WO2020071915A1 - Method and downhole pump for pumping liquid through a wellbore - Google Patents

Method and downhole pump for pumping liquid through a wellbore

Info

Publication number
WO2020071915A1
WO2020071915A1 PCT/NL2019/050663 NL2019050663W WO2020071915A1 WO 2020071915 A1 WO2020071915 A1 WO 2020071915A1 NL 2019050663 W NL2019050663 W NL 2019050663W WO 2020071915 A1 WO2020071915 A1 WO 2020071915A1
Authority
WO
WIPO (PCT)
Prior art keywords
pump
tubular
wellbore
actuator
liquid
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/NL2019/050663
Other languages
French (fr)
Inventor
Thomas Walburgis Bakker
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.)
Huisman Equipment BV
Original Assignee
Itrec BV
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 Itrec BV filed Critical Itrec BV
Publication of WO2020071915A1 publication Critical patent/WO2020071915A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B43/00—Machines, pumps, or pumping installations having flexible working members
    • F04B43/08—Machines, pumps, or pumping installations having flexible working members having tubular flexible members
    • F04B43/10—Pumps having fluid drive
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B47/00—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
    • F04B47/02—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level
    • F04B47/04—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level the driving means incorporating fluid means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B47/00—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
    • F04B47/06—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps having motor-pump units situated at great depth
    • F04B47/08—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps having motor-pump units situated at great depth the motors being actuated by fluid

Definitions

  • This invention relates to a downhole pump and a method for pumping liquid through a wellbore.
  • the invention in particular relates to a unique method and a downhole pump of unique features to pump wellbore liquids, e.g. hydrocarbons or water from subsurface reservoirs communicating with the earth’s surface by way of a wellbore.
  • wellbore liquids e.g. hydrocarbons or water from subsurface reservoirs communicating with the earth’s surface by way of a wellbore.
  • the method and the downhole pump according to the claimed invention can be configured to pump well bore liquids through a wellbore out of a subsurface reservoir, and can be configured to pump well bore liquids through a wellbore into a subsurface reservoir.
  • hydrocarbons to the surface.
  • the method and equipment chosen depend upon the depth of the well and of course the cost involved.
  • a typical method of bringing liquids to the surface is by means of an electrically powered submersible pump.
  • the pump together with its driving motor, is lowered down the wellbore to the bottom of the well. Power is transmitted through an electrical cable from a surface control box. The pressure created by the pump then forces the wellbore liquid to the surface.
  • the pump in particular those components of the pump that are in direct contact with the wellbore liquids, is subject to the aggressive, in particular corrosive, character of the wellbore liquid and to high temperatures.
  • the pump has to be lifted from the well and the cables have to be removed.
  • a further problem is that pumps are often relatively bulky and there are occasions when they cannot be placed where they are most needed. In such cases the pump may have to be situated in a less convenient location in which case liquid to be moved has to be piped to and from the pump and this can introduce other difficulties.
  • the present invention is directed to a pump which not only reduces the disadvantages of many existing pumps but in addition provides other important advantages.
  • the object is achieved providing a method according to claim 1.
  • the invention furthermore provides a downhole pump according to claim 8, and a pump assembly according to claim 10.
  • a method for pumping a wellbore liquid through a wellbore according to the claimed invention comprises:
  • a pump tubular in the wellbore tubular, such that the pump tubular and the wellbore tubular define an annular volume between the pump tubular and a wellbore tubular
  • the pump tubular comprises an interior space that extends between an inlet end of the pump tubular and an outlet end of the pump tubular, wherein a one-way inlet valve is provided in the interior space of the pump tubular, wherein a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve, and wherein the inlet valve and the outlet valve between them define a pump chamber in the interior space;
  • Providing a method according to the invention allows for efficiently pumping wellbore liquid through a wellbore, using a wellbore pump having a simplified pump design. Furthermore, the method allows for a pump tubular that is corrosive resistant and that protects the wellbore tubular, or at least a section thereof, to the corrosive properties of the wellbore liquid.
  • the pump tubular in particular along the actuator volume, shields the wellbore tubular, or casing, from the wellbore liquids. This is beneficial because wellbore tubulars are typically made of steel, and are susceptible to corrosive properties of wellbore liquids.
  • the invention allows for a pump of a simple design, and with a minimal number of components exposed to the wellbore liquid.
  • the main components of the downhole pump exposed to the wellbore liquid are an inside surface of the pump tubular, and the one-way valves.
  • the pump tubular extends along at least a section of wellbore tubular located below the pump chamber or pump chambers, preferably extends along the entire length of the wellbore tubular.
  • the pump tubular functions as a liner of the wellbore tubular.
  • the invention relates to a method for pumping liquid through a wellbore, using a pump tubular.
  • An actuator liquid is used to compress the pump tubular from the outside, and thus pump well bore liquid through the pump tubular.
  • the pump tubular comprises a an inner space with two one-way valves, the one way valve defining a pump chamber between them.
  • the pump tubular is mounted in a wellbore tubular, such that an annular volume is provided between the wellbore tubular and the pump tubular.
  • the pump tubular is adapted for use with low frequency pulses, for example pulses having a frequency in the range of 0.3 Hz to 3 Hz, for example pulses having a frequency of 0,5 Hz, 1 Hz or 2H z.
  • the pump chamber has a length of at least 500 meters, for example has a length in the range of 600-900 meters, preferably has a length in the range of 700 to 800 m, for example has a length of 750 meters.
  • Such a large length allows for the pump tubular to be made of a comparatively stiff material, while still being able to be compressed by an outside pressure, and thus to function as a pump.
  • the pump tubular can be substantially self-supporting, can be of a robust material, which can be handled and which can sustain harsh environments
  • the pump tubular is adapted for use with a particular actuator liquid, preferably in combination with low frequency pulses, and the length of the pump chamber corresponds with half the wavelength of a pulse, preferably a low frequency pulse, generated by the pulse generator in the particular actuator liquid.
