For a long time I dreamed of writing on paper (printing on a computer) everything I know about ESPs.
I will try to tell in a simple and understandable language about the Electric Centrifugal Pump Unit - the main tool that produces 80% of all oil in Russia.

Somehow it turned out that I have been connected with them all my adult life. From the age of five, he began to travel with his father along the wells. At ten he could repair any station himself, at twenty-four he became an engineer at the enterprise where they were repaired, at thirty - deputy general director, where they are made. Knowledge on the subject in bulk - it’s not a pity to share, especially since many, many people constantly ask me about this or that regarding my pumps. In general, in order not to repeat the same thing many times in different words, I will write once, and then I will take exams;). Yes! There will be slides ... without slides in any way.

What it is.
ESP - installation of an electric centrifugal pump, it is also a rodless pump, it is also ESP, it is also those sticks and drums. UETsN - it is she (feminine)! Although it consists of them (male gender). This is such a special thing, with the help of which valiant oilmen (or rather, servicemen for oilmen) get reservoir fluid from underground - this is how we call that mulyak, which then (after undergoing special processing) is called all sorts of interesting words like URALS or BRENT. This is a whole complex of equipment, which would require the knowledge of a metallurgist, metalworker, mechanic, electrician, electronics engineer, hydraulics, cable worker, oilman, and even a little gynecologist and proctologist. The thing is quite interesting and unusual, although it was invented many years ago, and has not changed much since then. By and large, this is an ordinary pumping unit. What is unusual about it is that it is thin (the most common is placed in a well with an internal diameter of 123 mm), long (there are installations 70 meters long) and works in such filthy conditions in which a more or less complex mechanism should not exist at all.

So, as part of each ESP there are the following nodes:

ESP (electric centrifugal pump) - the main unit - all the rest protect and provide it. The pump gets the most - but he does the main job - lifting the liquid - he has such a life. The pump consists of sections, and sections of steps. The more steps, the greater the pressure that the pump develops. The larger the stage itself, the greater the flow rate (the amount of liquid pumped per unit of time). The more debit and pressure - the more it eats energy. Everything is interconnected. The pumps, in addition to flow rate and pressure, also differ in size and design - standard, wear-resistant, corrosion-resistant, wear-corrosion-resistant, very, very wear-corrosion-resistant.

SEM (submersible electric motor) The electric motor is the second main unit - it turns the pump - it consumes energy. This is a conventional (in electrical terms) asynchronous electric motor - only it is thin and long. The engine has two main parameters - power and size. And again, there are different versions of standard, heat-resistant, corrosion-resistant, especially heat-resistant, and in general - not killed (as if). The engine is filled with special oil, which, in addition to lubricating, also cools the engine, and to a heap compensates for the pressure exerted on the engine from the outside.

The protector (also called hydraulic protection) is a thing that stands between the pump and the engine - firstly, it divides the engine cavity filled with oil from the pump cavity filled with formation fluid, while transmitting rotation, and secondly, it solves the problem of equalizing pressure inside the engine and outside ( there, in general, it happens up to 400 atm, it’s about like a third of the depth of the Mariana Trench). There are different sizes and, again, all sorts of blah blah blah.

The cable is actually a cable. Copper, three-core .. It is also armored. Can you imagine? Armored cable! Of course, he will not withstand a shot even from Makarov, but on the other hand, he will withstand five or six descents into the well and will work there - for quite a long time.
His armor is somewhat different, designed more for friction than for a sharp blow - but still. The cable can be of different sections (core diameters), differs in armor (plain galvanized or stainless steel), and it also differs in temperature resistance. There is a cable for 90, 120, 150, 200 and even 230 degrees. That is, it can work indefinitely at a temperature twice the boiling point of water (note that we extract something like oil, and it doesn’t even burn sickly - but you need a cable with a heat resistance of over 200 degrees - and moreover, almost everywhere).

A gas separator (or a gas separator-dispersant, or just a disperser, or a double gas separator, or even a double gas separator-disperser). A thing that separates free gas from liquid .. rather liquid from free gas ... in short, reduces the amount of free gas at the inlet to the pump. Often, very often, the amount of free gas at the inlet to the pump is quite enough for the pump not to work - then they put some kind of gas stabilizing device (I listed the names at the beginning of the paragraph). If there is no need to install a gas separator, they install an input module, but how should the liquid get into the pump? Here. They put something in any case .. Either a module or a jeep.

TMS is a kind of tuning. Who deciphers how - thermomanometric system, telemetry .. who how. That's right (this is the old name - from 80 shaggy years) - a thermomanometric system, so we will call it names - it almost completely explains the function of the device - it measures temperature and pressure - there - right below - almost in the underworld.

There are also protective devices. This is a check valve (the most common is KOSH - a ball check valve) - so that the liquid does not drain from the pipes when the pump is stopped (it can take several hours to lift a liquid column through a standard pipe - it’s a pity this time). And when you need to raise the pump - this valve interferes - something constantly flows from the pipes, polluting everything around. For these purposes, there is a knock-out (or drain) valve KS - a funny thing - which is broken every time when it is lifted from the well.

All this economy hangs on tubing pipes (tubing pipes - fences are made of them very often in oil-rich cities). Hangs in the following sequence:
Along the tubing (2-3 kilometers) - cable, from above - KS, then KOSH, then ESP, then gazik (or input module), then protector, then SEM, and even lower TMS. The cable runs along the ESP, gas and protector to the very head of the engine. Eka. Everything is a head shorter. So - from the top of the ESP to the bottom of the TMS can be 70 meters. and a shaft passes through these 70 meters, and it all rotates ... and around - a high temperature, huge pressure, a lot of mechanical impurities, a corrosive environment .. Poor pumps ...

All pieces are sectional, sections no more than 9-10 meters long (otherwise, how can they be put into the well?) The installation is going to be directly on the well: SEM, a cable, protector, gas, pump sections, valves, pipes are fastened to it .. Yes! do not forget to attach the cable to everything with the help of blots - (such special steel belts). All this is dipped into the well and for a long time (I hope) it works there. In order to power all this (and somehow manage it), a step-up transformer (TMPN) and a control station are installed on the ground.

With such a thing, they get something that then turns into money (gasoline, diesel fuel, plastics and other garbage).

Let's try to figure it out .. how it all works, how it's done, how to choose and how to use it.

The ESP plant is a complex technical system and, despite the well-known principle of operation of a centrifugal pump, it is a combination of elements that are original in design. circuit diagram The ESP is shown in Figure 1.1.

Figure 1.1 - Schematic diagram of the ESP

The installation consists of two parts: ground and submersible. The ground part includes an autotransformer 1, a control station 2, sometimes a cable reel 3 and wellhead equipment 4. The submersible part includes a tubing string 5, on which the submersible unit is lowered into the well, an armored three-core electric cable 6, through which the supply voltage is supplied to the submersible electric motor and which is attached to the tubing string with special clamps 7. The submersible unit consists of a multi-stage centrifugal pump 8 equipped with a receiving screen 9 and a check valve 10. Often, a submersible installation kit includes a drain valve 11, through which liquid is drained from the tubing when the installation is lifted. In the lower part, the pump is articulated with a hydraulic protection unit (protector) 12, which, in turn, is articulated with a submersible motor 13. In the lower part, the motor 13 has a compensator 14.

1) A submersible centrifugal pump (Figure 1.2) is structurally a set of stages of small diameter, consisting, in turn, of impellers and guide vanes placed in the pump housing (pipe).

Figure 1.2 - Scheme of a centrifugal electric pump

Impellers made of cast iron, bronze or plastic materials are mounted on the pump shaft with a slip fit using a special key. Top part assembly of impellers (pump shaft) has a support foot (sliding bearing) fixed in the pump casing. Each impeller rests on the end surface of the guide vane. The lower end of the pump has a bearing assembly consisting of angular contact bearings. The bearing assembly is isolated from the pumped liquid and in some designs the pump shaft is sealed with a special stuffing box. The submersible centrifugal pump is made in the form of separate sections with a large number of stages in each section (up to 120), which makes it possible to assemble the pump with the required pressure. The domestic industry produces pumps of conventional and wear-resistant design. Wear-resistant pumps are designed for pumping liquids from wells with a certain amount of mechanical impurities (indicated in the pump certificate). Each submersible centrifugal pump has its own code, which reflects the diameter of the column, flow and pressure. For example, the ETSN6-500-750 pump is an electric centrifugal pump for casing strings with a diameter of 6, with an optimal supply of 500 m 3 / day at a head of 750 m.

