plug coupling for the cable entry.
The motor consists of a stator, rotor, head shaft and base.
The stator housing is made of steel pipe with threaded ends to connect the motor head and base.
The engine is filled with a special low-viscosity oil for cooling and lubrication (with high dielectric strength).
The stator is assembled from active and non-magnetic laminated sheet metal with grooves in which the winding is located. The winding phases are connected in a star. The output ends of the stator winding are connected to the cable through a special insulating plug coupling for the cable entry.
The squirrel-cage multi-section motor rotor is made up of magnetic cores alternating with plain bearings. A channel is made along the shaft axis to ensure oil circulation in the engine cavity. Copper rods are placed in the grooves of the cores, welded at the ends with short-circuiting rings.
The sectional electric motor consists of two
sections - upper and lower, each of which has the same main components as a single-section engine, but structurally these components are made differently.
The protector has two chambers filled with the working liquid of the electric motor. The chambers are separated by an elastic element - a rubber diaphragm with mechanical seals. The protector shaft rotates in three bearings and rests on a hydrodynamic heel, which perceives axial loads. The pressure in the protector is equalized with the pressure in the well through a check valve located in the lower part of the protector.
The compensator consists of a chamber formed by an elastic element - a rubber diaphragm, filled with the working fluid of the electric motor.
The cavity behind the diaphragm communicates with the well through holes
The cable line that supplies electricity to the electric motor of a submersible centrifugal electric pump consists of a main power cable, a flat cable spliced with it, and a cable entry coupling for connecting to the electric motor. Depending on the purpose, the cable line may include a KPBK cable (as the main one).
1.2.2.2 Calculation and selection of a centrifugal pump
The selection of a pump for a given flow, the required pressure and the diameter of the well production string is made according to the characteristics of submersible centrifugal pumps (Table 1.2. or Table 1.3.). It must be borne in mind that, in accordance with the characteristics of the ESP, the pump pressure increases with a decrease in flow, and the efficiency has a pronounced maximum.
Considering that the tabular characteristics (Table 1.3. or Table 1.4.) are built for water, the tabulated pressure values should be changed in accordance with the density of the real liquid according to the ratio:
where N in is the table value of the ESP pressure; r in - density of fresh water; .rz - density of real liquid.
To combine the characteristics of the well and the pump, two methods are used.
1. At the outlet of the well, a fitting is installed, to overcome the additional resistance of which the excess pressure of the pump DH=H-H c is used. However, this method is simple, but not economical, as it reduces the efficiency of the pump and the installation as a whole.
2. The second method involves disassembling the pump and removing unnecessary stages. This method is labor-intensive, but the most economical, since the efficiency of the pump does not change. The number of stages that must be removed from the pump to obtain the required pressure is equal to
where N w is the pump pressure according to its characteristics, corresponding to the well flow rate; N s - required well pressure; z -- number of pump stages.
1.2.3 Submersible motors
Submersible electric motors (SEM) are used as a drive for ESPs; they are produced in size groups: 103 and 117 mm, with a power from 12 to 300 kW.
A wide range of manufactured SEDs of varying power allows you to select the most optimal “motor-pump” combination to ensure the installation operates with the highest possible efficiency. Manufacturing technology ensures high quality and reliability of submersible electric motors produced by JSC BENZ.
The stator is made with a closed groove, which increases the cleanliness of the internal cavity of the engine and allows the successful use of groove insulation in the form of a tube. The electric motor rotor uses original bearings that are mechanically secured against rotation and at the same time retain the ability to easily move along the shaft axis.
The use of special electrical materials allows the operation of submersible motors at formation fluid temperatures up to 120 °C, and in high-heat-resistant versions - up to 150 °C.
After assembly on special stands where the quality of individual components is controlled, the electric motor is tested at the station, under conditions close to real ones, including heating to operating temperatures. 100% of engines are tested, after testing they are all disassembled and thoroughly checked. The insulation resistance is monitored using the polarization index.
