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WO2009077714A1 - Ensemble de pompe submersible - Google Patents

Ensemble de pompe submersible Download PDF

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Publication number
WO2009077714A1
WO2009077714A1 PCT/GB2008/003966 GB2008003966W WO2009077714A1 WO 2009077714 A1 WO2009077714 A1 WO 2009077714A1 GB 2008003966 W GB2008003966 W GB 2008003966W WO 2009077714 A1 WO2009077714 A1 WO 2009077714A1
Authority
WO
WIPO (PCT)
Prior art keywords
pump
motor
cable
well
assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2008/003966
Other languages
English (en)
Inventor
Mark Joseph Denny
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BP Exploration Operating Co Ltd
Original Assignee
BP Exploration Operating Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BP Exploration Operating Co Ltd filed Critical BP Exploration Operating Co Ltd
Publication of WO2009077714A1 publication Critical patent/WO2009077714A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/20—Flexible or articulated drilling pipes, e.g. flexible or articulated rods, pipes or cables
    • E21B17/206—Flexible or articulated drilling pipes, e.g. flexible or articulated rods, pipes or cables with conductors, e.g. electrical, optical
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B23/00—Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells
    • E21B23/02—Apparatus for displacing, setting, locking, releasing or removing tools, packers or the like in boreholes or wells for locking the tools or the like in landing nipples or in recesses between adjacent sections of tubing
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
    • E21B43/121—Lifting well fluids
    • E21B43/128—Adaptation of pump systems with down-hole electric drives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/04—Flexible cables, conductors, or cords, e.g. trailing cables
    • H01B7/046—Flexible cables, conductors, or cords, e.g. trailing cables attached to objects sunk in bore holes, e.g. well drilling means, well pumps

Definitions

  • the present invention relates to a submersible pump assembly.
  • Submersible pump assemblies are used widely to artificially lift fluids from well bores where the well bore pressure is insufficient to lift the fluids to the surface without assistance. Without such assistance, the production rate of a well will fall and ultimately the well will die.
  • a common submersible pump assembly includes a centrifugal pump powered by an induction motor, the assembly being attached to and carried on the lower end of the production tubing in the well bore.
  • the motor is powered by way of an electrical cable extending along and attached to the external surface of the production tubing.
  • Induction motors tend to have a short, wide construction. This, however, cannot be accommodated in the narrow bore of the well casing, production tubing or well bore. Accordingly, the design of the induction motor has to be compromised in order to fit the motor into the well casing or production tubing. This results in the motor being relatively long and thin. These design compromises make the induction motors less reliable and therefore more susceptible to failure, increasing the frequency of workovers needed to replace the failed equipment. Additionally, induction motors are inefficient since the generation of the magnetic flux in the rotor results in energy losses.
  • an electrical cable may be clamped to the exterior of a tube or may be held or supported within a tube, the tube being coiled on a drum for storage.
  • the tube bears the load of the apparatus suspended therefrom.
  • the tube must be of sufficient tensile strength to support its own weight and that of a submersible pump assembly suspended therefrom. Consequently, coiled tubing may be more rigid and may have a considerably larger minimum bending radius than a cable of equivalent tensile strength.
  • a reel of coiled tubing may typically have a considerably larger diameter than a drum of cable of equivalent tensile strength.
  • the large size of a coiled tubing reel may mean that it is relatively expensive to move to a site and rig up over a well.
  • the bending radius of tubing is generally limited to the radius greater than that at which the tube wall tends to buckle.
  • a distinction between coiled tubing and cable may be made by comparing the minimum bending radius to which an assembly may be repeatedly deformed without exceeding the elastic limit of the material, e.g. as evidenced by local buckling or the acquisition of a permanent set.
  • Such an electro-mechanical cable may contain tubular elements.
  • the tubular elements are relatively thin walled and do not bear the full weight of the cable assembly and the applied load; hence, they may be flexible and compliant with the remainder of the cable.
  • Coiled tubing may acquire a permanent set on the drum. Therefore, what is known in the industry as an "injector head” assembly may be required in order to straighten the tubing prior to injecting it into a well. Such an assembly may also allow tension to be maintained on tubing to prevent the tubing uncoiling from the drum.
  • the tubing may be so highly stressed in bending that it acts like a watch spring if the drum and tube are not restrained.
  • US 4,665,281 relates to a high temperature flexible tubing cable system, which is particularly suitable for use in applications requiring submersible pumps and the like.
  • the flexible tubing cable assembly has an outer sheath of flexible thin wall metal tubing with one or more conductors therein, each of the conductors having a first layer of a first dielectric and a second layer of a second dielectric, with a third dielectric material filling the space between the one or more conductors and the interior of the tubing.
  • the person skilled in the art would understand that the flexible tubing cable assembly of US 4,665,281 constitutes an electric cable encapsulated within coiled tubing, as opposed to a cable, e.g. an electro-mechanical cable, per se.
  • US 3411454 relates to a pump installation in which an electric pump is suspended in a well casing from a wire-line.
  • the patent teaches a mechanical system for securing the pump in the well.
  • the system is activated when the pump has built up sufficient pressure in the well above.