The principle of operation of the pump can be represented as follows: the liquid sucked through the intake filter enters the blades of a rotating impeller, under the influence of which it acquires speed and pressure. To convert kinetic energy into pressure energy, the fluid leaving the impeller is directed to fixed channels of variable cross section of the working apparatus connected to the pump housing, then the liquid, leaving the working apparatus, enters the impeller of the next stage and the cycle repeats. Centrifugal pumps are designed for high shaft speeds.

All types of ESP have a passport operating characteristic(Figure 1.3) in the form of dependence curves (head, flow), (efficiency, flow), (power consumption, flow). The dependence of the pressure on the flow is the main characteristic of the pump.

Figure 1.3 - Typical characteristics of a submersible centrifugal pump

• 2) Submersible electric motor (SEM) - a motor of a special design and is an asynchronous two-pole AC motor with a squirrel-cage rotor. The motor is filled with low-viscosity oil, which performs the function of lubricating the rotor bearings and removing heat to the walls of the motor housing, which is washed by the flow of well products. The upper end of the motor shaft is suspended on the sliding heel. Sectional motor rotor; sections are assembled on the motor shaft, made of transformer iron plates and have grooves into which aluminum rods are inserted, shorted on both sides of the section with conductive rings. Between the sections, the shaft rests on bearings. Along the entire length, the motor shaft has a hole for oil circulation inside the motor, which is also carried out through the stator groove. There is an oil filter at the bottom of the engine. The stator sections are separated by non-magnetic packages, in which thrust radial bearings are located. The lower end of the shaft is also fixed in the bearing. The length and diameter of the engine determine its power. The rotation speed of the SEM shaft depends on the frequency of the current; at 50 Hz AC, the synchronous speed is 3000 rpm. Submersible motors are marked with power (in kW) and outer diameter of the body (mm), for example, PED 65-117 - a submersible motor with a power of 65 kW and an outer diameter of 117 mm. The required power of the electric motor depends on the flow and pressure of the submersible centrifugal pump and can reach hundreds of kW.
• 3) The hydraulic protection unit is located between the pump and the motor and is designed to protect the electric motor from ingress of pumped products and lubrication of the pump angular contact bearing (if necessary). The main volume of the hydraulic protection unit, formed by an elastic bag, is filled with liquid oil. Through the check valve, the outer surface of the bag perceives the pressure of the well production at the depth of the descent of the submersible unit. Thus, inside an elastic bag filled with liquid oil, the pressure is equal to the immersion pressure. To create excess pressure inside this bag, there is an impeller on the tread shaft. Liquid oil through a system of channels under excess pressure enters the internal cavity of the electric motor, which prevents the penetration of well products into the electric motor.
• 4) The compensator is designed to compensate for the volume of oil inside the engine when the temperature regime of the electric motor changes (heating and cooling) and is an elastic bag filled with liquid oil and located in the housing. The body of the compensator has holes communicating the outer surface of the bag with the well. The inner cavity of the bag is connected with the electric motor, and the outer one - with the well. When the oil is cooled, its volume decreases, and the well fluid through the holes in the compensator body enters the gap between the outer surface of the bag and the inner wall of the compensator body, thereby creating conditions for the complete filling of the internal cavity of the submersible motor with oil. When the oil in the electric motor is heated, its volume increases, and the oil flows into the internal cavity of the compensator bag; in this case, the downhole fluid from the gap between the outer surface of the bag and the inner surface of the body is squeezed out through the holes into the well. All housings of the elements of the submersible unit are interconnected by flanges with studs. The shafts of the submersible pump, the hydraulic protection unit and the submersible electric motor are interconnected by splined couplings. Thus, the ESP submersible unit is a complex of complex electrical, mechanical and hydraulic devices of high reliability, which requires highly qualified personnel.
• 5) The check valve is located in the pump head and is designed to prevent liquid from draining through the pump from the tubing string when the submersible unit stops. Stops of the submersible unit occur for many reasons: a power outage in case of an accident on the power line; shutdown due to operation of the SEM protection; shutdown during periodic operation, etc. When the submersible unit is stopped (power-off), the liquid column from the tubing begins to flow through the pump into the well, spinning the pump shaft (and hence the shaft of the submersible motor) in the opposite direction. If the power supply is restored during this period, the motor starts to rotate in the forward direction, overcoming the enormous force. The starting current of the SEM at this moment may exceed the permissible limits, and if the protection does not work, the electric motor fails. To prevent this phenomenon and reduce downtime of the well, the submersible pump is equipped with a check valve. On the other hand, the presence of a check valve when lifting the submersible unit does not allow liquid to drain from the tubing string. The installation is lifted when the tubing string is filled with well products, which spill out at the wellhead, creating extremely difficult working conditions for the underground repair team and violating all conditions for ensuring life safety, fire and environmental protection, which is unacceptable. Therefore, the submersible pump is equipped with a drain valve. well spatial equipment
• 6) The drain valve is placed in a special coupling connecting the tubing pipes, and is usually a bronze tube, one end of which is sealed, and the other, open end, is threaded into the coupling from the inside. The drain valve is located horizontally with respect to the vertical tubing string. If it is necessary to lift the installation from the well, a small load is dropped into the tubing string, which breaks off the bronze tube of the drain valve, and the liquid from the tubing is drained into the annulus during lifting.
• 6) The electrical cable is designed to supply voltage to the terminals of the submersible motor. The cable is three-core, with rubber or polyethylene insulation and is covered with metal armor on top. The surface armoring of the cable is carried out by a galvanized steel profiled tape, which prevents current-carrying conductors from mechanical damage during the descent and ascent of the installation. Round and flat cables are available. The flat cable has smaller radial dimensions. The cables are encrypted as follows: KRBK, KRBP - cable with rubber insulation, armored, round; cable with rubber insulation, armored, flat. Copper conductors, with different cross-sections. The cable is attached to the tubing string in two places: above the sleeve and below the sleeve. At present, cables with polyethylene insulation are predominantly used.
• 7) The autotransformer is designed to increase the voltage applied to the submersible motor terminals. The mains voltage is 380 V, and the operating voltage of the electric motors, depending on the power, varies from 400 V to 2000 V. With the help of an autotransformer, the voltage of the 380 V field network is increased to the operating voltage of each specific submersible electric motor, taking into account voltage losses in the supply cable. The size of the autotransformer corresponds to the power of the submersible motor used.
• 8) The control station is designed to control the operation and protect the ESP and can operate in manual and automatic modes. The station is equipped with the necessary control and measuring systems, automatic devices, all kinds of relays (maximum, minimum, intermediate, time relays, etc.). In the event of emergency situations, the corresponding protection systems are triggered, and the unit is turned off. The control station is made in a metal box, can be installed outdoors, but is often placed in a special booth.

Purpose and technical data of the ESP.

Installations of submersible centrifugal pumps are designed for pumping out of oil wells, including inclined reservoir fluid containing oil, water and gas, and mechanical impurities. Depending on the number of different components contained in the pumped liquid, the pumps of the installations are of standard and increased corrosion and wear resistance. During the operation of the ESP, where the concentration of mechanical impurities in the pumped liquid exceeds the allowable 0.1 gram / liter, clogging of the pumps occurs, intensive wear of the working units. As a result, vibration increases, water gets into the SEM through the mechanical seals, the engine overheats, which leads to the failure of the ESP.

Conventional designation of installations:

ESP K 5-180-1200, U 2 ESP I 6-350-1100,

Where U - installation, 2 - second modification, E - driven by a submersible electric motor, C - centrifugal, N - pump, K - increased corrosion resistance, I - increased wear resistance, M - modular design, 6 - groups of pumps, 180, 350 - flow m/day, 1200, 1100 – head, m.w.st.

Depending on the diameter of the production string, the maximum transverse dimension of the submersible unit, ESPs of various groups are used - 5.5, and 6. Installation of group 5 with a transverse diameter of at least 121.7 mm. Installations of group 5 a with a transverse dimension of 124 mm - in wells with an internal diameter of at least 148.3 mm. Pumps are also divided into three conditional groups - 5.5 a, 6. The diameters of the cases of group 5 are 92 mm, groups 5 a are 103 mm, groups 6 are 114 mm. Specifications pumps of the ETsNM and ETsNMK types are given in Appendix 1.