The submersible electric motor is an integral part of the submersible pump unit, which also includes a pump, drain and check valves. The main condition for long-term uninterrupted operation of a submersible electric motor is its hydraulic protection, since during operation it is completely immersed in the pumping medium. The liquid can be very different - from water, a mixture of salt and water to oil and its mixtures with water and gases. Thus, the environment is often aggressive, leading to rapid corrosion. That is why, in the production of a submersible electric motor, hydraulic protection is given greatest attention. Submersible electric motors for oil production are produced in a wide variety of designs, with power ranging from 10 to 1600 hp. So how does the engine operate at temperatures up to 90? There are special heat-resistant versions of the electric motor (up to +140? C). Since the motor operates completely immersed in liquid, one of the main conditions for reliable operation is its tightness. The engine is filled with special oil, which serves both to cool the engine and lubricate parts.
The electric motor uses:
stator with straightening of internal boring;
heat-resistant current lead blocks (up to +220 (C) with fixation;
rotor bearings made of non-magnetic cast iron;
friction pair in housing parts, rotor bearings, heat-treated steel - metal fluoroplastic;
rotor shaft with central and axial holes, there is an oil circulation circuit;
bushings for rotor bearings and bearings of housing parts having axial holes for lubrication.
1.2.3.1 Calculation and selection of electric motor
The required (net) engine power, kW, is determined by the formula:
where is the efficiency of the pump according to its operating characteristics, and is the highest density of the pumped liquid.
Considering that the transmission efficiency from the engine to the pump (through the protector) is 0.92--0.95 (sliding bearings), we determine the required engine power:
We select the nearest larger power standard size of the electric motor according to Table 1.5, taking into account the diameter of the production string (140mm-103mm; 146mm-117mm; 168mm-123mm).
The power reserve is necessary to overcome the high starting torques of the ESP.
Power-40kW
Voltage - 1000V
Current strength - 40A
cooling speed - 0.12m
temperature -55C
length-6.2m
weight-335kg
Table 1.5. Characteristics of submersible motors
|
Electric motor |
Nominal |
Liquid cooling rate, m/s |
Ambient temperature, ° C |
Weight, kg |
||||||
|
power, kWt |
Voltage, V |
Current strength, A |
||||||||
1.2.4 Cable line
The cable line provides power supply to the electric motor. The cable is attached to the tubing with metal wheels. Along the length of the pump and protector, the cable is flat, attached to them with metal wheels and protected from damage by casings and clamps. Check and drain valves are installed above the pump sections. The pump pumps fluid out of the well and delivers it to the surface through the tubing string.
The cable runs from the top of the motor, to the side of the pump/seal, and is attached to the outside surface of each tubing along the entire length of the lift string from the motor to the wellhead and then to the electrical distribution box. The cable consists of three cores of protected and insulated continuous wire. Due to limited clearance around the pump/seal, a flat cable is used between the motor and the tubing above the pump. At this point it is spliced with a less expensive round cable that extends to the mouth. The cable may have a metal sheath to protect it from damage.
Cable line, i.e. a cable wound on a drum, to the base of which an extension is attached - a flat cable with a cable entry sleeve. Each cable core has an insulation layer and a sheath, cushions made of rubberized fabric and armor. Three insulated cores of a flat cable are laid parallel in a row, and a round cable is twisted along a helical line. The cable assembly has a unified cable entry coupling K 38, K 46 of the round type. In a metal casing, the couplings are hermetically sealed using a rubber seal, and tips are attached to the conductive conductors.
The cable is secured to the pipes with steel belts at a distance of 200-250 mm from the upper and lower ends of the coupling. After lowering two or three pipes, install a check valve.
A cable twisted around pipes will increase the overall diametrical size of the submersible part of the installation and may suffer mechanical damage during descent.
1.2.4.1 Calculation and selection of electrical cable
The cross-section of the cable core is selected according to the rated current of the electric motor, based on the density i of the operating current in this cable:
where I is the rated current of the electric motor, A; i=5 - permissible current density, A/mm 2.