  • Expandable slips engage the casing so that the casing can support the weight of the pump and the weight of the fluid column above the pump, thereby relieving longitudinal stress on the cable.
  • this system has not been taken up in the industry.
  • One problem with this system is that until the pressure required to activate the expandable slips is reached, the pump is not restrained and so the torque load is not resisted and the assembly will spin.
  • the cable is torqued up and released which can wear/damage the cable and/or the seals between the pump and the well casing.
  • WO 2004/113670 describes a method of pumping well bore fluids comprising the steps of installing an electric submersible pump in a well bore and operating the pump at more than 4500 rpm to pump the well bore fluid.
  • a permanent magnet motor can be used.
  • high operation speeds such as this introduce problems such as increased frictional losses and mechanical wear, particularly since well fluids often contain small solid particles.
  • US 6413065 describes a modular downhole pump including a gear module for transferring power to the pump from a sucker rod or a downhole motor and a rotor module.
  • the rotor module includes a pair of counter-rotating, interleaved rotors split into an upper pair and a lower pair which pump fluids in opposite directions within the rotor module.
  • the rotor modules may be configured to increase the pressure capacity or the volume capacity of the pump and may be connected in series to achieve a desired volume and pressure output.
  • the invention solves or at least mitigates the problems encountered in using typical known submersible pump assemblies. Suspending the pump and motor on an electromechanical cable allows the pump and motor to be deployed and raised to the surface as necessary without the need for a drilling or work-over rig. This reduces the total repair time from weeks to days compared with assemblies which use rigid or coiled tubing to deploy the pump and motor, whilst simultaneously significantly reducing the cost.
  • an electric submersible pump using electro-mechanical cable rather than rigid or coiled tubing.
  • electro-mechanical cable may contain tubular elements.
  • the tubular elements are relatively thin walled and typically do not bear the full weight of the cable assembly and the applied load; hence, they may be flexible and compliant with the remainder of the cable.
  • Permanent magnet motors may be significantly more efficient than conventional induction motors. For instance, an induction motor may have an efficiency of around 85%, whereas a permanent magnet motor may have an efficiency of around 95%. Hence, the losses associated with a permanent magnet motor may be significantly lower, say three times lower, than with a conventional induction motor. Therefore, the permanent magnet motor may require significantly less cooling, in use, and/or may be operable with lower thermal gradients.
  • the pump assembly of the present invention may be used to pump fluids comprising up to and more than 70% gas by volume.
  • the ratio of gas to liquid is not fixed, but will change with pressure. Typically, as the pressure in a well decreases, the ratio of gas to liquid will increase.
  • the pump assembly of the present invention may be used to pump fluids having high gas to liquid ratios, a well may be produced at a lower pressure using it than may have otherwise been possible. This, in turn, may allow a well to produce more flow (liquid as well as gas).
  • an assembly having a positive displacement pump and a permanent magnet motor can be very much shorter than conventional assemblies using induction motors or centrifugal pumps.
  • the permanent magnet motor can be significantly shorter than an induction motor, whilst achieving the same power output.
  • a positive displacement pump transports a fluid from the intake to the discharge at uniform velocity and the resulting pressure is determined by pump leakage, not by the number of pumping stages. Thus the pump can be much shorter.
  • the ability to significantly reduce the length of the assembly allows low cost intervention into both dry tree and subsea wells. To date, intervention in live wells through the use of a lubricator and pressure control equipment has not been possible for electrical submersible pump assemblies due to the length of the assemblies. However, such interventions are now advantageously possible with the present invention.
  • the pump assembly of the present invention can pump a broad range of fluid types, from viscous heavy oils, to gas with traces of condensate and/or water.
  • the use of a twin screw pump in particular enables the assembly to be used in environments where there is a high gas to liquid ratio since it does not suffer the same problems as centrifugal pumps. Although a twin screw pump does accelerate liquid to the extremities of each screw, the liquid then forms a viscous seal with the other screw or the housing, allowing gas to be efficiently transported to the discharge.
  • twin screw positive displacement pump in the invention can allow a sub-surface safety valve to be omitted from situations where one would otherwise be necessary. This is because there is no flow path through the pump when it is stationary.
  • the invention finds particular success in subsea wells.
  • the requirement for regular interventions to repair or service conventional pumping assemblies renders use of conventional electric submersible pumping assemblies unsuitable for subsea wells.
  • subsea wells are often produced under gas lift, but this is inefficient and expensive to operate, and can result in considerable volumes of oil being left un-recovered.
  • the present invention has improved reliability and also does not require large support vessels such as semi-submersible drilling rigs to conduct servicing or repair of the assembly. The invention therefore opens up the use of electric submersible pumping assemblies to subsea wells.
  • a flow of fluid past the motor may be better maintained, in use, beneficially cooling the motor.
  • the fluid flowing past the motor may typically be at or close to the pump discharge pressure, which pressure may be relatively high.
  • the cooling effect of the fluid may be beneficially increased, as higher fluid pressures will reduce the gas to liquid volume ratio, thereby increasing the effective heat capacity of the fluid.
  • coupling the motor between the electro-mechanical cable and the pump has the advantage that the electrical conductor(s) in the electro-mechanical cable can be connected directly to the motor and need not be arranged to pass through or around the pump.