Composition and completeness of the ESP

The ESP unit consists of a submersible pump unit (an electric motor with hydraulic protection and a pump), a cable line (a round flat cable with a cable entry sleeve), a tubing string, wellhead equipment and ground electrical equipment: a transformer and a control station (complete device) (see Figure 1.1 .). The transformer substation converts the voltage of the field network of a suboptimal value at the terminals of the electric motor, taking into account the voltage losses in the cable. The control station provides control of the operation of pumping units and its protection under optimal conditions.

A submersible pumping unit, consisting of a pump and an electric motor with hydraulic protection and a compensator, is lowered into the well along the tubing. The cable line provides power supply to the electric motor. The cable is attached to the tubing with metal wheels. The cable is flat along the length of the pump and protector, attached to them by 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 (see Figure 1.2.)

The wellhead equipment provides suspension on the casing flange of the tubing string with an electric pump and cable, sealing pipes and cables, as well as draining the produced fluid into the outlet pipeline.

A submersible, centrifugal, sectional, multistage pump does not differ in principle from conventional centrifugal pumps.

Its difference is that it is sectional, multi-stage, with a small diameter of working steps - impellers and guide vanes. Submersible pumps produced for the oil industry contain from 1300 to 415 stages.

The sections of the pump connected by flange connections are a metal casing. Made from steel pipe 5500 mm long. The length of the pump is determined by the number of operating stages, the number of which, in turn, is determined by the main parameters of the pump. - delivery and pressure. The flow and head of the stages depend on the cross section and design of the flow path (blades), as well as on the rotational speed. In the casing of the pump sections, a package of stages is inserted, which is an assembly of impellers and guide vanes on the shaft.

The impellers are mounted on a shaft on a feather key in a running fit and can move in the axial direction. The guide vanes are secured against rotation in the nipple housing located at the top of the pump. From below, the pump base is screwed into the housing with inlet holes and a filter through which the liquid from the well enters the first stage of the pump.

The upper end of the pump shaft rotates in the stuffing box bearings and ends with a special heel that takes the load on the shaft and its weight through the spring ring. Radial forces in the pump are perceived by plain bearings installed at the base of the nipple and on the pump shaft.

At the top of the pump is a fishing head, in which a check valve is installed and to which the tubing is attached.

Submersible electric motor, three-phase, asynchronous, oil-filled with a squirrel-cage rotor in the usual version and corrosion-resistant versions of the PEDU (TU 16-652-029-86). Climatic modification - B, placement category - 5 according to GOST 15150 - 69. At the base of the electric motor there is a valve for pumping oil and draining it, as well as a filter for cleaning oil from mechanical impurities.

The hydroprotection of the SEM consists of a protector and a compensator. It is designed to protect the internal cavity of the electric motor from formation fluid ingress, as well as to compensate for temperature changes in oil volumes and its consumption. (See figure 1.3.)

Two-chamber protector, with a rubber diaphragm and mechanical shaft seals, compensator with a rubber diaphragm.

Three-core cable with polyethylene insulation, armored. 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 a layer of insulation and sheath, pads of rubberized fabric and armor. Three insulated conductors 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 gland K 38, K 46 round type. In a metal case, the couplings are hermetically sealed with a rubber seal, lugs are attached to the conductive wires.

The design of UETsNK, UETsNM units with a pump having a shaft and stages made of corrosion-resistant materials, and UETsNI with a pump having plastic impellers and rubber-metal bearings is similar to the design of UETsN units.

With a large gas factor, pumping modules are used - gas separators designed to reduce the volume content of free gas at the pump intake. Gas separators correspond to product group 5, type 1 (restorable) according to RD 50-650-87, climatic design - B, placement category - 5 according to GOST 15150-69.

Modules can be supplied in two versions:

Gas separators: 1 MNG 5, 1 MNG5a, 1MNG6 - standard version;

Gas separators 1 MNGK5, MNG5a - increased corrosion resistance.

Pump modules are installed between the input module and the module-section of the submersible pump.

The submersible pump, electric motor, and hydraulic protection are interconnected by flanges and studs. The shafts of the pump, motor and protector have splines at the ends and are connected by spline couplings.

Components for hoists and equipment for ESP units are given in Appendix 2.

Technical characteristics of SEM

The submersible centrifugal pumps are driven by a special oil-filled submersible asynchronous electric motor of three-phase alternating current with a vertical squirrel-cage rotor type PED. Electric motors have housing diameters of 103, 117, 123, 130, 138 mm. Since the diameter of the electric motor is limited, at high powers the motor has a large length, and in some cases it is sectional. Since the electric motor operates immersed in liquid and often under high hydrostatic pressure, the main condition for reliable operation is its tightness (see figure 1.3).

The SEM is filled with a special low-viscosity, high dielectric strength oil, which serves both for cooling and for lubricating parts.

The submersible electric motor consists of a stator, a rotor, a head, a base. The stator housing is made of a steel pipe, at the ends of which there is a thread for connecting the motor head and base. The stator magnetic circuit is assembled from active and non-magnetic laminated sheets with grooves in which the winding is located. The stator winding can be single-layer, lingering, reel or double-layer, rod, loop. The winding phases are connected.

The active part of the magnetic circuit, together with the winding, creates a rotating magnetic field in the electric motors, and the non-magnetic part serves as supports for the intermediate rotor bearings. To the ends of the stator winding, lead-out ends are soldered, made of stranded copper wire with insulation, having high electrical and mechanical strength. Solder sleeves to the ends, which include cable lugs. The output ends of the winding are connected to the cable through a special plug-in block (sleeve) of the cable gland. The current lead of the motor can also be of the knife type. The motor rotor is squirrel-cage, multi-section. It consists of a shaft, cores (rotor packs), radial bearings (sliding bearings). The rotor shaft is made of hollow calibrated steel, the cores are made of sheet electrical steel. The cores are mounted on the shaft, alternating with radial bearings, and are connected to the shaft with keys. Tighten the set of cores on the shaft in the axial direction with nuts or a turbine. The turbine serves to force oil circulation to equalize the temperature of the motor along the length of the stator. To ensure oil circulation, there are longitudinal grooves on the immersed surface of the magnetic circuit. The oil circulates through these slots, the filter at the bottom of the engine where it is cleaned, and through a hole in the shaft. The heel and bearing are located in the engine head. The sub at the bottom of the engine is used to accommodate the filter, bypass valve, and valve for pumping oil into the engine. The sectional version electric motor consists of upper and lower sections. Each section has the same basic nodes. The technical characteristics of the SEM are given in Appendix 3.

Basic technical data of the cable

Electricity is supplied to the electric motor of the submersible pump installation through a cable line consisting of a supply cable and a cable entry sleeve for articulation with the electric motor.

Depending on the purpose, the cable line may include:

Cable brands KPBK or KPPBPS - as the main cable.

Cable brand KPBP (flat)

The cable entry sleeve is round or flat.

The KPBK cable consists of copper single-wire or multi-wire cores, insulated in two layers with high-strength polyethylene and twisted together, as well as cushions and armor.

Cables of KPBP and KPPBPS brands in a common hose sheath consist of copper single-wire and multi-wire conductors insulated with high-density polyethylene and laid in one plane, as well as from a common hose sheath, cushion and armor.

Cables of the brand KPPBPS with separately hosed conductors consist of copper single- and multi-wire conductors insulated in two layers of polyethylene high pressure and laid in the same plane.

Cable brand KPBK has:

Operating voltage V - 3300

Cable brand KPBP has:

Operating voltage, V - 2500

Permissible reservoir fluid pressure, MPa - 19.6

Permissible GOR, m/t – 180

The cable of KPBK and KPBP grades has admissible ambient temperatures from 60 to 45 C for air, 90 C for reservoir fluid.

Cable line temperatures are given in Appendix 4.

1.2. Brief review of domestic schemes and installations.

Installations of submersible centrifugal pumps are designed for pumping oil wells, including inclined ones, reservoir fluid containing oil and gas, and mechanical impurities.

The units are produced in two types - modular and non-modular; three versions: conventional, corrosion-resistant and increased wear resistance. The pumped medium of domestic pumps must have the following indicators:

· reservoir savagery - a mixture of oil, associated water and petroleum gas;

· maximum kinematic viscosity of formation fluid 1 mm/s;

· pH value of associated water pH 6.0-8.3;

· the maximum content of the received water of 99%;

free gas at the intake up to 25%, for units with separator modules up to 55%;

· the maximum temperature of the extracted product is up to 90C.