When choosing a cable, you should take into account the ambient temperature and pressure, and the permissible voltage (Table 1.5.).
If there is dissolved gas in the produced liquid, preference should be given to a cable with polyethylene and elastoplastic insulation, since it does not absorb gas dissolved in oil and is not damaged by it when rising to the surface. If there are corrosive agents in the well, preference is given to a cable with fluoroplastic insulation (Table 1.5.).
Power losses in the cable are determined by the formula:
where I is the operating current in the electric motor, A; L k - cable length, m; R - cable resistance, Ohm/m,
where is the resistivity of copper at the temperature coefficient for copper; t 3 =50 0 C - temperature at the intake at the pump inlet; S-area cross section cable cores.
The total length of the cable should be equal to the depth of the pump run plus the distance from the well to the control station and a small margin for cable repair (l p = 100m):
Table 1.5 Main characteristics of cables
|
Number x cross-sectional area of cores, mm 2 |
Maximum external dimensions, mm |
Nominal construction |
Estimated weight, kg/km |
Operating voltage, V |
|||
|
Basics |
control |
||||||
|
300 and multiples |
|||||||
|
100 and times |
|||||||
|
100 and times |
|||||||
2. Safety precautions and environmental protection during the operation of ESP wells
The main safety provisions when operating wells with electric centrifugal pumping units are the fencing of the moving parts of the pumping machine and the correct implementation of the requirements for repairs. With the introduction of a single-pipe system for collecting and transporting oil well products, serious demands are placed on the wellhead equipment. At relatively high wellhead pressures (2.0 MPa and above), the equipment must have a sufficient safety margin. It is necessary to operate only standard wellhead equipment, tested and accepted for serial production, in particular, wellhead seals with a self-aligning head type SUS1-73-25, designed for a working pressure of 2.5 MPa, and SUS2-73-40 for a pressure of 4.0 MPa .
When installing and operating pumping machines, the following basic safety requirements are imposed:
1. The rocking machine must be installed under the guidance of an experienced foreman or foreman using installation tools or a crane.
2. All moving parts of the machine must be guarded.
3. When the balancer head is in the lower position, the distance between the traverse suspension of the stuffing box rod and the wellhead seal must be at least 20 cm.
4. It is forbidden to turn the gear pulley manually and slow it down by placing a pipe, crowbar or other objects.
5. It is forbidden to remove the V-belt using levers: install and remove the belt by moving the electric motor.
6. Work related to inspection or replacement of individual parts of the machine must be performed when the machine is stopped.
7. Before starting the pumping machine, you should make sure that the machine is not on the brake, that the guards are installed and secured, and that there are no unauthorized persons in the danger zone.
8. Before you start repair work At the installation, the drive must be turned off, and a poster “Do not turn on people working” should be attached to the starting device. On wells with automatic and remote control, the starting device must have a shield with the inscription “Attention! The start is automatic."
When servicing the electric drive, personnel must wear dielectric gloves. The electric centrifugal pumping unit must be grounded before commissioning. As a grounding conductor for electrical equipment, it is necessary to use a well conductor, which must be connected to the machine frame by two grounding conductors (each with a cross-section of 50), welded at different points of the conductor and frame, accessible for inspection. The grounding conductor can be round, flat, angular or other steel profile, except rope. To protect against damage electric shock When servicing the rocking machine, insulating stands are used.
Conclusion
ESPs are designed for pumping formation fluid from oil wells and are used to force fluid withdrawal. The installations belong to product group II, type I according to GOST 27.003-83.
ESP installations of electric centrifugal pumps (ESP), as a rule, are used in high-yield wells, providing the highest efficiency among all mechanized methods of oil production.
The industry produces pumps with pressures ranging from 450-1500m.
The pressure is determined by the formula:
We determine power:
As a result of the calculations made, we obtain:
Pump: ETsNI5-130-1200
Nominal feed:130
Number of steps - 260
Electric motor: PED40-103
Conclusion
Having done this coursework, I consolidated and deepened the acquired knowledge and applied it to solving specific theoretical and practical problems; received additional skills in working with reference and scientific literature.