  • this arrangement may be more reliable than known systems which arrange the pump between the motor and coiled tubing or wire, and also may be shorter than known systems which arrange the motor between the coiled tubing and the pump as those systems require a sealing unit between the motor and pump as well as a thrust bearing unit below the pump. In particular, such a sealing unit may not be required.
  • the electro-mechanical cable may be provided with a connector for coupling the pump and motor to the cable.
  • the motor may be provided with a connector for this purpose.
  • the electro-mechanical cable preferably comprises a core, having at least one electrical conductor, and an outer sheath around the core capable of supporting the weight of the cable as well as the weight of the motor and the pump.
  • the electrical conductor can be a copper wire or a group of copper wires.
  • One or more conductors/wires for transmitting data and/or control instructions can also be included in the core.
  • the outer sheath may include one or two layers of spiral wound wires, preferably steel armour wires. Where two layers are used, the layers are advantageously contra wound. This can balance torque under an applied tensile load.
  • the electro-mechanical cable further comprises a conduit for transmitting a fluid along the cable.
  • the conduit can extend through the core of the cable.
  • the pump outlet can be in communication with the conduit for discharging fluid directly into the conduit. This can be advantageous when the assembly is used as a vertical separator as described below.
  • the motor is a permanent magnet motor. It can be a DC motor or an AC motor, for example a single phase or three-phase AC motor. DC motors are beneficial since they can provide high starting torque which has been found to be useful for powering positive displacement pumps, particularly in a well that produces solids (e.g. sand particles).
  • DC motors can require more servicing than AC motors
  • the invention allows for easy removal of the motor from the well for servicing, and the advantages of high starting torque outweigh the risk of possible increased servicing.
  • DC motors and single phase AC motors have been found to be advantageous since the electro-mechanical cable can be narrower as only a single conductor is required. This is beneficial both because the cable can be lighter and also since sealing around a narrow cable is easier.
  • the assembly further includes a packer which can be positioned in a well, for example it can be mountable on the casing or on the production tubing of a well.
  • a packer By providing the packer on the casing or production tubing, the motor and pump can be lowered or raised independently of the packer.
  • the packer is engageable with the pump or the motor, or an element associated with the pump or motor, to hold the pump and motor at a desired location in the well.
  • the packer may be sealingly engageable with the pump or motor, or an element associated with the pump or motor, so as to seal a region of the well below the packer from a region of the well above the packer.
  • the pump, the motor and/or an element associated with the pump or the motor is provided with first engaging means for coupling to second engaging means provided on the packer.
  • the engaging means may comprise torque resisting means.
  • the first engaging means can engage the second engaging means when the pump and motor are lowered to the desired position in the well.
  • the torque resisting means prevent the pump and motor rotating with respect to the packer, for example when the pump and motor are activated. This prevents twisting of the electro-mechanical cable.
  • one of the first and second engaging means may comprise one or more projections such as pins or ribs.
  • the other engaging means may comprise one or more recesses such as slots into which said projection can extend to prevent rotational movement of the pump and motor with respect to the packer.
  • said recess may further be provided with a cammed surface for guiding said projection into said recess.
  • the motor and pump can be circumferentially aligned with the packer as it is lowered.
  • the first engaging means may comprise axial movement resisting means which can engage the packer so as to resist axial separation of the pump and motor from the packer.
  • the axial direction is taken to be along the length of the local well bore.
  • the second engaging means of the packer may include means which co-operate with the axial movement resisting means of the first engaging means.
  • one of the first or second engaging means may include one or more projections such as fingers, clips or flanges for engaging one or more corresponding recesses on the other of the pump and the packer, such that axial movement of the projection out of the recess is resisted.
  • the first and second engaging means include torque resisting means and axial movement resisting means. This allows the pump and motor to be accurately and securely held in a desired position in the well.
  • the assembly further comprises a valve having an open condition and a closed condition, the valve being in the open condition when the pump is coupled to the packer or when the pump is in operation and the valve moving from the open condition to the closed condition when the pump stops operating or is separated from the packer. Accordingly, turning the pump off or removing the pump from the packer automatically closes the valve. Not only does this reduce the need for well kill when the pump assembly is removed from the well, but the valve moves between open and closed positions only as necessary and is not, therefore, subjected to unnecessary usage and wear.
  • the valve may be a one way valve. The valve can be removable so that it could be replaced if it leaks.
  • a method of pumping fluids from a well to a surface comprises the steps of: providing an electro-mechanical cable (1) capable of suspending a twin screw positive displacement pump and a permanent magnet motor in a well bore and of supplying electrical power to such a motor; coupling a twin screw pump (3) and a permanent magnet motor (2) to the electro-mechanical cable (1 ) such that the permanent magnet motor (2) is located between the cable (1) and the twin screw pump (3); deploying the electro-mechanical cable with the permanent magnet motor and twin screw pump suspended therefrom into a well bore and lowering the motor and pump to a desired location; activating the motor and therefore the pump and thereby pumping a fluid up the well bore.
  • the method of the invention does not require a drilling or work-over rig to deploy or retrieve the motor and pump.