  • the length of the actuator volume is adapted for use with a particular actuator liquid, and the length of actuator volume corresponds with half the wavelength of a pulse, preferably a low frequency pulse, generated by the pulse generator in the particular actuator liquid.
  • the length of the actuator volume is adapted for use with a particular actuator liquid, and the length of actuator volume corresponds with half the wavelength or to a half and/or an additional integer number of wavelengths, of a pulse generated by the pulse generator in the particular actuator liquid.
  • the generator allows for the generator to generate a pulses creating an interfering wave pattern, i.e. a standing wave in the actuator volume.
  • the outlet valve is located such and/or the wave generator is configured such that a node of the standing wave is located at or near the outlet valve.
  • the pump chamber is a first pump chamber
  • the pump tubular comprises a second pump chamber, the second pump chamber being located above and adjacent to the first pump chamber.
  • the second pump chamber at least has an inlet valve.
  • the outlet valve of the first pump chamber is the inlet valve of the second pump chamber.
  • the second pump chamber also has an outlet valve, which outlet valve is located above the inlet valve of the second pump chamber.
  • the three one-way valves i.e. the inlet valve of the first pump chamber, the outlet valve of the first pump chamber, which also is the inlet valve of the second pump chamber, and the outlet valve of the second pump chamber, are located at regular intervals.
  • the actuator volume is also adapted for use with the particular actuator liquid, and the length of actuator volume corresponds to the wavelength of a pulse generated by the pulse generator in the particular actuator liquid.
  • the pulse generator preferably is configured to generate a pulse at a frequency at which the pulse in the actuator liquid has a wave length that corresponds to the combined length of the first and second pump chamber.
  • the inlet valve of the first pump chamber, the outlet valve of the first pump chamber, which preferably also is the inlet valve of the second pump chamber, and the outlet valve of the second pump chamber are located at the nodes of the standing wave generated in the actuator volume.
  • a standing wave is generated in the actuator liquid in the actuator volume, and one way vales are provided in the pump tubular level with the nodes of said standing wave, such that the anti-nodes of the standing wave alternatingly compress and decompress the pump chamber between two one way valves.
  • This principle can be embodied with a standing wave of one wave length, or of multiple wave lengths.
  • the inlet valve of the first pump chamber is located near or at the bottom seal, which bottom seal is located in the annuls between the pump tubular and the wellbore tubular.
  • the outlet valve of the first pump chamber, or, if present, the outlet valve of the second pump chamber is located near or at the top end of the wellbore tubular.
  • the actuator volume is, at a top end thereof, delimited by a top seal.
  • the top seal is a moveable seal, and is part of the pulse generator for generating a pulse in actuator liquid held in the actuator volume.
  • the pump tubular is configured to be used with water, or a similar, as an actuator liquid.
  • the pump tubular is a reinforce plastic tubular, for example an Alkiet material tubular.
  • Plastics are, compared to for example metal well casing, well suited for use with corrosive wellbore liquids.
  • the well tubular is also a liner for the wellbore, protecting the wellbore tubular along at least part thereof, preferably along its entire length, from contact with the wellbore liquid.
  • the pump tubular comprises a pump chamber and the pump tubular is mounted in the wellbore tubular and/or the inlet valve of the pump chamber is mounted in the pump tubular, such that the distance between the top end of the wellbore tubular and the inlet valve is in the range of 400-1600 meters, for example is in the range of 600-1600 meters for example is in the range 1400-1600 meters, for example is located at about 1500 meters.
  • the pump tubular comprises a first pump chamber and a second pump chamber
  • the pump tubular is mounted in the wellbore tubular and/or the inlet valve of the first pump chamber is mounted in the pump tubular, such that the distance between the top end of the wellbore tubular and the inlet valve is in the range of 1200-1600 meters, for example is in the range of 1400 and 1600 meters, for example is located at about 1500 meters.
  • the pulse generator is a pulse pump.
  • the pulse generator is configured to periodically generate pulses, wherein the wave length of said pulses preferably are dimensioned such that a standing wave is created in the actuator liquid in the actuator volume.
  • the wave length of the pulse preferably is similar to two times the length of a pump chamber provided in the pump tubular. This is in particular beneficial when the pump tubular comprises two adjacent pump chambers, and the standing wave in the actuator volume is positioned relative to the two pump chambers such that one half of the standing wave compresses a section of the pump tubular defining a first pump chamber from an initial state into a compressed state, while at the same time the opposite half of the standing wave allows for the other pump chamber to expand from it compressed state into its initial state.
  • a peristaltic pumping motions generated in the two adjacent pump chambers is generated in the two adjacent pump chambers.
  • the pump tubular comprises a first and a second pump chamber and the pump tubular and the actuator volume are configured to enable the pulse generator to provide a low frequency pulse in the actuator liquid and thus bring about a peristaltic pumping motion in pump chambers of the pump tubular.
  • the pulse generator is an isobaric expansion engine.
  • Providing the pulse generator in the form of a isobaric expansion engine is in particular beneficial when the wellbore is used to pump up (or to pump down) warm water as a wellbore liquid, for example for use as geothermal energy.
  • heat of the wellbore liquid i.e. warm water, is used to drive the isobaric expansion engine.
  • isobaric expansion engines are known form the prior art. The working of these type of expansion engines is therefore not elaborated upon in this document.
  • the wellbore tubular comprise wellbore casing.
  • Wellbore casing typically is made out of metal tubulars.
  • the wellbore comprises a combination of wellbore tubulars of different diameter.
  • the first 1500 meter section of the wellbore tubular consists of wellbores having a first diameter, for example has a diameter of 40 cm, while a second section, located below the first section of the wellbore, consists of wellbores having a second diameter, wherein the second diameter is smaller than the first diameter.
  • the bottom seal is located in the first section of the wellbore tubular, preferably at or near the end of the first section.
  • the bottom seal is a packer.