Depending on the transverse dimensions of the submersible centrifugal electric pumps, electric motors and cable lines used in the set of installations, the installations are conditionally divided into 2 groups 5 and 5 a. With casing string diameters of 121.7 mm; 130 mm; 144.3 mm respectively.

The UEC installation consists of a submersible pump unit, a cable assembly, ground electrical equipment - a transformer co-current substation. The pumping unit consists of a submersible centrifugal pump and a motor with hydraulic protection; it is lowered into the well on the tubing string. The pump is submersible, three-phase, asynchronous, oil-filled with a rotor.

Hydroprotection consists of a protector and a compensator. Three-core cable with polyethylene insulation, armored.

The submersible pump, electric motor and hydraulic protection are interconnected by flanges and studs. The shafts of the pump, motor and protector have splines at the ends and are connected by spline couplings.

1.2.2. Submersible centrifugal pump.

A submersible centrifugal pump does not differ in principle from conventional centrifugal pumps used for pumping liquids. The difference is that it is multi-sectional with a small diameter of working steps - impellers and guide vanes. Impellers and guide vanes of conventional pumps are made of modified gray cast iron, corrosion-resistant pumps are made of niresist cast iron, and wear-resistant wheels are made of their polyamide resins.

The pump consists of sections, the number of which depends on the main parameters of the pump - pressure, but not more than four. Section length up to 5500 meters. For modular pumps, it consists of an input module, a module - a section. Module - head, check and drain valves. Connection between modules and the input module with the motor - flange connection (except for the input module, motor or separator) is sealed with rubber cuffs. Shafts of modules-sections are connected to each other, module-sections are connected to the shaft of the input module, the shaft of the input module is connected to the shaft of the hydraulic protection of the engine by splined couplings. Shafts of modules-sections of all groups of pumps with the same length of casings are unified in length.

The module-section consists of a body, a shaft, a package of steps (impellers and guide vanes), upper and lower bearings, an upper axial bearing, a head, a base, two ribs and rubber rings. The ribs are designed to protect the flat cable with a sleeve from mechanical damage.

The input module consists of a base with holes for formation fluid passage, bearing bushings and mesh, a shaft with protective bushings and a splined coupling designed to connect the module shaft with the hydraulic protection shaft.

The head module consists of a body, on one side of which there is an internal conical thread for connecting a check valve, on the other side - a flange for connecting to the section module, two ribs and a rubber ring.

There is a fishing head at the top of the pump.

The domestic industry produces pumps with a flow rate (m / day):

Modular - 50,80,125,200.160,250,400,500,320,800,1000.1250.

Non-modular - 40.80,130.160,100,200,250,360,350,500,700,1000.

The following heads (m) - 700, 800, 900, 1000, 1400, 1700, 1800, 950, 1250, 1050, 1600, 1100, 750, 1150, 1450, 1750, 1800, 1700, 1550, 1300.

1.2.3. Submersible motors

Submersible electric motors consist of an electric motor and hydraulic protection.

Three-phase, asynchronous, squirrel-cage, two-pole, submersible, unified series motors. SEM in normal and corrosive versions, climatic version B, placement category 5, operate on AC mains with a frequency of 50 Hz and are used as a drive for submersible centrifugal pumps.

The engines are designed to operate in formation fluid (a mixture of oil and produced water in any proportions) with temperatures up to 110 C containing:

· mechanical impurities not more than 0.5 g/l;

free gas no more than 50%;

· hydrogen sulfide for normal, not more than 0.01 g/l, corrosion-resistant up to 1.25 g/l;

Hydroprotective pressure in the area of ​​engine operation is not more than 20 MPa. Electric motors are filled with oil with a breakdown voltage of at least 30 kV. The maximum long-term allowable temperature of the stator winding of the electric motor (for a motor with a housing diameter of 103 mm) is 170 C, for other electric motors 160 C.

The engine consists of one or more electric motors (upper, middle and lower, power from 63 to 630 kW) and a protector. The electric motor consists of a stator, a rotor, a head with a current lead, and a housing.

1.2.4. Hydroprotection of the electric motor.

Hydraulic protection is designed to prevent the penetration of reservoir fluid into the internal cavity of the electric motor, to compensate for the volume of oil in the internal cavity from the temperature of the electric motor and to transfer torque from the electric motor shaft to the pump shaft. There are several options for waterproofing: P, PD, G.

Hydroprotection is produced in standard and corrosion-resistant versions. The main type of hydraulic protection for the SEM assembly is an open-type hydraulic protection. Open-type hydraulic protection requires the use of a special barrier fluid with a density of up to 21 g/cm, which has physical and chemical properties with formation fluid and oil.

The hydroprotection consists of two chambers connected by a tube. The change in the volumes of the liquid dielectric in the engine is compensated by the overflow of the barrier liquid from one chamber to another. In closed-type hydroprotection, rubber diaphragms are used. Their elasticity compensates for the change in oil volume.

24. The condition of well flowing, determination of energy and specific gas consumption during the operation of a gas-liquid lift.

Well flowing conditions.

Well flowing occurs if the pressure drop between the formation and bottom hole is sufficient to overcome the back pressure of the liquid column and friction pressure losses, that is, the flowing occurs under the action of the hydrostatic pressure of the liquid or the energy of the expanding gas. Most wells flow due to gas energy and hydrostatic head at the same time.

The gas in the oil has a lifting force, which manifests itself in the form of pressure on the oil. The more gas dissolved in the oil, the less dense the mixture will be and the higher the liquid level will rise. Having reached the mouth, the liquid overflows, and the well begins to flow. The general prerequisite for the operation of any flowing well will be the following basic equality:

Pc \u003d Rg + Rtr + Ru; where

Рс - bottomhole pressure, РР, Рtr, Ру - hydrostatic pressure of the liquid column in the well, calculated along the vertical, pressure losses due to friction in the tubing and backpressure at the wellhead, respectively.

There are two types of well flowing:

· Gushing of a liquid that does not contain gas bubbles - artesian gushing.

· Spouting a liquid containing bubbles of gas that facilitates spouting is the most common type of spouting.

Ground equipment includes a control station, an autotransformer, a drum with an electric cable and wellhead fittings.

Electrical equipment, depending on the current supply scheme, includes either a complete transformer substation for submersible pumps (KTPPN), or a transformer substation (TP), a control station and a transformer.

Electricity from the transformer (or from KTPPN) to the submersible motor is supplied through a cable line, which consists of a ground supply cable and a main cable with an extension. The connection of the ground cable with 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 electrical equipment is protected from flooding during the flood period and cleared of snow in the winter, and must have entrances that allow you to freely mount and dismantle the equipment. Responsibility for the working condition of the sites and entrances to them rests with the CDNG.

control station

With the help of the control station, manual control of the engine is carried out, automatic shutdown unit when the liquid supply is interrupted, zero protection, overload protection and shutdown of the unit in case of short circuits. During the operation of the unit, the centrifugal current pump sucks in liquid through a filter installed at the pump intake and pumps it through the pump pipes to the surface. Depending on the pressure, i.e. liquid lifting heights, pumps with a different number of stages are used. A check and drain valve is installed above the pump. The check valve is used to maintain in the tubing, which makes it easier to start the engine and control its operation after starting. During operation, the check valve is in the open position by pressure from below. A drain valve is installed above the return valve, and is used to drain fluid from the tubing as it rises to the surface.

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 to work outdoors. On the high side of the windings of the transformers, fifty taps are made to supply the optimal voltage to the electric motor, depending on the length of the cable, the load on the electric motor and the mains voltage.

Switching taps is carried out with the transformer completely disconnected.

The transformer consists of a magnetic circuit, 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 40kW.

On transformers with a power of 100 - 200 kW, a thermosiphon filter is installed to clean transformer oil from aging products.

Mounted on the tank lid:

HV winding tap changer drive (one or two);

Mercury thermometer for measuring the temperature of the upper layers of oil;

Removable inputs of HV and LV, allowing the replacement of insulators without lifting the part to be removed;

Expander with oil gauge and air dryer;

Metal box to protect the inputs from dust and moisture.

An air dryer with an oil seal is designed to remove moisture and clean industrial air pollution from the air entering the transformer during temperature fluctuations in the oil level.

Wellhead fittings

Wellhead fittings are designed to divert products from the well to the flow line and seal the annulus.