  • the method can further comprise positioning a packer in the desired location in the well bore before the electro-mechanical cable, motor and pump are deployed. The motor and pump are lowered until the pump is located in the packer.
  • the cable, motor and pump can form an electrical submersible pump assembly having any of the features of the assembly described above in connection with the first aspect of the invention.
  • the cable, motor and pump are deployed and lowered into a production tubing located in the well bore, the production tubing carrying on its lower end a submersible pump assembly which has failed.
  • the invention can be used to put wells back into operation after a conventional pump assembly already located at the end of the production tubing has failed, without requiring the withdrawal of the production tubing.
  • the assembly of the invention can simply be lowered down the production tubing.
  • the failed pump assembly does not allow the passage of fluid unless it is turned on, a fluid passage can be created to allow fluid to flow despite the failed pump. For example, a hole can be punched in the production tubing above the failed pump.
  • the well is a gas well and the cable, motor and pump are deployed and lowered into a production tubing located in the gas well until the inlet of the pump is located below the end of the production tubing.
  • Liquid is allowed to collect at the base of the gas well in the region of the pump inlet, and the pump is activated so as to pump the liquid out of the well.
  • the liquid may be pumped up the production tubing, as described above, while the gas is allowed to flow between the production tubing and a casing lining the well bore.
  • the cable may be provided with a conduit extending there-through which is suitable for conducting fluids, especially liquids.
  • the discharge of the pump is in communication with the conduit for discharging fluids directly into the conduit. Accordingly, liquid can be pumped out of the well through the fluid conduit of the electromechanical cable, while gas flows up the production tubing.
  • the invention can advantageously avoid reduced production or killing of gas wells by water accumulation. Liquid, such as water, can be pumped up through the cable or the production tubing and out of the well, whilst not restricting the gas flowing respectively up the production tubing or the annulus between the production tubing and the casing. It is to be understood that some gas may also be drawn into the pump in this embodiment along with the liquid.
  • the invention has been found to be particularly advantageous in this embodiment since the positive displacement pump can transmit fluids having a high gas to liquid ratio through the pump and up the conduit in the cable.
  • centrifugal pumps tend to 'gas lock' at the high gas to liquid ratios encountered in a gas de-liquification application.
  • the pump may be operated continuously, for example in gas wells which continuously produce liquid.
  • the pump could be controlled to operate on demand when a predetermined level of liquid has accumulated or at the start of production.
  • a packer may be provided generally as described above, so as to prevent the pump assembly rotating. Where gas is allowed to flow up the tubing to casing annulus, the pump does not form a seal with the packer. Instead, the engagement between the pump and the packer allows gas to flow between the pump and the packer and up the annulus between the tubing and casing. Where gas is required to flow up the the production tubing, the pump can form a seal with the packer.
  • a nipple profile can be provided at the lower end of the production tubing such that, at some point in the future if de-liquification becomes necessary, the assembly may be connected to the nipple profile by way of a connector on the assembly.
  • the connection between the assembly and the nipple profile can remain unsealed if the gas is to flow up the annulus between the production tubing and the casing, or can be sealed to allow gas to flow into the production tubing if liquid is to be passed directly into the conduit in the cable.
  • the method can be a method of cleaning up an injection well, hi other words, the well into which the cable, motor and pump is deployed can be an injection well.
  • the invention can be used to pump a fluid up the injection well bore.
  • an injection well can periodically undergo a clean up operation in which accumulated drilling fluids, debris etc are removed.
  • the well is operated as an injection well again i.e. fluids are injected down the well bore again.
  • the invention can be used to quickly and cheaply clean up an injection well, thereby restoring and maximising the performance of the injection well.
  • the pump can be a bidirectional positive displacement pump.
  • a bidirectional pump can be selectively operated to pump fluid in either direction through the pump i.e. in a forwards direction and in a reverse direction which is opposite to the forwards direction.
  • the invention can therefore be used to pump a fluid up an injection well bore for a first period of time, and then used to pump a fluid down an injection well for a second period of time, thereby assisting injection.
  • the first and second periods can form a cycle which can be repeated.
  • Figure 1 shows a schematic diagram of an electric submersible pump assembly according to the invention
  • Figure 2 shows a cross-section through the electro-mechanical cable of the assembly shown in Figure 1 ;
  • Figure 3 shows part of the inner surface of the bore through the packer;
  • Figure 4 shows a schematic diagram of a further embodiment of the present invention.
  • Figure 5 shows a schematic diagram of yet a further embodiment of the present invention.
  • Figure 6 shows a cross-section through the electro-mechanical cable of the assembly shown in Figure 5.
  • the assembly includes an electro-mechanical cable (1) supporting a permanent magnet motor (2) and a twin screw positive displacement pump (3) in a well casing (7).
  • the cable (1) is connected to the motor (2) through a sealed connection (4).
  • seal unit (5) coupled between the motor (2) and pump (3) which prevents leakage of fluid between the pump and the motor.
  • a packer (6) is positioned within the well casing (7), though it could equally be positioned within a production tube in the same way.
  • the pump (3) is located within and extends through a seal bore of the packer such that the pump's inlet (8) is below the packer
  • a seal (10) in the seal bore seals off the region of the well below the packer from the region above the packer.