  • the packer provides a fluid tight seal between the pump tubular and the wellbore casing, and thus provides the annular volume between the pump tubular and the wellbore casing. Furthermore, the packer preferably fixates the pump tubular in the wellbore casing, and positions the pump tubular concentric in the wellbore tubular.
  • the pump tubular comprises multiple one-way valves mounted inside the pump tubular, wherein the one-way valves are mounted inside the pump tubular at regular intervals, for example at intervals of 500m or of 750m, and subdivide the inner volume of the pump tubular into a string of similar sized pump chambers, each pump chamber extending between two one-way valves.
  • the pump tubular comprise two or more pump chambers.
  • a pump tubular is combined with an actuator volume, actuator liquid and a pulse generator, configured to periodically generate pulse at a low frequency, e.g. a frequency in the range of 0,5-2 Hz, the pulse having a wave length corresponding to the length of two pump chambers.
  • a pulse generator configured to periodically generate pulse at a low frequency, e.g. a frequency in the range of 0,5-2 Hz, the pulse having a wave length corresponding to the length of two pump chambers.
  • a spacer is provided in the actuator volume, preferably at or near the one way valve between the first pump chamber and the second pump chamber, to positon the pump tubular substantially concentric in the wellbore tubular.
  • the spacer is configured to position the pump tubular in the wellbore tubular, and to allow actuator liquid to flow through the actuator volume and along or through the spacer.
  • the pump tubular is elastic, at least along parts of the pump tubular that extend along the pump chambers, to enable the pump chambers to be compressed and decompressed in a substantially radial direction by increasing and decreasing pressure in the annular volume adjacent the pump chamber.
  • the pump tubular has an e-modulus in the range of 18.000 Mpa - 24.000 Mpa, preferably in the range of 20.000 Mpa - 22.000 Mpa, for example 21.000 Mpa.
  • the pump tubular having an outside diameter in the range of 200 mm - 3000 mm, preferably in the range of 220 mm - 260 mm, and a wall thickness in the range of 6 mm - 16 mm, preferably in the range of 9 mm - 13 mm.
  • the pump tubular has similar material properties along its length, for example is a tubular out of composite material, for example a tubular composed out of smaller tubular sections which tubular sections have been connected to each other at their ends, for example are glued to each other or a screwed into one another.
  • the pump tubular below the inlet valve of the pump chamber, comprises a dip tubular, which dip tubular preferably is an extension of the pump tubular, the dip tubular having a diameter and a wall thickness similar to the diameter and wall thickness of the pump tubular above the inlet valve of the pump chamber.
  • the dip tubular provides a conduit between the pump tubular, more in particular a pump chamber of the pump tubular, and a bottom area of the wellbore.
  • the downhole pump does not utilise the wellbore tubular, i.e. the casing of the wellbore, to provide the actuator volume, but comprises an actuator volume tubular, extending along the outside of the pump tubular.
  • the actuator volume is comprised between the pump tubular and the actuator volume tubular.
  • the actuator volume tubular may comprise multiple tubular sections combined into a string of tubulars.
  • the actuator volume preferably is more rigid than the pump tubular to prevent the actuator volume tubular from deforming under the pressure of the standing wave generated in the actuator volume during use.
  • the actuator volume tubular may in use be supported by a liquid provided in the annular space between the actuator volume tubular and the wellbore tubular.
  • Fig. 1 shows a schematic view in cross section of a downhole pump
  • Fig. 2 shows a schematic view in cross section of another downhole pump
  • Figure 1 shows a schematic view in cross section of a wellbore 1 provided with a downhole pump 2 according to the invention.
  • the downhole pump 1 comprises a wellbore tubular 3, a pump tubular 4, a bottom seal 5 and a pulse generator 6.
  • the wellbore tubular 3 is mounted in the wellbore 1.
  • the wellbore tubular comprises casing tubular of different diameters. Casing having a first, wider, diameter is used for the upper part of the wellbore tubular, while casing having a more narrow diameter is used for the lower section of the wellbore. This stepwise narrowing is typical for wellbore casing.
  • the pump tubular 4 is mounted in the wellbore tubular 3.
  • the pump tubular 4 is supported at its top end 7, end extends way down such that its bottom end 8 is located at the bottom 11 of the wellbore 1.
  • the pump tubular 4 is mounted in the wellbore tubular 3 such that the pump tubular 4 and the wellbore tubular 3 define an annular volume 12 between the pump tubular and a wellbore tubular.
  • the pump tubular 4 comprises an interior space 13 that extends between an inlet end 14, in the embodiment shown the bottom end 8, of the pump tubular and an outlet end 15, in the embodiment shown the top end 7, of the pump tubular.
  • the pump tubular is provided with two one-way valves, a one-way inlet valve 16 and a one-way outlet valve 17.
  • the inlet and outlet valve are provided in the interior space 13 of the pump tubular 4.
  • the one-way outlet valve 17 is provided above the one-way inlet valve 16.
  • the inlet valve 16 and the outlet valve 17 between them define a pump chamber 18 in the interior space 13.
  • a third one way valve 19 is provided in the interior space 13 of the pump tubular 4.
  • the third one-way valve 19 in combination with the one way outlet valve of the pump chamber 18, defines a second pump chamber 20.
  • the pump chamber 18 is a first pump chamber
  • the pump tubular comprises a second pump chamber 20, the second pump chamber being located above and adjacent to the first pump chamber.
  • the outlet valve 17 of the first pump chamber 18 is the inlet valve of the second pump chamber 20.
  • the third one-way valve 19 is the outlet valve of the second pump chamber 20, and is located above the inlet valve 17 of the second pump chamber.
  • the three one-way valves i.e. the inlet valve 16 of the first pump chamber 18, the outlet valve 17 of the first pump chamber 18, which outlet valve also is the inlet valve of the second pump chamber 20, and the outlet valve 19 of the second pump chamber 20, are located at regular intervals.