The wellhead fittings of the well prepared for the launch of the ESP are equipped with pressure gauges, a check valve on the line connecting the annular space with the discharge, a choke chamber (if technologically feasible) and a branch pipe for research. Responsibility for the implementation of this paragraph lies with the CDNG.

The wellhead fittings, in addition to the functions performed with all methods of production, must ensure the tightness of the reciprocating polished rod moving in it. The latter is a mechanical connection between the rod string and the head of the balancer SK.

Wellhead fittings, manifolds and flow lines, which have a complex configuration, complicate the hydrodynamics of the flow. Downhole equipment located on the surface is relatively accessible and relatively easy to clean from deposits, mainly by thermal methods.

Wellhead fittings of wells through which water is pumped into the formation are subjected to hydraulic testing in the manner established for X-mas tree fittings.

Underground ESP equipment

Underground equipment includes tubing, pumping unit and eclectic armored cable.

Centrifugal pumps for pumping liquid from a well are not fundamentally different from conventional centrifugal pumps used to pump liquids on the surface of the earth. However, small radial dimensions, due to the diameter of the casing strings into which centrifugal pumps are lowered, practically unlimited axial dimensions, the need to overcome high heads and the operation of the pump in a submerged state led to the creation of centrifugal pumping units of a specific design. Outwardly, they are no different from a pipe, but the inner cavity of such a pipe contains a large number of complex parts that require perfect manufacturing technology.

Submersible centrifugal electric pumps (PTSEN) are multistage centrifugal pumps with up to 120 stages in one unit, driven by a submersible electric motor of a special design (SEM). The electric motor is powered from the surface by electricity supplied via a cable from a step-up autotransformer or transformer through a control station, in which all control and measuring equipment and automation are concentrated. The PTSEN is lowered into the well under the calculated dynamic level, usually by 150 - 300 m. The fluid is supplied through the tubing, to the outer side of which an electric cable is attached with special belts. In the pump unit between the pump itself and the electric motor there is an intermediate link called a protector or hydraulic protection. The PTSEN installation (Figure 3) includes an oil-filled electric motor SEM 1; hydraulic protection link or protector 2; intake grid of the pump for fluid intake 3; multistage centrifugal pump ПЦЭН 4; tubing 5; armored three-core electric cable 6; belts for attaching the cable to the tubing 7; wellhead fittings 8; a drum for winding a cable during tripping and storing a certain supply of cable 9; transformer or autotransformer 10; control station with automation 11 and compensator 12.

The pump, protector and electric motor are separate units connected by bolted studs. The ends of the shafts have splined connections, which are joined when assembling the entire installation. If it is necessary to lift liquid from great depths, the PTSEN sections are connected to each other so that the total number of stages reaches 400. The liquid sucked in by the pump sequentially passes through all stages and leaves the pump with a pressure equal to the external hydraulic resistance.

Figure 3 - General scheme of well equipment with a submersible centrifugal pump installation

UTSEN are distinguished by low metal consumption, a wide range of performance characteristics, both in terms of pressure and flow, a sufficiently high efficiency, the possibility of pumping large amounts of liquid and a long overhaul period. It should be recalled that the average liquid supply for Russia of one UPTsEN is 114.7 t/day, and USSSN - 14.1 t/day.

All pumps are divided into two main groups; conventional and wear-resistant design. The vast majority of the operating stock of pumps (about 95%) is of conventional design.

Wear-resistant pumps are designed to work in wells, in the production of which there is a small amount of sand and other mechanical impurities (up to 1% by weight). According to the transverse dimensions, all pumps are divided into 3 conditional groups: 5; 5A and 6, which is the nominal casing diameter, in inches, into which the pump can be run.

Group 5 has an outer case diameter of 92 mm, group 5A - 103 mm and group b - 114 mm. The speed of the pump shaft corresponds to the frequency of the alternating current in the mains. In Russia, this frequency is 50 Hz, which gives a synchronous speed (for a two-pole machine) of 3000 min-1. The PTSEN cipher contains their main nominal parameters, such as flow and pressure when operating in the optimal mode. For example, ESP5-40-950 means a group 5 centrifugal electric pump with a flow of 40 m3/day (by water) and a head of 950 m. ESP5A-360-600 means a group 5A pump with a flow of 360 m3/day and a head of 600 m.

Figure 4 - Typical characteristics of a submersible centrifugal pump

In the code of wear-resistant pumps, there is the letter I, which means wear resistance. In them, impellers are made not from metal, but from polyamide resin (P-68). In the pump housing, approximately every 20 stages, intermediate rubber-metal shaft centering bearings are installed, as a result of which the wear-resistant pump has fewer stages and, accordingly, pressure.

The end bearings of the impellers are not cast iron, but in the form of pressed rings made of hardened steel 40X. Instead of textolite support washers between the impellers and guide vanes, washers made of oil-resistant rubber are used.

All types of pumps have a passport performance characteristic in the form of dependency curves H (Q) (pressure, flow), h (Q) (efficiency, flow), N (Q) (power consumption, flow). Usually these dependencies are given in the range of operating flow rates or in a slightly larger interval (Fig. 11.2).

Any centrifugal pump, including the PTSEN, can operate with a closed outlet valve (point A: Q = 0; H = Hmax) and without counterpressure at the outlet (point B: Q = Qmax; H = 0). Because the useful work pump is proportional to the product of the supply to the head, then for these two extreme modes of operation of the pump, the useful work will be equal to zero, and, consequently, the efficiency will be equal to zero. At a certain ratio (Q and H), due to the minimum internal losses of the pump, the efficiency reaches a maximum value of approximately 0.5 - 0.6. Usually pumps with low flow and small diameter impellers, as well as with a large number stages have a reduced efficiency. The flow and pressure corresponding to the maximum efficiency are called the optimal mode of operation of the pump. The dependence z(Q) near its maximum decreases smoothly, therefore, the operation of the PTSEN is quite acceptable in modes that differ from the optimal the limits of these deviations will depend on the specific characteristics of the PTSEN and should correspond to a reasonable decrease in the efficiency of the pump (by 3 - 5%). This causes a whole range of possible modes of operation of the PTSEN, which is called the recommended (see fig. 11.2, hatching).

The selection of a pump for wells essentially boils down to choosing such a standard size of the PTSEN that, when lowered into the well, it would operate under the conditions of the optimal or recommended mode when pumping a given well flow rate from a given depth.

The pumps currently produced are designed for nominal flow rates from 40 (ETsN5-40-950) to 500 m3/day (ETsN6-500-750) and heads 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 reservoirs. These pumps have flows up to 3000 m3/day and heads up to 1200 m.

The head that a pump can overcome is directly proportional to the number of stages. Developed by one stage at the optimum operating mode, it depends, in particular, on the dimensions of the impeller, which in turn depend on the radial dimensions of the pump. With an outer diameter of the pump casing of 92 mm, the average head 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 to 6.84 m.

The pumping unit consists of a pump (Figure 4, a), a hydraulic protection unit (Figure 4, 6), a SEM submersible motor (Figure 4, c), a compensator (Figure 4, d) attached to the lower part of the SEM.

The pump consists of the following parts: a head 1 with a ball check valve to prevent fluid from draining from the tubing during shutdowns; the upper bearing foot of the slide 2, which partially perceives the axial load due to the pressure difference at the inlet and outlet of the pump; upper plain bearing 3 centering the upper end of the shaft; pump housing 4; guide vanes 5, which rest on each other and are kept from rotation by a common coupler in the housing 4; impellers 6; pump shaft 7, which has a longitudinal key on which impellers are mounted with a sliding fit. The shaft also passes through the guide apparatus of each stage and is centered in it by the impeller bushing, as in a bearing; lower plain bearing 8; base 9, closed with a receiving grid and having round inclined holes in the upper part for supplying liquid to the lower impeller; end plain bearing 10. In pumps of early designs that are still in operation, the device of the lower part is different. Along the entire length of the base 9 is placed a gland of lead-graphite rings, separating the receiving part of the pump and the internal cavities of the engine and hydraulic protection. A three-row angular contact ball bearing is mounted below the stuffing box, lubricated with thick oil, which is under some pressure (0.01 - 0.2 MPa) in relation to the external one.

Figure 4 - The device of the submersible centrifugal unit

a - centrifugal pump; b - hydraulic protection unit; c - submersible electric motor; g - compensator

In modern ESP designs, there is no excess pressure in the hydroprotection unit, therefore, there is less leakage of liquid transformer oil, with which the SEM is filled, and the need for a lead-graphite gland has disappeared.