  • An automatic isolation valve (11) is located in the well casing (7) below the packer
  • the valve (11) is adapted to be in its open position when the pump is located in the packer and in its closed position when the pump is not located in the packer. In this way, the valve operates automatically to isolate the region of the well below the valve when the electric submersible pump assembly is not in position in the packer, for example when the assembly is lifted from the packer and subsequently from the well for servicing or the like.
  • valve is mechanically actuated, though it could alternatively be differential pressure/flow actuated upon starting the pump. Valves of this type are known in the field.
  • FIG. 2 shows the electro-mechanical cable (1) in more detail.
  • the cable has an outer armoured sheath and a core.
  • Each conductor (13) is covered by one or more layers of insulating material.
  • a filler material (14) such as EPDM, PTFE etc surrounds the conductors (13) and fills the internal region of the outer sheath.
  • the outer armoured sheath comprises two layers (12a, 12b) of spiral wound steel armour wires.
  • the two armour layers (12a, 12b) are contra wound to torque balance the cable under an applied tensile load.
  • the wires of the external layer (12b) are of a smaller diameter than the wires of the inner layer (12a).
  • the cable can be mounted on a reel at ground level and unwound from the reel for deployment, as is known in other applications which use cables or wires.
  • the spiral wound steel sheath ensures that the cable (1) is strong enough to support its own weight as well as the weight of the motor (2) and pump (3), and ensures that the cable is torque balanced.
  • the motor (2) is a three-phase permanent magnet AC motor and so it results in a higher degree of efficiency compared with induction motors as no rotor magnetising current is required and there are reduced copper losses.
  • the permanent magnet motor can also be significantly shorter than an induction motor whilst achieving the same power.
  • the twin screw pump may be of the type described in US 6413065 of Can-K Artificial Lift Systems, Inc. of Alberta, Canada.
  • the permanent magnet motor and the positive displacement pump work efficiently together compared with known assemblies using induction motors and centrifugal pumps.
  • the power developed by a motor increases linearly with rotational speed of the motor, whereas the power to drive a centrifugal pump increases as the cube of the rotational speed. Accordingly, a centrifugal pump only truly matches its motor at one speed. A slight change in the motor speed has a much larger effect on the centrifugal pump and so the motor can easily be underloaded or overloaded.
  • the power of a permanent magnet motor is matched to the power of a positive displacement pump across a wider speed range because the power to drive a positive displacement pump also increases almost linearly with speed. Also, the permanent magnet motor and the positive displacement pump are shorter than their typical counterparts (i.e.
  • the pump (3) is provided with means for engaging the packer (6) so as to hold the pump both axially and circumferentially in place with respect to the packer.
  • two pins (15) extend away from the pump and engage the packer.
  • the packer is formed with two slots (16) in the seal bore (only one slot shown in Figure 3) such that each pin (15) slides into one of the slots (16) as the pump (3) is lowered into the packer (6).
  • the pins (15) therefore sit in the slots (16) when the pump is in operation and the side walls of the slots prevent the pins, and therefore the pump, rotating.
  • Other numbers of pins and slots could be used.
  • each slot diverges so as to have a funnel-like configuration.
  • the side walls can act as cam surfaces (17) which guide the pins (15) as the pump (3) is lowered, so as to bring the pump into the correct orientation to allow the pins to enter the slots (16).
  • the pump (3) and packer (6) are also provided with a latch mechanism to hold the pump in the packer against the pressure of the formation fluids below the pump.
  • the packer is provided with a latch (19) that projects below the pump and into the recesses (18) when the pump is in the correct position with respect to the packer.
  • the latch (19) may be a snap ring or, as shown in Figure 1, fingers which have ends which project into the recesses. The fingers engage the recesses and act to hold the pump in the packer against the pressure of the formation fluids below.
  • the latch has some resilience which allows it to release the pump when a predetermined upward force is applied on the cable (1), enabling withdrawal of the pump from the packer.
  • the engaging means i.e. the pins (15) and the recesses (18)
  • the pump is located in the packer.
  • they may be provided on the motor or on an element associated with the pump or the motor, such as a collar or frame above or below the motor or the pump. In this way, the assembly can be arranged so that the pump is instead held above or below the packer.
  • the packer (6) is positioned in the well casing (20) in a manner well known to the skilled artisan so as to prevent circumferential or axial movement of the packer within the casing.
  • the electric submersible pump assembly described above allows for much easier deployment into, and withdrawal from, a well, and is also efficient and effective in operation.
  • a short amount of cable (1) is spooled off a reel carrying a length of the cable.
  • the connector (4) on the free end of the cable is used to connect the cable (1) to the motor (2).
  • the pump (3) is connected to the other side of the motor so that the motor is above the pump when the assembly is suspended in the well casing.
  • the pump (3) and motor (2) are lowered down the well, suspended from the cable (1).
  • the cable is spooled off the reel until the pump and motor reach the desired location in the well, at which point the pump (3) moves into engagement with the packer (6).
  • the pins (15) on the pump (3) slide along the cam surfaces (17) to bring the pump into the correct angular alignment to allow the pins to slide into the slots (16) on the packer.