Bibliography
1.Andreev V.V. Urazakov K.R. “Handbook on oil and gas production” - 1998
2. Fundamentals of oil and gas business: Textbook. E.O. Antonova, G.V. Krylov, A.D. Prokhorov, O.A. Stepanov -M.: 2003.-307 p.: ill.
3. Korshak A.A., Shammazov A.M. Fundamentals of oil and gas business: Textbook.-2nd ed., additional, and corrected. -Ufa: Design PolygraphService, 2002.-544p.
4. Mishchenko I.T. Well oil production. Textbook for universities. - M.: Federal State Unitary Enterprise Publishing House "Oil and Gas" Russian State University of Oil and Gas named after. THEM. Gubkina, 2003.
5. Molchanov G.V., Molchanov A.G. Cars. Drilling equipment. Directory in 2 volumes. /Abubakirov V.F., Arkhangelsky V.L. etc./ -- M.: Nedra, 2000.
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OIL PRODUCTION ESP
4.3.1. General information on the operation of wells,
equipped with electric submersible installations
centrifugal pumps (ECP)
Installations of electric submersible centrifugal pumps belong to the class of rodless installations and play a decisive role in the Russian oil industry in terms of the volume of oil produced. They are designed for the operation of production wells of different depths with different properties of the produced products: anhydrous low-viscosity and medium-viscosity oil; water cut oil; a mixture of oil, water and gas. Naturally, the operating efficiency of ESP wells can vary significantly, because the properties of the pumped product affect the output parameters of the installation.
In addition, ESPs have undeniable advantages over rod units, not only due to the transfer of the drive motor to the bottom hole and the elimination of the rod string, which significantly increases the efficiency of the system, but also due to a significant range of working feeds (from several tens to several hundred m3/day ) and pressures (from several hundred to several thousand meters) with a relatively high installation mean time between failures.
The selection of the standard size and configuration of the ESP for a specific well, the calculation of the expected technological operating mode of the well and the parameters of the submersible equipment are carried out both by a software package integrated into the corporate database of NPK ALPHA, and according to the methodology chosen by the chief technologist (head of the technical and technical department) of the NGDU and adapted to conditions of a given field (formation).
Calculation of the optimal operating mode of the well is carried out by the geological service of the NGDU. Based on the parameters specified by the geologist, the technological service selects the standard size of the ESP and the parameters of the submersible equipment in the Autotechnological PC, adapted to the conditions of the oil and gas production management fields.
Responsibility for calculating the expected flow rate at the expected dynamic level, the reliability of the information and the completeness of entering the results of well testing into the NPK Alfa database lies with the leading geologist of the CDNG. Responsibility for the correct selection of the pump size and determination of the descent depth lies with the TsDNG technologist.
When calculating the selection of an electric submersible pump, it is necessary to take into account:
– use of the actual productivity coefficient, optimal fluid extraction from the well, subject to the condition of not exceeding the maximum permissible drawdown on the reservoir and the field development project;
– the specific gravity of pumping out the kill fluid when putting it into operation to ensure the supply of reservoir fluid at the expected dynamic level, buffer pressure and friction losses in the lift and oil-gathering manifold to the booster station, ESP operation in the optimal mode zone (0.8÷1.2 Q nom);
^t
Possibility of changing ESP performance using
control stations with frequency converter (CSCP).
For wells with a water content in the produced product of more than 90%, the immersion under the dynamic level of the ESP should be no more than 400 meters.
The critical flow rates (depressions) of each specific well in waterfloat and gas-oil deposits are determined by the development department of the Oil and Gas Production Department (geologist of the Center for Oil and Gas Production) based on the experience of operating wells with identical geological and technical characteristics of the bottomhole zone.