The cavities of the engine and the receiving part are separated by a simple mechanical seal, the pressures on both sides of which are the same. The length of the pump housing usually does not exceed 5.5 m. When the required number of stages (in pumps that develop high pressures) cannot be placed in one housing, they are placed in two or three separate housings that make up independent sections of one pump, which are docked together when lowering the pump into the well

The hydraulic protection unit is an independent unit attached to the PTSEN by a bolted connection (in Figure 4, the unit, like the PTSEN itself, is shown with transport plugs sealing the ends of the units)

The upper end of shaft 1 is connected by a splined coupling to the lower end of the pump shaft. A light mechanical seal 2 separates the upper cavity, which may contain well fluid, from the cavity below the seal, which is filled with transformer oil, which, like the well fluid, is under pressure equal to the pressure at the immersion depth of the pump. Below the mechanical seal 2 there is a sliding friction bearing, and even lower - node 3 - a bearing foot that perceives the axial force of the pump shaft. The sliding foot 3 operates in liquid transformer oil.

Below is the second mechanical seal 4 for more reliable sealing of the engine. It is not structurally different from the first. Under it is a rubber bag 5 in the body 6. The bag hermetically separates two cavities: the inner cavity of the bag filled with transformer oil, and the cavity between the body 6 and the bag itself, into which the external well fluid has access through the check valve 7.

The downhole fluid through the valve 7 penetrates into the cavity of the housing 6 and compresses the rubber bag with oil to a pressure equal to the external one. Liquid oil penetrates through the gaps along the shaft to the mechanical seals and down to the PED.

Two designs of hydraulic protection devices have been developed. The hydroprotection of the main engine differs from the described hydroprotection of the G by the presence of a small turbine on the shaft, which creates an increased pressure of liquid oil in the internal cavity of the rubber bag 5.

The outer cavity between the housing 6 and the bag 5 is filled with thick oil, which feeds the ball angular contact bearing PTSEN of the previous design. Thus, the hydraulic protection unit of the main engine of an improved design is suitable for use in conjunction with the PTSEN of the previous types that are widely used in the fields. Previously, hydraulic protection was used, the so-called piston-type protector, in which excess pressure on the oil was created by a spring-loaded piston. New designs of the main engine and the main engine proved to be more reliable and durable. Temperature changes in the volume of oil during its heating or cooling are compensated by attaching a rubber bag - compensator to the bottom of the PED.

To drive the PTSEN, special vertical asynchronous oil-filled bipolar electric motors (SEMs) are used. Pump motors are divided into 3 groups: 5; 5A and 6.

Since, unlike the pump, the electric cable does not pass along the motor housing, the diametrical dimensions of the SEMs of these groups are somewhat larger than those of the pumps, namely: group 5 has a maximum diameter of 103 mm, group 5A - 117 mm and group 6 - 123 mm.

The marking of the SEM includes the rated power (kW) and diameter; for example, PED65-117 means: a submersible electric motor with a power of 65 kW with a housing diameter of 117 mm, i.e. included in group 5A.

Small allowable diameters and high power (up to 125 kW) make it necessary to make engines of great length - up to 8 m, and sometimes more. The upper part of the PED is connected to the lower part of the hydraulic protection assembly using bolted studs. Shafts are joined by spline couplings.

The upper end of the PED shaft is suspended on the sliding heel 1, which operates in oil. Below is the cable entry assembly 2. This assembly is usually a male cable connector. This is one of the most vulnerable places in the pump, due to the violation of the insulation of which the installations fail and require lifting; 3 - lead wires of the stator winding; 4 - upper radial sliding friction bearing; 5 - section of the end ends of the stator winding; 6 - stator section, assembled from stamped transformer iron plates with grooves for pulling stator wires. The stator sections are separated from each other by non-magnetic packages, in which the radial bearings 7 of the motor shaft 8 are strengthened. The lower end of the shaft 8 is centered by the lower radial sliding friction bearing 9. The SEM rotor also consists of sections assembled on the motor shaft from stamped plates of transformer iron. Aluminum rods are inserted into the slots of the squirrel-wheel type rotor, shorted by conductive rings, on both sides of the section. Between the sections, the motor shaft is centered in bearings 7. A hole with a diameter of 6–8 mm passes through the entire length of the motor shaft for oil to pass from the lower cavity to the upper one. Along the entire stator there is also a groove through which oil can circulate. The rotor rotates in liquid transformer oil with high insulating properties. In the lower part of the PED there is a mesh oil filter 10. The head 1 of the compensator (see Fig. 11.3, d) is attached to the lower end of the PED; bypass valve 2 serves to fill the system with oil. The protective casing 4 in the lower part has holes for transferring the external fluid pressure to the elastic element 3. When the oil cools, its volume decreases and the well fluid through the holes enters the space between the bag 3 and the casing 4. When heated, the bag expands, and the fluid through the same holes comes out of the casing.

PEDs used for the operation of oil wells usually have capacities from 10 to 125 kW.

To maintain reservoir pressure, special submersible pumping units are used, equipped with 500 kW PEDs. The supply voltage in the SEM ranges from 350 to 2000 V. At high voltages, it is possible to proportionally reduce the current when transmitting the same power, and this makes it possible to reduce the cross section of the cable conductors, and, consequently, the transverse dimensions of the installation. This is especially important for high power motors. SEM rotor slip nominal - from 4 to 8.5%, efficiency - from 73 to 84%, permissible ambient temperatures - up to 100 °C.

A lot of heat is generated during the operation of the PED, so cooling is required for the normal operation of the engine. Such cooling is created due to the continuous flow of formation fluid through the annular gap between the motor housing and the casing string. For this reason, wax deposits in the tubing during pump operation are always significantly less than during other methods of operation.

Under production conditions, there is a temporary blackout of power lines due to a thunderstorm, wire breakage, due to icing, etc. This causes a stop of the UTSEN. In this case, under the influence of the liquid column flowing from the tubing through the pump, the pump shaft and the stator begin to rotate in the opposite direction. If at this moment the power supply is restored, the SEM will begin to rotate in the forward direction, overcoming the force of inertia of the liquid column and the rotating masses.

Starting currents in this case may exceed the permissible limits, and the installation will fail. To prevent this from happening, a ball check valve is installed in the discharge part of the PTSEN, which prevents the liquid from draining from the tubing.

The check valve is usually located in the pump head. The presence of a check valve complicates the rise of the tubing when repair work ah, since in this case the pipes are lifted and unscrewed with liquid. In addition, it is dangerous in terms of fire. To prevent such phenomena, a drain valve is made in a special coupling above the check valve. In principle, the drain valve is a coupling, in the side wall of which a short bronze tube is inserted horizontally, sealed from the inner end. Before lifting, a short metal dart is thrown into the tubing. The blow of the dart breaks off the bronze tube, as a result of which the side hole in the sleeve opens and the liquid from the tubing drains.

Other devices have also been developed for draining the liquid, which are installed above the PTSEN check valve. These include the so-called prompters, which make it possible to measure the annulus pressure at the pump descent depth with a downhole pressure gauge lowered into the tubing, and establish communication between the annular space and the measuring cavity of the pressure gauge.

It should be noted that the engines are sensitive to the cooling system, which is created by the fluid flow between the casing string and the SEM body. The speed of this flow and the quality of the liquid affect the temperature regime of the SEM. It is known that water has a heat capacity of 4.1868 kJ/kg-°C, while pure oil is 1.675 kJ/kg-°C. Therefore, when pumping out watered well production, the conditions for cooling the SEM are better than when pumping clean oil, and its overheating leads to insulation failure and engine failure. Therefore, the insulating qualities of the materials used affect the duration of the installation. It is known that the heat resistance of some insulation used for motor windings has already been brought up to 180 °C, and operating temperatures up to 150 °C. To control the temperature, simple electrical temperature sensors have been developed that transmit information about the temperature of the SEM to the control station via a power electric cable without the use of an additional core. Similar devices are available for transmitting constant information about the pressure at the pump intake to the surface. In case of emergency conditions, the control station automatically switches off the SEM.