  • the resilient fingers of the latch (19) on the packer (6) slip into the recesses (18) on the pump.
  • the isolation valve (11) automatically opens.
  • the pump is activated by sending current down the copper conductors (13) in the electro-mechanical cable (1) so as to operate the motor. Liquid is drawn into the pump inlet (8) and is pumped out the pump outlet (9), so as to assist the production of well fluids from the well. Fluids of up to and above 70% gas to liquid ratio can be pumped successfully and efficiently using the assembly.
  • the present invention it is possible to introduce the cable carrying the pump and motor into a live, pressurised well using a lubricator.
  • An adaptation of the above method can be used in injection wells.
  • the twin screw pump can be operated in reverse so as to pump fluid in the opposite direction i.e. downwards.
  • the electric submersible pump of the invention can be deployed into the injection well and operated for a period of time to remove accumulated drilling fluids and debris from the well. After sufficient drilling fluids and debris etc have been removed, operation of the pump is reversed so as to aid injection of fluids down the cleaned well.
  • an electric submersible pump assembly as described above is used to bring a well back into production after a conventional pumping assembly (21) comprising a centrifugal pump carried on the lower end of a production tubing (22) has failed.
  • the conventional assembly is powered via an electric cable (26) running along the outside of the production tubing and terminating into the side of the motor using a pothead (27).
  • the assembly is lowered into the production tubing (22).
  • a packer (6) as described above is positioned near the lower end of the production tubing before the pump (3) and motor (2) are lowered.
  • the failed centrifugal pump allows the passage of fluid despite it not being operational, fluid is drawn through the old pump by the new pump. If the failed assembly comprises a pump which does not allow the passage of fluid unless the pump is operating, a hole can be punched in the production tubing above the failed pump, thereby providing a fluid by-pass.
  • the assembly of this embodiment is the same as that described above in connection with Figures 1 to 3. Accordingly, once installed, the assembly of the invention can draw fluids through the failed pumping assembly (21) into the production tubing (22) and through the pump (3) of the present invention so as to pump the fluid to the surface.
  • This has particular advantage for many existing wells in which the pumping system already in place is of poor efficiency, is towards the end of its useful life, or has already failed.
  • the electric submersible pump assembly of this embodiment comprises similar components described above with respect to Figures 1 to 3 and so like reference numerals have been used.
  • the electric submersible pump assembly is used as a vertical separator to deliquify a gas well.
  • a production tubing (22) in a gas well carries gas from the bottom of the well to the surface.
  • a packer (29) prevents the gas flowing between the production tubing and the well casing.
  • Liquid (28) accumulates at the bottom of the well if the gas flow is insufficient to carry the liquid up the production tubing. If liquid builds up, gas production can be reduced and the well can eventually be killed.
  • a twin screw pump (3) and permanent magnet motor (2) are suspended from an electro-mechanical cable (1) as described above as shown in Figure 5.
  • the cable, shown in Figure 6, additionally comprises a fluid conduit (23) extending there-through for carrying a fluid to the surface, and the pump outlet pumps fluid directly into the fluid conduit (23) rather than out into the production tubing (22).
  • the pump inlet (8) is found at the end of an inlet conduit (24) extending down from the pump.
  • a packer (25) is provided in the production tubing (22) of an existing well to engage the pump (3) and hold it against axial and rotational movement as • described above.
  • the pump and the packer there is no seal between the pump and the packer so that gas can flow from the bottom of the well, between the pump and the packer and up the production tubing.
  • the motor (2) and pump (3) are lowered through the production tube (22) in the gas well until the motor and pump are near the bottom of the well, and specifically until the inlet conduit (24) reaches a region where liquid (28) collects.
  • Activation of the pump causes liquid from the bottom of the well to be drawn through the inlet (8) and up into the pump (3) and consequently up through the fluid conduit (23) extending through the electro-mechanical cable (1).
  • accumulation of liquid in the bottom of the well which could otherwise kill or severely restrict production from the gas well, is prevented.
  • Gas flowing from the formation is able to pass into the production tubing (22), flowing between the pump and the packer and passed the motor.
  • the liquid carried up the cable's conduit (23) can also have gas entrained therein, though this does not cause a problem for the twin screw pump as the pump can handle fluids having up to and above 70% gas to liquid ratio.
  • the pump is operated continuously so as to maintain a minimum level of liquid in the bottom of the well.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Mechanical Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

L'invention porte sur un ensemble de pompe submersible et sur un procédé pour élever artificiellement un fluide à partir d'un puits de forage à la surface. L'ensemble comprend une pompe à vis double (3), un moteur à aimant permanent (2) pour entraîner la pompe et un câble électromécanique (1), le câble électromécanique étant apte à suspendre la pompe et le moteur dans un puits de forage et à délivrer de l'énergie électrique au moteur, le moteur à aimant permanent (2) étant disposé entre le câble (1) et la pompe à vis double (3).