At the location where the submersible unit is suspended, the curvature of the wellbore should not exceed:
For ESP-5 size according to the formula: a = 2arcsin ^P s: ,
where: a is the curvature of the wellbore at the location where the ESP is suspended, degrees/10 m;
S- the gap between the internal diameter of the casing and the maximum diametrical dimension of the installation, m;
L- installation length from the lower end of the compensator to the upper end of the pump, m;
For ESP-5, with a production string diameter of 146 mm - 6 minutes per 10 meters, with a production string diameter of 168 mm - 12 minutes per 10 meters;
For ESP-5A, with a production string diameter of 146 mm - 3 minutes per 10 meters, with a production string diameter of 168 mm - 6 minutes per 10 meters;
If there are no areas with the specified curvature intensity, a section with the minimum value for a given well is selected and agreed upon with the chief engineer of the oil and gas department.
If there are areas in the well with a curvature intensity exceeding 20/10 m, the weekly application from the oil and gas production department must indicate the need to equip an ESP for this well with a submersible motor with a diameter of 103 mm (for submersible motors with a power of up to 45 kW, inclusive).
In the operating area of the submersible installation, the deviation of the wellbore from the vertical should not exceed 60 degrees.
The maximum hydrostatic pressure in the ESP operating area should not exceed 20 MPa (200 kgf/cm2).
The design of the tubing string must ensure the strength of the suspension at a given running depth and well design.
The immersion of the pump under the dynamic level is determined by the content of free gas in the well production (in the formation fluid) under pump intake conditions: up to 25% - without a gas separator, 25-55% - with a gas separator, up to 68% - with a gas separator-dispersant, up to 75 % - with a domestic or imported multiphase system.
Technical requirements for the pumped medium - formation fluid (mixture of oil, produced water, mineral impurities and petroleum gas):
The maximum density of the water-oil mixture is 1,400 kg/m 3 ;
Gas factor (Gf) - up to 110 m 3 /m 3;
– maximum content of produced water – 99%;
– pH value of produced water (pH) – 6.0–8.5;
– temperature of the pumped liquid:
– for standard execution – up to +90 °С;
– for heat-resistant version – up to +140 °C;
– for standard version – up to 100 mg/l;
– for wear-resistant design – up to 500 mg/l;
In the ESP suspension kit, it is allowed to use additional auxiliary elements only factory-made or manufactured according to the standards of Surgutneftegaz OJSC.
The maximum temperature of the pumped liquid in the operating area of the submersible unit should not exceed the rating data of the motor and cable extensions used at Surgutneftegas OJSC. With the calculated expected values of operating conditions at the pump intake at a temperature of more than +120 °C, the TsDNG technologist in the application for TsBPO EPU equipment indicates the necessary equipment for heat resistance.
The main provisions for selecting an ESP are given below:
1. Density of the mixture in the section “well bottom - pump intake”:
■ With
(p b + p(1 - b)) (1 - F) + pF.
where: ρ n– density of separated oil, kg/m3, ρ V– formation water density, ρ G– gas density under standard conditions, G– current volumetric gas content, b– water cut of formation fluid.
2. Bottomhole pressure at which the specified well flow rate is ensured:
Where: R pl- reservoir pressure,
Q– specified well flow rate,
K prod– well productivity coefficient.
3. Depth of dynamic level at a given fluid flow rate:
Oil production equipment and technology
4. Pressure at the pump intake, at which the gas content at the pump inlet does not exceed the maximum permissible for a given region (for example: F = 0.15):
P = P. (I - G).,
Where To - degree of degassing curve.
5. Pump suspension depth:
Where: B– volumetric coefficient of oil at saturation pressure, b– volumetric water cut of products,
14. Gas work in the “bottomhole – pump intake” section:
Quantities with the index " boof" refer to the section of the wellhead and are "buffered" by pressure, gas content, etc.
16. Required pump pressure:
Where: L din– depth of location of the dynamic level;
P buffer– buffer pressure;
P G1– gas operating pressure in the section “bottom hole – pump intake”;
P G2– gas operating pressure in the “pump discharge – wellhead” section.