The SEM is powered by electricity through a three-core cable, which is lowered into the well in parallel with the tubing. The cable is attached to the outer surface of the tubing with metal belts, two for each pipe. The cable works in difficult conditions. Its upper part is in a gaseous environment, sometimes under significant pressure, the lower part is in oil and is subjected to even greater pressure. When lowering and raising the pump, especially in deviated wells, the cable is subjected to strong mechanical stresses (clamps, friction, jamming between the string and tubing, etc.). The cable transmits electricity at high voltages. The use of high voltage motors makes it possible to reduce the current and hence the cable diameter. However, the cable for powering a high-voltage motor must also have a more reliable, and sometimes thicker, insulation. All cables used for UPTsEN are covered with an elastic galvanized steel tape on top to protect against mechanical damage. The need for cable placement outer surface PTSEN reduces the dimensions of the latter. Therefore, a flat cable is laid along the pump, having a thickness of about 2 times less than the diameter of a round one, with the same sections of conductive cores.

All cables used for UTSEN are divided into round and flat. Round cables have rubber (oil-resistant rubber) or polyethylene insulation, which is displayed in the cipher: KRBK means armored rubber round cable or KRBP - rubber armored flat cable. When using polyethylene insulation in the cipher, instead of the letter P, P is written: KPBK - for a round cable and KPBP - for a flat one.

The round cable is attached to the tubing, and the flat cable is attached only to the lower pipes of the tubing string and to the pump. The transition from a round cable to a flat cable is spliced ​​by hot vulcanization in special molds, and if such a splice is of poor quality, it can serve as a source of insulation failure and failures. Recently, they are switching only to flat cables running from the SEM along the tubing string to the control station. However, the manufacture of such cables is more difficult than round ones (Table 11.1).

There are some other types of polyethylene insulated cables not mentioned in the table. Cables with polyethylene insulation are 26 - 35% lighter than cables with rubber insulation. Cables with rubber insulation are designed for use at a rated voltage of electric current not exceeding 1100 V, at ambient temperatures up to 90 ° C and pressure up to 1 MPa. Cables with polyethylene insulation can operate at voltages up to 2300 V, temperatures up to 120 °C and pressures up to 2 MPa. These cables are more resistant to gas and high pressure.

All cables are armored with corrugated galvanized steel tape for strength.

The primary windings of three-phase transformers and autotransformers are always designed for the voltage of the commercial power supply, i.e. 380 V, to which they are connected through control stations. The secondary windings are designed for the operating voltage of the respective motor to which they are connected by cable. These operating voltages in various PEDs vary from 350V (PED10-103) to 2000V (PED65-117; PED125-138). To compensate for the voltage drop in the cable from the secondary winding, 6 taps are made (in one type of transformer there are 8 taps), which allow you to adjust the voltage at the ends of the secondary winding by changing the jumpers. Changing the jumper by one step increases the voltage by 30 - 60 V, depending on the type of transformer.

All non-oil-filled, air-cooled transformers and autotransformers are covered with a metal casing and are designed for installation in a sheltered place. They are equipped with an underground installation, so their parameters correspond to this SEM.

Recently, transformers have become more widespread, as this allows you to continuously control the resistance of the secondary winding of the transformer, cable and stator winding of the SEM. When the insulation resistance drops to the set value (30 kOhm), the unit automatically switches off.

With autotransformers having a direct electrical connection between the primary and secondary windings, such insulation control cannot be carried out.

Transformers and autotransformers have an efficiency of about 98 - 98.5%. Their mass, depending on the power, ranges from 280 to 1240 kg, dimensions from 1060 x 420 x 800 to 1550 x 690 x 1200 mm.

The operation of the UPTsEN is controlled by the control station PGH5071 or PGH5072. Moreover, the control station PGH5071 is used for autotransformer power supply of the SEM, and PGH5072 - for transformer. Stations PGH5071 provide instant shutdown of the installation when the current-carrying elements are shorted to the ground. Both control stations provide the following possibilities for monitoring and controlling the operation of the UTSEN.

1. Manual and automatic (remote) switching on and off of the unit.

2. Automatic switching on of the installation in the self-start mode after the restoration of the voltage supply in the field network.

3. Automatic operation installations in periodic mode (pumping out, accumulation) according to the established program with a total time of 24 hours.

4. Automatic switching on and off of the unit depending on the pressure in the discharge manifold when automated systems group collection of oil and gas.

5. Instantaneous shutdown of the installation in case of short circuits and overloads in current strength by 40% exceeding the normal operating current.

6. Short-term shutdown for up to 20 s when the SEM is overloaded by 20% of the nominal value.

7. Short-term (20 s) shutdown in case of failure of the fluid supply to the pump.

The doors of the control station cabinet are mechanically interlocked with a switch block. There is a trend towards switching to non-contact, hermetically sealed control stations with semiconductor elements, which, as experience has shown, are more reliable, not affected by dust, moisture and precipitation.

Control stations are designed for installation in shed-type rooms or under a canopy (in the southern regions) at an ambient temperature of -35 to +40 °C.

The mass of the station is about 160 kg. Dimensions 1300 x 850 x 400 mm. The UPTsEN delivery set includes a drum with a cable, the length of which is determined by the customer.

During the operation of the well, for technological reasons, the depth of the pump suspension has to be changed. In order not to cut or build up the cable with such suspension changes, the length of the cable is taken according to the maximum suspension depth of a given pump and, at shallower depths, its excess is left on the drum. The same drum is used for winding the cable when lifting the PTSEN from the wells.

With a constant suspension depth and stable pumping conditions, the end of the cable is tucked into the junction box, and there is no need for a drum. In such cases, during repairs, a special drum is used on a transport trolley or on a metal sledge with a mechanical drive for constant and uniform pulling of the cable extracted from the well and winding it onto the drum. When the pump is lowered from such a drum, the cable is evenly fed. The drum is electrically driven with reverse and friction to prevent dangerous tensions. At oil producing enterprises with a large number of ESPs, a special transport unit ATE-6 based on the KaAZ-255B cargo all-terrain vehicle is used to transport a cable drum and other electrical equipment, including a transformer, pump, engine and hydraulic protection unit.

For loading and unloading the drum, the unit is equipped with folding directions for rolling the drum onto the platform and a winch with a pulling force on the rope of 70 kN. The platform also has a hydraulic crane with a lifting capacity of 7.5 kN with an outreach of 2.5 m.

Typical wellhead fittings equipped for PTSEN operation (Figure 5) consist of a crosspiece 1, which is screwed onto the casing string.

Figure 5 - Wellhead fittings equipped with PTSEN

The cross has a detachable insert 2, which takes the load from the tubing. A seal made of oil-resistant rubber 3 is applied to the liner, which is pressed by a split flange 5. Flange 5 is pressed by bolts to the flange of the cross and seals the cable outlet 4.

The fittings provide for the removal of annular gas through the pipe 6 and the check valve 7. The fittings are assembled from unified units and stopcocks. It is relatively easy to rebuild for wellhead equipment when operating with sucker rod pumps.

Application area ESP- these are high-rate watered, deep and inclined wells with a flow rate of 10 ¸ 1300 m 3 / day and a lift height of 500 ¸ 2000m. overhaul period ESP up to 320 days or more.

Units of submersible centrifugal pumps in modular design types UETsNM and UETsNMK are designed for pumping out oil well products containing oil, water, gas and mechanical impurities. Type settings UETsNM have the usual execution, and the type UETsNMK- corrosion resistant.

The installation (Fig. 24) consists of a submersible pumping unit, a cable line lowered into the well on tubing, and ground electrical equipment (transformer substation).

The submersible pumping unit includes an engine (an electric motor with hydraulic protection) and a pump, above which a check and drain valve is installed.

Depending on the maximum transverse dimension of the submersible unit, the installations are divided into three conditional groups - 5; 5A and 6:

- installations of group 5 with a transverse dimension of 112 mm are used in wells with a casing string with an internal diameter of at least 121.7 mm;

- installations of group 5A with a transverse dimension of 124 mm - in wells with an internal diameter of at least 130 mm;

- installations of group 6 with a transverse dimension of 140.5 mm - in wells with an internal diameter of at least 148.3 mm.

Conditions of applicability ESP for pumped media: liquid with a content of mechanical impurities not more than 0.5 g/l, free gas at the pump intake not more than 25%; hydrogen sulfide not more than 1.25 g/l; water not more than 99%; the pH value (pH) of formation water is within 6¸8.5. The temperature in the area where the electric motor is located is not more than +90°C (special heat-resistant version up to +140°C).