PCT/GB2008/003966 2007-12-19 2008-12-01 Ensemble de pompe submersible Ceased WO2009077714A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP07254955.3 2007-12-19
EP07254955A EP2077374A1 (fr) 2007-12-19 2007-12-19 Unité de pompe submersible

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WO2009077714A1 true WO2009077714A1 (fr) 2009-06-25

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WO2011156157A2 (fr) 2010-06-07 2011-12-15 Zeitecs (B.V/Inc.) Système de pompage à suspension par câble compact pour l'assèchement des puits de gaz
WO2012161596A1 (fr) * 2011-05-24 2012-11-29 Flexidrill Limited Mécanisme de commande
WO2011146949A3 (fr) * 2010-05-18 2013-04-25 Artificial Lift Company Limited Unité d'accouplement permettant le déploiement d'un dispositif modulaire entraîné électriquement dans un puits
WO2011153011A3 (fr) * 2010-06-04 2013-05-02 Zeitecs B.V. Système de pompage suspendu à un câble compact pour déploiement de lubrifiant
CN103628842A (zh) * 2013-08-13 2014-03-12 哈尔滨恒誉名翔科技有限公司 一种直驱式永磁同步电动机抽油系统
US9482078B2 (en) 2012-06-25 2016-11-01 Zeitecs B.V. Diffuser for cable suspended dewatering pumping system
WO2017156116A1 (fr) * 2016-03-11 2017-09-14 Baker Hughes Incorporated Moteur électrique hybride pour une pompe électrique submersible
US10030489B2 (en) 2013-08-27 2018-07-24 Exxonmobil Upstream Research Company Systems and methods for artificial lift via a downhole piezoelectric pump
US10087719B2 (en) 2015-12-11 2018-10-02 Exxonmobil Upstream Research Company Systems and methods for artificial lift subsurface injection and downhole water disposal
US10323644B1 (en) 2018-05-04 2019-06-18 Lex Submersible Pumps FZC High-speed modular electric submersible pump assemblies
US10385856B1 (en) 2018-05-04 2019-08-20 Lex Submersible Pumps FZC Modular electric submersible pump assemblies with cooling systems
US10480297B2 (en) 2016-12-09 2019-11-19 Exxonmobil Upstream Research Company Hydrocarbon wells and methods cooperatively utilizing a gas lift assembly and an electric submersible pump
US10480501B2 (en) 2017-04-28 2019-11-19 Exxonmobil Upstream Research Company Nested bellows pump and hybrid downhole pumping system employing same
US10648303B2 (en) 2017-04-28 2020-05-12 Exxonmobil Upstream Research Company Wireline-deployed solid state pump for removing fluids from a subterranean well
US10753185B2 (en) 2017-10-04 2020-08-25 Exxonmobil Upstream Research Company Wellbore plungers with non-metallic tubing-contacting surfaces and wells including the wellbore plungers
US11078775B2 (en) 2018-12-18 2021-08-03 Exxonmobil Upstream Research Company Acoustic pressure wave gas lift diagnostics
US11208875B2 (en) 2019-01-04 2021-12-28 Exxonmobil Upstream Research Company Method of conducting plunger lift operations using a sphere and sleeve plunger combination
US11286748B2 (en) 2016-11-15 2022-03-29 Exxonmobil Upstream Research Company Pump-through standing valves, wells including the pump-through standing valves, and methods of deploying a downhole device
US11326426B2 (en) 2019-05-29 2022-05-10 Exxonmobil Upstream Research Company Hydrocarbon wells including gas lift valves and methods of providing gas lift in a hydrocarbon well
US11365613B2 (en) 2018-12-07 2022-06-21 Exxonmobil Upstream Research Company Electrical submersible pump motor adjustment
US11519260B2 (en) 2018-12-13 2022-12-06 Exxonmobil Upstream Research Company Rod pump position measurement employing wave-based technologies
US11555388B2 (en) 2019-10-30 2023-01-17 Exxonmobil Upstream Research Company Self-adjusting gas lift system
US11762117B2 (en) 2018-11-19 2023-09-19 ExxonMobil Technology and Engineering Company Downhole tools and methods for detecting a downhole obstruction within a wellbore

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US8726980B2 (en) 2010-02-24 2014-05-20 Schlumberger Technology Corporation Permanent cable for submersible pumps in oil well applications
GB201017181D0 (en) * 2010-10-12 2010-11-24 Artificial Lift Co Ltd Permanent magnet motor and pump on umbilical
US9255474B2 (en) * 2012-07-09 2016-02-09 Baker Hughes Incorporated Flexibility of downhole fluid analyzer pump module
EP2941523A4 (fr) * 2013-01-02 2016-01-06 Services Petroliers Schlumberger Dispositif antirotation et procédé pour pompes submersibles électriques déployables alternatives
WO2015030931A2 (fr) * 2013-08-27 2015-03-05 Exxonmobil Upstream Research Company Corp-Urc-Sw359 Systèmes et procédés permettant une ascension artificielle par l'intermédiaire d'une pompe volumétrique de fond de trou
NO340781B1 (no) * 2013-11-18 2017-06-19 Nexans Kabel for nedihullspumpe
EP3077677B1 (fr) * 2013-12-03 2019-11-13 Q.E.D. Environmental Systems, Inc. Pompe de prélèvement d'eaux souterraines