17. Based on the pump flow at the inlet, the required pressure (pump pressure) and the internal diameter of the casing, we select the standard size of a submersible centrifugal (or screw, diaphragm) pump and determine the values that characterize the operation of this pump in optimal mode (flow, pressure, efficiency, power ) and in supply mode equal to 0 (pressure, power).
18. Coefficient of change in pump flow when operating on an oil-water-gas mixture relative to the water characteristic:
where: ν – effective viscosity of the mixture;
Q o IN– optimal pump flow on water.
24. Coefficient of change in pump pressure due to the influence of viscosity:
Where h- pressure of one stage of the selected pump.
WithG
The Z number is rounded to a higher integer value and compared to the standard number of stages of the selected pump size. If the calculated number of stages turns out to be greater than that specified in the technical documentation for the selected pump size, then you must select the next standard size with a larger number of stages and repeat the calculation starting from point 17.
If the estimated number of stages turns out to be less than that specified in the technical specifications, but their difference is no more than 5%, the selected pump size is left for further calculation. If the standard number of stages exceeds the calculated one by 10%, then a decision is necessary to disassemble the pump and remove the extra stages. Further calculations are carried out from paragraph 18 for new values of the operating characteristic.
28. Pump efficiency taking into account the influence of viscosity, free gas and operating mode:
V - /Ci." K w " fCijr,
Where ri o6- maximum pump efficiency for water characteristics.
Oil production equipment and technology
29. Pump power:
where: η PED– efficiency of the submersible electric motor,
cosϕ – engine power factor at operating temperature.
31. We check the pump and submersible motor for the possibility of pumping out heavy liquid (killing liquid) during well development:
Rgl=Rgl
1_. р +р +р
■- P buff G zab^ PL"
where ρ GL– density of the killing fluid.
We calculate the pump pressure when developing a well:
Magnitude N GL is compared with the passport water characteristics. We determine the pump power when developing a well:
Power consumed by a submersible electric motor during well development:
32. We check the installation for the maximum permissible temperature at the pump intake:
T> [T]
Where [ T] – maximum permissible temperature of the pumped liquid at the intake of the submersible pump.
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33. We check the heat sink installation according to the minimum permissible coolant velocity in the annular section formed by the inner surface of the casing at the installation site of the submersible unit and the outer surface of the submersible motor, for which we calculate the flow rate of the pumped out liquid:
Where: F = 0.785 ■ - annular area; D- internal diameter of the casing; cf is the outer diameter of the motor.
If the flow rate of the pumped liquid is greater [W](Where [W]- minimum permissible speed of the pumped liquid), the thermal regime of the submersible motor is considered normal.
If the selected pumping unit is not able to extract the required amount of kill fluid at the selected suspension depth, it (the suspension depth) is increased by liters! = 10 - 100 m, after which the calculation is repeated starting from step 5. Magnitude &L depends on the availability of time and computing capabilities of the consumer.
After determining the suspension depth of the pump unit using an inclinogram, the possibility of installing the pump at the selected depth is checked (by the rate of curvature gain per 10 m of penetration and by the maximum angle of deviation of the well axis from the vertical). At the same time, the possibility of lowering the selected pumping unit into a given well and the most dangerous sections of the well, the passage of which requires special care and low lowering speeds during PRS, are checked.
After the final selection of the depth of descent of the downhole unit, the type of cable (based on operating current and temperature of the pumped out liquid) and the size of the transformer (based on operating current and voltage) are selected. After completing the selection of equipment, the power consumed by the installation is determined:
NnoTP = N n s n + AN KAB + AN Tp,
where: aWjus= - ~ "" : - cable power loss
/ - operating current of the motor, L; L- length of current-carrying cable, m;
p t- resistance of a linear meter of cable at operating temperature, Ohm/m ■ mm 2 ;
S- cross-sectional area of the cable cores, mm 2;
D L/t = (1 - Ti) (L/tp + A AL) - power losses in the transformer,
g]tr - Transformer efficiency.