  • the bottom seal 5 is mounted between the wellbore tubular 3 and the pump tubular 4 to enable the annular volume 12 to hold an actuator liquid above the seal.
  • the wellbore tubular 3, the pump tubular 4 and the bottom seal 5 define an annular actuator volume 21.
  • the annular actuator volume 21 is a section of the annular volume for holding actuator liquid to actuate the pump tubular 4, more in particular the pump chambers 18,20 of the pump tubular.
  • the pulse generator 22 is configured to periodically generate a pulse in an actuator liquid in the actuator volume 21.
  • the generated pulse forms a pressure wave in the actuator liquid, which compresses the pump tubular 4, and therefore the pump chambers 18, 20, to thus urge well bore liquid from the pump chamber through the outlet valve.
  • the section of the pump tubular comprising the first and second pump chamber has a length of about 1500 m.
  • the bottom seal is mounted near the inlet valve 16 of the first pump chamber, such that the annular actuator volume has a length that corresponds to two the length of the section of the pump tubular comprising the first and the second pump chamber.
  • the pump tubular extends below the lowest pump chamber further down the bore hole.
  • This lower section of the pump tubular corresponds with the more narrow section of the wellbore casing. It is submitted that, to enable the actuator volume to hold sufficient actuator liquid for compressing the pump tubular, and at the same time allow for the pump tubular to have an inner diameter that allows for the one or more pump chambers to hold a significant volume of wellbore liquid, the active part of the pump tubular, i.e. the part comprising the one or more pump chambers, is located in the upper section of the wellbore tubular, this upper section typically having a wider diameter than the lower section of the wellbore tubular.
  • the method and downhole pump according to the claimed invention also allow for a pump tubular having a single pump chamber, or for a second pump chamber above the first pump chamber, wherein the second pump chamber is not provided with a one way valve at the top end.
  • the flow of wellbore liquid is generated by periodically compressing the pump chamber.
  • the invention furthermore allows for three or more pump chambers, preferably located one above the other and having similar lengths. Such an embodiment may be useful in pumps having a great depth.
  • the pulse generator 6 preferably is configured to generate a pulse that alternatingly compresses adjacent pump chambers, in the embodiment shown alternatingly compresses the upper pump chamber 20 and the lower pump chamber 18, and thus creates for a peristaltic pump movement.
  • the method and down hole pump according to the invention can be used for pumping wellbore liquid into a wellbore and for pumping wellbore liquid out of a wellbore by adapting the direction in which the one-way valves allow wellbore liquid to pass.
  • the one-way valves are configured such that they allow wellbore liquid to pass the valves upward.
  • the pump tubular is configured to pump wellbore liquid out of the wellbore.
  • the pump tubular can be configured to pump wellbore liquid into the wellbore
  • the downhole pump 2 shown in Figure 1 allows for a method according to the claimed invention, i.e. a method for pumping a wellbore liquid through a wellbore, the method comprising: periodically generating a pulse in the actuator liquid located in the actuator volume 21 with the pulse generator 6, the pulse compressing the pump tubular 4 and therefore the pump chamber, in the embodiment shown the pump chambers 18, 20, to thus urge well bore liquid from the pump chamber through the outlet valve of the respective pump chamber.
  • the pump tubular 4 comprises an interior space 13 that extends between an inlet end14 of the pump tubular 4 and an outlet end 15 of the pump tubular 4, wherein a one-way inlet valve 16 is provided in the interior space 13 of the pump tubular 4, wherein a one-way outlet valve 17 is provided in the interior space 13 of the pump tubular 4 and above the inlet valve 16, and wherein the inlet valve 16 and the outlet valve 17 between them define a pump chamber 18 in the interior space 13;
  • a pulse generator 6 which pulse generator is configured to periodically generate a pulse in an actuator liquid 22 in the actuator volume 21 ;
  • the actuator volume is adapted for use with the particular actuator liquid, e.g. water, and the length of actuator volume corresponds to the wavelength of a low frequency pulse generated by the pulse generator in the particular actuator liquid.
  • the pulse generator is configured to generate a pulse at a frequency at which the pulse in the actuator liquid has a wave length that corresponds to the combined length of the first and second pump chamber.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)

Abstract

This invention relates to a downhole pump and a method for pumping liquid through a wellbore. The method comprises mounting a wellbore tubular into the wellbore, a pump tubular into the wellbore tubular, a bottom seal between the wellbore tubular and the pump tubular, and a pulse generator to periodically generate a pulse in an actuator liquid. The wellbore tubular, pump tubular and the bottom seal define an annular actuator volume which contains the actuator liquid. A one-way inlet valve is provided in theinterior space of the pump tubular and a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve. The inlet valve and the outlet valve between them define a pump chamber. The periodically generated pulse compresses the pump tubular and thus urges well bore liquid from the pump chamber through the outlet valve pumping liquid through the wellbore.

Description

Title: Method and downhole pump for pumping liquid through a wellbore
FIELD AND BACKGROUND OF THE INVENTION
This invention relates to a downhole pump and a method for pumping liquid through a wellbore.
The invention in particular relates to a unique method and a downhole pump of unique features to pump wellbore liquids, e.g. hydrocarbons or water from subsurface reservoirs communicating with the earth’s surface by way of a wellbore.
Furthermore, the method and the downhole pump according to the claimed invention can be configured to pump well bore liquids through a wellbore out of a subsurface reservoir, and can be configured to pump well bore liquids through a wellbore into a subsurface reservoir.
Very few of the wells completed flow free of their own accord. Approximately 90% require some means of artificial lifting system to bring the wanted wellbore liquids such as
hydrocarbons to the surface. The method and equipment chosen depend upon the depth of the well and of course the cost involved.
A typical method of bringing liquids to the surface is by means of an electrically powered submersible pump. The pump, together with its driving motor, is lowered down the wellbore to the bottom of the well. Power is transmitted through an electrical cable from a surface control box. The pressure created by the pump then forces the wellbore liquid to the surface.