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WO2011146949A3 (fr) * 2010-05-18 2013-04-25 Artificial Lift Company Limited Unité d'accouplement permettant le déploiement d'un dispositif modulaire entraîné électriquement dans un puits
US9074592B2 (en) * 2010-05-28 2015-07-07 Schlumberger Technology Corporation Deployment of downhole pump using a cable
US20110297397A1 (en) * 2010-05-28 2011-12-08 Schlumberger Technology Corporation Deployment of downhole pump using a cable
US8534366B2 (en) 2010-06-04 2013-09-17 Zeitecs B.V. Compact cable suspended pumping system for lubricator deployment
US8851165B2 (en) 2010-06-04 2014-10-07 Zeitecs B.V. Compact cable suspended pumping system for lubricator deployment
AU2011261686B2 (en) * 2010-06-04 2014-09-04 Zeitecs (B.V / Inc.) Compact cable suspended pumping system for lubricator deployment
WO2011153011A3 (fr) * 2010-06-04 2013-05-02 Zeitecs B.V. Système de pompage suspendu à un câble compact pour déploiement de lubrifiant
WO2011156157A3 (fr) * 2010-06-07 2012-12-06 Zeitecs (B.V/Inc.) Système de pompage à suspension par câble compact pour l'assèchement des puits de gaz
CN103154429A (zh) * 2010-06-07 2013-06-12 泽泰克斯有限公司 用于为气井排水的线缆悬置的紧凑型泵送系统
US8584761B2 (en) 2010-06-07 2013-11-19 Zeitecs B.V. Compact cable suspended pumping system for dewatering gas wells
US8408312B2 (en) 2010-06-07 2013-04-02 Zeitecs B.V. Compact cable suspended pumping system for dewatering gas wells
WO2011156157A2 (fr) 2010-06-07 2011-12-15 Zeitecs (B.V/Inc.) Système de pompage à suspension par câble compact pour l'assèchement des puits de gaz
WO2012161596A1 (fr) * 2011-05-24 2012-11-29 Flexidrill Limited Mécanisme de commande
US9482078B2 (en) 2012-06-25 2016-11-01 Zeitecs B.V. Diffuser for cable suspended dewatering pumping system
CN103628842A (zh) * 2013-08-13 2014-03-12 哈尔滨恒誉名翔科技有限公司 一种直驱式永磁同步电动机抽油系统
US10030489B2 (en) 2013-08-27 2018-07-24 Exxonmobil Upstream Research Company Systems and methods for artificial lift via a downhole piezoelectric pump
US10087719B2 (en) 2015-12-11 2018-10-02 Exxonmobil Upstream Research Company Systems and methods for artificial lift subsurface injection and downhole water disposal
WO2017156116A1 (fr) * 2016-03-11 2017-09-14 Baker Hughes Incorporated Moteur électrique hybride pour une pompe électrique submersible
US11286748B2 (en) 2016-11-15 2022-03-29 Exxonmobil Upstream Research Company Pump-through standing valves, wells including the pump-through standing valves, and methods of deploying a downhole device
US10480297B2 (en) 2016-12-09 2019-11-19 Exxonmobil Upstream Research Company Hydrocarbon wells and methods cooperatively utilizing a gas lift assembly and an electric submersible pump
US10760387B2 (en) 2017-04-28 2020-09-01 Exxonmobil Upstream Research Company Cooling systems and methods for downhole solid state pumps
US10480501B2 (en) 2017-04-28 2019-11-19 Exxonmobil Upstream Research Company Nested bellows pump and hybrid downhole pumping system employing same
US10648303B2 (en) 2017-04-28 2020-05-12 Exxonmobil Upstream Research Company Wireline-deployed solid state pump for removing fluids from a subterranean well
US10753185B2 (en) 2017-10-04 2020-08-25 Exxonmobil Upstream Research Company Wellbore plungers with non-metallic tubing-contacting surfaces and wells including the wellbore plungers
US10385856B1 (en) 2018-05-04 2019-08-20 Lex Submersible Pumps FZC Modular electric submersible pump assemblies with cooling systems
US10323644B1 (en) 2018-05-04 2019-06-18 Lex Submersible Pumps FZC High-speed modular electric submersible pump assemblies
US11762117B2 (en) 2018-11-19 2023-09-19 ExxonMobil Technology and Engineering Company Downhole tools and methods for detecting a downhole obstruction within a wellbore
US11365613B2 (en) 2018-12-07 2022-06-21 Exxonmobil Upstream Research Company Electrical submersible pump motor adjustment
US11519260B2 (en) 2018-12-13 2022-12-06 Exxonmobil Upstream Research Company Rod pump position measurement employing wave-based technologies
US11078775B2 (en) 2018-12-18 2021-08-03 Exxonmobil Upstream Research Company Acoustic pressure wave gas lift diagnostics
US11208875B2 (en) 2019-01-04 2021-12-28 Exxonmobil Upstream Research Company Method of conducting plunger lift operations using a sphere and sleeve plunger combination
US11326426B2 (en) 2019-05-29 2022-05-10 Exxonmobil Upstream Research Company Hydrocarbon wells including gas lift valves and methods of providing gas lift in a hydrocarbon well
US11555388B2 (en) 2019-10-30 2023-01-17 Exxonmobil Upstream Research Company Self-adjusting gas lift system

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