Installation cipher example − UETsNMK 5-125-1300 means: UETsNMK— installation of a modular and corrosion-resistant electric centrifugal pump; 5 - pump group; 125 - supply, m 3 / day; 1300 - developed pressure, m of water. Art.

On fig. 24 shows a diagram of the installation of submersible centrifugal pumps in a modular design, representing a new generation of equipment of this type, which allows you to individually select the optimal layout of the installation for wells in accordance with their parameters from a small number of interchangeable modules.

Installations (in Fig. 24, the scheme of NPO "Borets", Moscow) ensure the optimal selection of the pump to the well, which is achieved by the presence of a large number of pressures for each supply. The pressure step of the installations is from 50¸100 to 200¸250 m, depending on the supply, in the intervals indicated in Table. 7 basic setting data.

Table 7

Name of installations	Minimum (internal) diameter of the production string, mm	Transverse dimension of the installation, mm	Feed m 3 / day		Engine power, kW	Gas separator type
UETsNMK5-80
UETsNMK5-125
UETsNM5A-160
UETsNM5A-250
UETsNMK5-250
UETsNM5A-400
UETsNMK5A-400
	144.3 or 148.3	137 or 140.5
UETsNM6-1000

Mass-produced ESP have a length of 15.5 to 39.2 m and a weight of 626 to 2541 kg, depending on the number of modules (sections) and their parameters.

In modern installations, from 2 to 4 modules-sections can be included. A package of steps is inserted into the section housing, which is impellers and guide vanes assembled on the shaft. The number of steps ranges from 152¸393. The inlet module represents the base of the pump with intake holes and a mesh filter through which fluid from the well enters the pump. At the top of the pump is a fishing head with a check valve, to which the tubing is attached.

Pump ( ETsNM)— submersible centrifugal modular multistage vertical design.

Pumps are also divided into three conditional groups - 5; 5A and 6. Case diameters of group 5¸92 mm, group 5A - 103 mm, group 6 - 114 mm.

The module-section of the pump (Fig. 25) consists of a housing 1 , shaft 2 , packages of steps (impellers - 3 and guide vanes 4 ), upper bearing 5 , lower bearing 6 , top axial support 7 , heads 8 , grounds 9 , two edges 10 (serve to protect the cable from mechanical damage) and rubber rings 11 , 12 , 13 .

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 shoulder of the guide vane. Partially, the 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. The torque is transmitted from the shaft to the wheels by a brass (L62) key, which is included in 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 (Fig. 25) and base 9 , and from above through the housing of the upper bearing are clamped in the housing.

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.

Shafts of section modules and input modules for conventional pumps are made of combined corrosion-resistant high-strength steel OZKh14N7V and are marked “NZh” at the end. "M".

Shafts of modules-sections of all groups of pumps, having the same casing lengths of 3, 4 and 5 m, are unified.

Shafts of section modules are interconnected, a section module is connected to the shaft of the input module (or a gas separator shaft), the shaft of the input module is connected with the engine hydroprotection shaft by means of splined couplings.

The connection of the modules to each other and the input module with the motor is flanged. Sealing of connections (except for the connection of the input module with the engine and the input module with the gas separator) is carried out with rubber rings.

To pump out formation fluid containing more than 25% (up to 55%) of free gas at the grid of the pump input module, a pumping module - gas separator is connected to the pump (Fig. 26).

Rice. 26. Gas separator:

1 - head; 2 - translator; 3 - separator; 4 - frame; 5 - shaft; 6 - lattice; 7 - guide apparatus; 8 - Working wheel; 9 - auger; 10 - bearing; 11 ‑ base

The gas separator is installed between the input module and the section module. The most efficient gas separators are of the centrifugal type, in which the phases are separated in the 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 ejected into the annulus. Gas separators of the MNG series have a limit flow of 250¸500 m 3 /day, a separation factor of 90%, and a weight of 26 to 42 kg.

The engine of the submersible pumping unit consists of an electric motor and hydraulic protection. Electric motors (Fig. 27) are submersible three-phase short-circuited two-pole oil-filled conventional and corrosion-resistant versions of the unified series of PEDU and in the usual version of the PED series of modernization L. Hydrostatic pressure in the operating area is not more than 20 MPa. Rated power from 16 to 360 kW, rated voltage 530¸2300 V, rated current 26¸122.5 A.

Rice. 27. PEDU series electric motor:

1 - coupling; 2 - lid; 3 - head; 4 - heel; 5 - thrust bearing; 6 - cable entry cover; 7 - cork; 8 – cable entry block; 9 - rotor; 10 - stator; 11 – filter; 12 - base

Hydroprotection (Fig. 28) of SEM motors is designed to prevent the penetration of formation fluid into the internal cavity of the electric motor, to compensate for changes in the volume of oil in the internal cavity due to the temperature of the electric motor and to transfer torque from the electric motor shaft to the pump shaft.

Rice. 28. Waterproofing:

a- open type; b- closed type

BUT– upper chamber; B- down Cam;

1 - head; 2 – end seal; 3 – top nipple; 4 - frame; 5 - middle nipple; 6 - shaft; 7 - lower nipple; 8 - base; 9 - connecting tube; 10 - diaphragm

Hydroprotection consists either of one protector, or of a protector and a compensator. There are three versions of the hydroprotection.

The first one consists of protectors P92, PK92 and P114 (open type) from two chambers. The upper chamber is filled with a heavy barrier liquid (density up to 2 g/cm 3 , immiscible with formation fluid and oil), the lower chamber is filled with MA-PED oil, which is the same as the cavity of the electric motor. The chambers are communicated by a tube. Changes in the volumes of the liquid dielectric in the engine are compensated by the transfer of the barrier liquid in the hydraulic protection from one chamber to another.

The second one consists of protectors P92D, PK92D and P114D (closed type), in which rubber diaphragms are used, their elasticity compensates for the change in the volume of the liquid dielectric in the engine.

The third - hydraulic protection 1G51M and 1G62 consists of a protector placed above the electric motor and a compensator attached to the bottom of the electric motor. The mechanical seal system provides protection against ingress of formation fluid along the shaft into the electric motor. The transmitted power of hydraulic protection is 125¸250 kW, weight is 53¸59 kg.

The thermomanometric system TMS - 3 is designed to automatically control the operation of a submersible centrifugal pump and protect it from abnormal operating modes (at reduced pressure at the pump intake and elevated temperature of the submersible motor) during well operation. There are underground and ground parts. Controlled pressure range from 0 to 20 MPa. The operating temperature range is from 25 to 105 ° C.

Total weight 10.2 kg (see Fig. 24).

The cable line is a cable assembly wound on a cable drum.

The cable assembly consists of the main cable - round PKBK (cable, polyethylene insulation, armored, round) or flat - KPBP (Fig. 29), a flat cable attached to it with a cable entry sleeve (extension cable with sleeve).

Rice. 29. Cables:

a– round; b- flat; 1 - lived; 2 – isolation; 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 in 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 gland K38 (K46) of round type. In the metal case of the coupling, the insulated cores of the flat cable are hermetically sealed with a rubber seal.

Plug-in lugs are attached to the conductive wires.

The round cable has a diameter of 25 to 44 mm. The size of the flat cable is from 10.1x25.7 to 19.7x52.3 mm. Nominal building length 850, 1000¸1800m.

Complete devices of the ShGS5805 type provide switching on and off of submersible motors, remote control from the control room and program control, operation in manual and automatic modes, shutdown in case of overload and deviation of the mains voltage above 10% or below 15% of the nominal, current and voltage control, as well as an external light signaling of an emergency shutdown (including with a built-in thermometric system).

Integrated transformer substation for submersible pumps - KTPPN is designed to supply electricity and protect electric motors of submersible pumps from single wells with a capacity of 16¸125 kW inclusive. Rated high voltage 6 or 10 kV, medium voltage regulation limits from 1208 to 444 V (TMPN100 transformer) and from 2406 to 1652 V (TMPN160). Weight with transformer 2705 kg.

Complete transformer substation KTPPNKS is designed for power supply, control and protection of four centrifugal electric pumps with electric motors 16¸125 kW for oil production in well clusters, power supply for up to four electric motors of pumping units and mobile pantographs during repair work. KTPPNKS is designed for use in the conditions of the Far North and Western Siberia.

The delivery set of the installation includes: a pump, a cable assembly, a motor, a transformer, a complete transformer substation, a complete device, a gas separator and a set of tools.