In the wellbore, the pump, in particular those components of the pump that are in direct contact with the wellbore liquids, is subject to the aggressive, in particular corrosive, character of the wellbore liquid and to high temperatures.
Furthermore, to provide access to the well, for example for maintenance or inspection, the pump has to be lifted from the well and the cables have to be removed.
A further problem is that pumps are often relatively bulky and there are occasions when they cannot be placed where they are most needed. In such cases the pump may have to be situated in a less convenient location in which case liquid to be moved has to be piped to and from the pump and this can introduce other difficulties. The present invention is directed to a pump which not only reduces the disadvantages of many existing pumps but in addition provides other important advantages.
It is an object of the invention to provide an alternative downhole pump and/or method, for pumping a wellbore liquid through a well bore. It is a further object of the invention to obviate, or at least reduce, one or more of the problems described hereinabove and in particular to provide a less complicated and less expensive method and/or downhole pump for lifting wellbore liquids from subsurface reservoirs. It is a further object of the invention to provide a pump that is able to withstand corrosion from wellbore fluids to a great extent.
SUMMARY OF THE INVENTION
According to the present invention, the object is achieved providing a method according to claim 1. The invention furthermore provides a downhole pump according to claim 8, and a pump assembly according to claim 10.
A method for pumping a wellbore liquid through a wellbore according to the claimed invention comprises:
- mounting a wellbore tubular in the wellbore;
- mounting a pump tubular in the wellbore tubular, such that the pump tubular and the wellbore tubular define an annular volume between the pump tubular and a wellbore tubular, wherein the pump tubular comprises an interior space that extends between an inlet end of the pump tubular and an outlet end of the pump tubular, wherein a one-way inlet valve is provided in the interior space of the pump tubular, wherein a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve, and wherein the inlet valve and the outlet valve between them define a pump chamber in the interior space;
- mounting a bottom seal between the wellbore tubular and the pump tubular to enable the annular volume to hold an actuator liquid above the bottom seal; wherein the wellbore tubular, the pump tubular and the bottom seal define an annular actuator volume;
- mounting a pulse generator, which pulse generator is configured to periodically generate a pulse in an actuator liquid in the actuator volume;
- filling the actuator volume with an actuator liquid,
- periodically generating a pulse in the actuator liquid with the pulse generator, the pulse compressing the pump tubular and therefore the pump chamber to thus urge well bore liquid from the pump chamber through the outlet valve.
Providing a method according to the invention allows for efficiently pumping wellbore liquid through a wellbore, using a wellbore pump having a simplified pump design. Furthermore, the method allows for a pump tubular that is corrosive resistant and that protects the wellbore tubular, or at least a section thereof, to the corrosive properties of the wellbore liquid.
The pump tubular, in particular along the actuator volume, shields the wellbore tubular, or casing, from the wellbore liquids. This is beneficial because wellbore tubulars are typically made of steel, and are susceptible to corrosive properties of wellbore liquids.
Furthermore, the invention allows for a pump of a simple design, and with a minimal number of components exposed to the wellbore liquid. The main components of the downhole pump exposed to the wellbore liquid are an inside surface of the pump tubular, and the one-way valves.
In a further embodiment, the pump tubular extends along at least a section of wellbore tubular located below the pump chamber or pump chambers, preferably extends along the entire length of the wellbore tubular. Thus the well bore casing, or at least a significant part thereof, is shielded from the wellbore liquids. In such an embodiment, the pump tubular functions as a liner of the wellbore tubular.
The invention relates to a method for pumping liquid through a wellbore, using a pump tubular. An actuator liquid is used to compress the pump tubular from the outside, and thus pump well bore liquid through the pump tubular. In an embodiment, the pump tubular comprises a an inner space with two one-way valves, the one way valve defining a pump chamber between them. The pump tubular is mounted in a wellbore tubular, such that an annular volume is provided between the wellbore tubular and the pump tubular.
In this annular volume are mounted a bottom seal and a top seal, that define between them a actuator volume alongside the pump chamber.
In an embodiment, the pump tubular is adapted for use with low frequency pulses, for example pulses having a frequency in the range of 0.3 Hz to 3 Hz, for example pulses having a frequency of 0,5 Hz, 1 Hz or 2H z.
In an embodiment, the pump chamber has a length of at least 500 meters, for example has a length in the range of 600-900 meters, preferably has a length in the range of 700 to 800 m, for example has a length of 750 meters.
Such a large length allows for the pump tubular to be made of a comparatively stiff material, while still being able to be compressed by an outside pressure, and thus to function as a pump.
Thus, the pump tubular can be substantially self-supporting, can be of a robust material, which can be handled and which can sustain harsh environments
In an embodiment, the pump tubular is adapted for use with a particular actuator liquid, preferably in combination with low frequency pulses, and the length of the pump chamber corresponds with half the wavelength of a pulse, preferably a low frequency pulse, generated by the pulse generator in the particular actuator liquid.
In an embodiment, the length of the actuator volume is adapted for use with a particular actuator liquid, and the length of actuator volume corresponds with half the wavelength of a pulse, preferably a low frequency pulse, generated by the pulse generator in the particular actuator liquid.
In an embodiment, the length of the actuator volume is adapted for use with a particular actuator liquid, and the length of actuator volume corresponds with half the wavelength or to a half and/or an additional integer number of wavelengths, of a pulse generated by the pulse generator in the particular actuator liquid. Such an embodiment allows for the generator to generate a pulses creating an interfering wave pattern, i.e. a standing wave in the actuator volume. In such an embodiment, preferably the outlet valve is located such and/or the wave generator is configured such that a node of the standing wave is located at or near the outlet valve.
In an embodiment, the pump chamber is a first pump chamber, and the pump tubular comprises a second pump chamber, the second pump chamber being located above and adjacent to the first pump chamber.
In such an embodiment, the second pump chamber at least has an inlet valve. Preferably, the outlet valve of the first pump chamber is the inlet valve of the second pump chamber.
In a further embodiment, the second pump chamber also has an outlet valve, which outlet valve is located above the inlet valve of the second pump chamber.
Preferably, the three one-way valves, i.e. the inlet valve of the first pump chamber, the outlet valve of the first pump chamber, which also is the inlet valve of the second pump chamber, and the outlet valve of the second pump chamber, are located at regular intervals.
In a further embodiment, the actuator volume is also adapted for use with the particular actuator liquid, and the length of actuator volume corresponds to the wavelength of a pulse generated by the pulse generator in the particular actuator liquid.
In such an embodiment, the pulse generator preferably is configured to generate a pulse at a frequency at which the pulse in the actuator liquid has a wave length that corresponds to the combined length of the first and second pump chamber. Thus, the inlet valve of the first pump chamber, the outlet valve of the first pump chamber, which preferably also is the inlet valve of the second pump chamber, and the outlet valve of the second pump chamber, are located at the nodes of the standing wave generated in the actuator volume.
It is submitted that in a preferred embodiment according to the invention, a standing wave is generated in the actuator liquid in the actuator volume, and one way vales are provided in the pump tubular level with the nodes of said standing wave, such that the anti-nodes of the standing wave alternatingly compress and decompress the pump chamber between two one way valves. This principle can be embodied with a standing wave of one wave length, or of multiple wave lengths.
In an embodiment, the inlet valve of the first pump chamber is located near or at the bottom seal, which bottom seal is located in the annuls between the pump tubular and the wellbore tubular. In an embodiment, the outlet valve of the first pump chamber, or, if present, the outlet valve of the second pump chamber, is located near or at the top end of the wellbore tubular.
In an embodiment, the actuator volume is, at a top end thereof, delimited by a top seal. In a further embodiment, the top seal is a moveable seal, and is part of the pulse generator for generating a pulse in actuator liquid held in the actuator volume.
In an embodiment the pump tubular is configured to be used with water, or a similar, as an actuator liquid.
In an embodiment, the pump tubular is a reinforce plastic tubular, for example an Alkiet material tubular. Plastics are, compared to for example metal well casing, well suited for use with corrosive wellbore liquids.
In an embodiment, the well tubular is also a liner for the wellbore, protecting the wellbore tubular along at least part thereof, preferably along its entire length, from contact with the wellbore liquid.
In an embodiment, the pump tubular comprises a pump chamber and the pump tubular is mounted in the wellbore tubular and/or the inlet valve of the pump chamber is mounted in the pump tubular, such that the distance between the top end of the wellbore tubular and the inlet valve is in the range of 400-1600 meters, for example is in the range of 600-1600 meters for example is in the range 1400-1600 meters, for example is located at about 1500 meters.
In an embodiment, the pump tubular comprises a first pump chamber and a second pump chamber, and the pump tubular is mounted in the wellbore tubular and/or the inlet valve of the first pump chamber is mounted in the pump tubular, such that the distance between the top end of the wellbore tubular and the inlet valve is in the range of 1200-1600 meters, for example is in the range of 1400 and 1600 meters, for example is located at about 1500 meters.
In an embodiment, the pulse generator is a pulse pump. The pulse generator is configured to periodically generate pulses, wherein the wave length of said pulses preferably are dimensioned such that a standing wave is created in the actuator liquid in the actuator volume.
The wave length of the pulse preferably is similar to two times the length of a pump chamber provided in the pump tubular. This is in particular beneficial when the pump tubular comprises two adjacent pump chambers, and the standing wave in the actuator volume is positioned relative to the two pump chambers such that one half of the standing wave compresses a section of the pump tubular defining a first pump chamber from an initial state into a compressed state, while at the same time the opposite half of the standing wave allows for the other pump chamber to expand from it compressed state into its initial state. Thus a peristaltic pumping motions generated in the two adjacent pump chambers.
In an embodiment, the pump tubular comprises a first and a second pump chamber and the pump tubular and the actuator volume are configured to enable the pulse generator to provide a low frequency pulse in the actuator liquid and thus bring about a peristaltic pumping motion in pump chambers of the pump tubular.
In an embodiment, the pulse generator is an isobaric expansion engine. Providing the pulse generator in the form of a isobaric expansion engine is in particular beneficial when the wellbore is used to pump up (or to pump down) warm water as a wellbore liquid, for example for use as geothermal energy. In such an embodiment, heat of the wellbore liquid, i.e. warm water, is used to drive the isobaric expansion engine.
In this context it is noted that isobaric expansion engines are known form the prior art. The working of these type of expansion engines is therefore not elaborated upon in this document.
In an embodiment, the wellbore tubular comprise wellbore casing. Wellbore casing typically is made out of metal tubulars. In an embodiment, the wellbore comprises a combination of wellbore tubulars of different diameter. For example, the first 1500 meter section of the wellbore tubular consists of wellbores having a first diameter, for example has a diameter of 40 cm, while a second section, located below the first section of the wellbore, consists of wellbores having a second diameter, wherein the second diameter is smaller than the first diameter.
In such an embodiment, the bottom seal is located in the first section of the wellbore tubular, preferably at or near the end of the first section.
In an embodiment, the bottom seal is a packer.
Preferably, the packer provides a fluid tight seal between the pump tubular and the wellbore casing, and thus provides the annular volume between the pump tubular and the wellbore casing. Furthermore, the packer preferably fixates the pump tubular in the wellbore casing, and positions the pump tubular concentric in the wellbore tubular. In an embodiment, the pump tubular comprises multiple one-way valves mounted inside the pump tubular, wherein the one-way valves are mounted inside the pump tubular at regular intervals, for example at intervals of 500m or of 750m, and subdivide the inner volume of the pump tubular into a string of similar sized pump chambers, each pump chamber extending between two one-way valves.
In such an embodiment, the pump tubular comprise two or more pump chambers. Preferably such a pump tubular is combined with an actuator volume, actuator liquid and a pulse generator, configured to periodically generate pulse at a low frequency, e.g. a frequency in the range of 0,5-2 Hz, the pulse having a wave length corresponding to the length of two pump chambers. Such an embodiment allows for generating pulses having a wave length that cause one or more standing waves, the nodes of the standing waves being located at or near the valves of the string of pump chambers.
In an embodiment, a spacer is provided in the actuator volume, preferably at or near the one way valve between the first pump chamber and the second pump chamber, to positon the pump tubular substantially concentric in the wellbore tubular. The spacer is configured to position the pump tubular in the wellbore tubular, and to allow actuator liquid to flow through the actuator volume and along or through the spacer.
In an embodiment, the pump tubular is elastic, at least along parts of the pump tubular that extend along the pump chambers, to enable the pump chambers to be compressed and decompressed in a substantially radial direction by increasing and decreasing pressure in the annular volume adjacent the pump chamber.
In an embodiment, the pump tubular has an e-modulus in the range of 18.000 Mpa - 24.000 Mpa, preferably in the range of 20.000 Mpa - 22.000 Mpa, for example 21.000 Mpa.
Preferably in combination with the pump tubular having an outside diameter in the range of 200 mm - 3000 mm, preferably in the range of 220 mm - 260 mm, and a wall thickness in the range of 6 mm - 16 mm, preferably in the range of 9 mm - 13 mm.
In an embodiment, the pump tubular has similar material properties along its length, for example is a tubular out of composite material, for example a tubular composed out of smaller tubular sections which tubular sections have been connected to each other at their ends, for example are glued to each other or a screwed into one another.
In an embodiment, the pump tubular, below the inlet valve of the pump chamber, comprises a dip tubular, which dip tubular preferably is an extension of the pump tubular, the dip tubular having a diameter and a wall thickness similar to the diameter and wall thickness of the pump tubular above the inlet valve of the pump chamber. The dip tubular provides a conduit between the pump tubular, more in particular a pump chamber of the pump tubular, and a bottom area of the wellbore. Providing the pump tubular with a dip tubular is in particular beneficial when the wellbore extends significantly below the pump tubular, and especially when wellbore liquid surface level in the well bore is located below the inlet valve of the pump tubular.
It is submitted that in an alternative embodiment, the downhole pump does not utilise the wellbore tubular, i.e. the casing of the wellbore, to provide the actuator volume, but comprises an actuator volume tubular, extending along the outside of the pump tubular. In such an embodiment, the actuator volume is comprised between the pump tubular and the actuator volume tubular. Like the pump tubular, the actuator volume tubular may comprise multiple tubular sections combined into a string of tubulars. The actuator volume preferably is more rigid than the pump tubular to prevent the actuator volume tubular from deforming under the pressure of the standing wave generated in the actuator volume during use. In a further embodiment, the actuator volume tubular may in use be supported by a liquid provided in the annular space between the actuator volume tubular and the wellbore tubular.
Advantageous embodiments of the method according to the invention and the assembly according to the invention are disclosed in the sub claims and in the description, in which the invention is further illustrated and elucidated on the basis of a number of exemplary embodiments, of which some are shown in the schematic drawing. In the figures, components corresponding in terms or construction and/or function are provided with the same last two digits of the reference numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a schematic view in cross section of a downhole pump; and
Fig. 2 shows a schematic view in cross section of another downhole pump;
DETAILED DESCRIPTION
Figure 1 shows a schematic view in cross section of a wellbore 1 provided with a downhole pump 2 according to the invention.
The downhole pump 1 comprises a wellbore tubular 3, a pump tubular 4, a bottom seal 5 and a pulse generator 6. The wellbore tubular 3 is mounted in the wellbore 1. In the embodiment shown, the wellbore tubular comprises casing tubular of different diameters. Casing having a first, wider, diameter is used for the upper part of the wellbore tubular, while casing having a more narrow diameter is used for the lower section of the wellbore. This stepwise narrowing is typical for wellbore casing.
The pump tubular 4 is mounted in the wellbore tubular 3. In the embodiment shown, the pump tubular 4 is supported at its top end 7, end extends way down such that its bottom end 8 is located at the bottom 11 of the wellbore 1.
The pump tubular 4 is mounted in the wellbore tubular 3 such that the pump tubular 4 and the wellbore tubular 3 define an annular volume 12 between the pump tubular and a wellbore tubular.
The pump tubular 4 comprises an interior space 13 that extends between an inlet end 14, in the embodiment shown the bottom end 8, of the pump tubular and an outlet end 15, in the embodiment shown the top end 7, of the pump tubular.
According to the invention, the pump tubular is provided with two one-way valves, a one-way inlet valve 16 and a one-way outlet valve 17. The inlet and outlet valve are provided in the interior space 13 of the pump tubular 4.
The one-way outlet valve 17 is provided above the one-way inlet valve 16. The inlet valve 16 and the outlet valve 17 between them define a pump chamber 18 in the interior space 13.
In the particular embodiment shown, a third one way valve 19 is provided in the interior space 13 of the pump tubular 4. The third one-way valve 19 in combination with the one way outlet valve of the pump chamber 18, defines a second pump chamber 20.
Thus, in the embodiment shown, the pump chamber 18 is a first pump chamber, and the pump tubular comprises a second pump chamber 20, the second pump chamber being located above and adjacent to the first pump chamber.
In the embodiment shown, the outlet valve 17 of the first pump chamber 18 is the inlet valve of the second pump chamber 20. The third one-way valve 19 is the outlet valve of the second pump chamber 20, and is located above the inlet valve 17 of the second pump chamber. In the embodiment shown, the three one-way valves, i.e. the inlet valve 16 of the first pump chamber 18, the outlet valve 17 of the first pump chamber 18, which outlet valve also is the inlet valve of the second pump chamber 20, and the outlet valve 19 of the second pump chamber 20, are located at regular intervals.
The bottom seal 5 is mounted between the wellbore tubular 3 and the pump tubular 4 to enable the annular volume 12 to hold an actuator liquid above the seal. Thus, the wellbore tubular 3, the pump tubular 4 and the bottom seal 5 define an annular actuator volume 21.
The annular actuator volume 21 is a section of the annular volume for holding actuator liquid to actuate the pump tubular 4, more in particular the pump chambers 18,20 of the pump tubular.
The pulse generator 22 is configured to periodically generate a pulse in an actuator liquid in the actuator volume 21. The generated pulse forms a pressure wave in the actuator liquid, which compresses the pump tubular 4, and therefore the pump chambers 18, 20, to thus urge well bore liquid from the pump chamber through the outlet valve.
In the embodiment shown, the section of the pump tubular comprising the first and second pump chamber has a length of about 1500 m. Furthermore, in the embodiment shown, the bottom seal is mounted near the inlet valve 16 of the first pump chamber, such that the annular actuator volume has a length that corresponds to two the length of the section of the pump tubular comprising the first and the second pump chamber.
In the embodiment shown, the pump tubular extends below the lowest pump chamber further down the bore hole. This lower section of the pump tubular corresponds with the more narrow section of the wellbore casing. It is submitted that, to enable the actuator volume to hold sufficient actuator liquid for compressing the pump tubular, and at the same time allow for the pump tubular to have an inner diameter that allows for the one or more pump chambers to hold a significant volume of wellbore liquid, the active part of the pump tubular, i.e. the part comprising the one or more pump chambers, is located in the upper section of the wellbore tubular, this upper section typically having a wider diameter than the lower section of the wellbore tubular.
It should be noted that the method and downhole pump according to the claimed invention also allow for a pump tubular having a single pump chamber, or for a second pump chamber above the first pump chamber, wherein the second pump chamber is not provided with a one way valve at the top end.
With a single pump chamber, the flow of wellbore liquid is generated by periodically compressing the pump chamber.
With the embodiment shown allows for alternatingly compressing the upper and the lower pump chamber, and thus allows for a peristaltic pump movement, as will be explained in more detail below.
The invention furthermore allows for three or more pump chambers, preferably located one above the other and having similar lengths. Such an embodiment may be useful in pumps having a great depth.
In an embodiment comprising two or more pump chambers, the pulse generator 6 preferably is configured to generate a pulse that alternatingly compresses adjacent pump chambers, in the embodiment shown alternatingly compresses the upper pump chamber 20 and the lower pump chamber 18, and thus creates for a peristaltic pump movement.
It should be noted that the method and down hole pump according to the invention can be used for pumping wellbore liquid into a wellbore and for pumping wellbore liquid out of a wellbore by adapting the direction in which the one-way valves allow wellbore liquid to pass.
In the embodiment shown, the one-way valves are configured such that they allow wellbore liquid to pass the valves upward. Thus, the pump tubular is configured to pump wellbore liquid out of the wellbore. By inverting the one-way valves, the pump tubular can be configured to pump wellbore liquid into the wellbore
The downhole pump 2 shown in Figure 1 allows for a method according to the claimed invention, i.e. a method for pumping a wellbore liquid through a wellbore, the method comprising: periodically generating a pulse in the actuator liquid located in the actuator volume 21 with the pulse generator 6, the pulse compressing the pump tubular 4 and therefore the pump chamber, in the embodiment shown the pump chambers 18, 20, to thus urge well bore liquid from the pump chamber through the outlet valve of the respective pump chamber.
In a more elaborate method according to the claimed invention comprises:
- mounting the wellbore tubular 3 in the wellbore 1 ; - mounting the pump tubular 4 in the wellbore tubular 3, such that the pump tubular 4 and the wellbore tubular 3 define an annular volume 12 between the pump tubular and a wellbore tubular, wherein the pump tubular 4 comprises an interior space 13 that extends between an inlet end14 of the pump tubular 4 and an outlet end 15 of the pump tubular 4, wherein a one-way inlet valve 16 is provided in the interior space 13 of the pump tubular 4, wherein a one-way outlet valve 17 is provided in the interior space 13 of the pump tubular 4 and above the inlet valve 16, and wherein the inlet valve 16 and the outlet valve 17 between them define a pump chamber 18 in the interior space 13;
- mounting a bottom seal 5 between the wellbore tubular 3 and the pump tubular 4 to enable the annular volume 12 to hold an actuator liquid 22 above the bottom seal 5; wherein the wellbore tubular 3, the pump tubular 4 and the bottom seal 5 define an annular actuator volume 21 ;
- mounting a pulse generator 6, which pulse generator is configured to periodically generate a pulse in an actuator liquid 22 in the actuator volume 21 ;
- filling the actuator volume 21 with actuator liquid 22, and
- periodically generating a pulse in the actuator liquid 22 with the pulse generator 6, the pulse compressing the pump tubular 4 and therefore the pump chamber 18 to thus urge well bore liquid 23 from the pump chamber 18 through the outlet valve 17.
In the embodiment shown in figure 1 , the actuator volume is adapted for use with the particular actuator liquid, e.g. water, and the length of actuator volume corresponds to the wavelength of a low frequency pulse generated by the pulse generator in the particular actuator liquid. In such an embodiment, the pulse generator is configured to generate a pulse at a frequency at which the pulse in the actuator liquid has a wave length that corresponds to the combined length of the first and second pump chamber. Reference signs
01 well bore
02 downhole pump
03 wellbore tubular
04 pump tubular
05 bottom seal
06 pulse generator
07 top end pump tubular
08 bottom end pump tubular
09 top section wellbore casing
10 bottom section wellbore casing
11 bottom wellbore
12 annular volume
13 interior space
14 inlet end pump tubular
15 outlet end
16 one way inlet valve
17 one way outlet valve
18 first pump chamber
19 third one way valve
20 second pump chamber
21 annular actuator volume
22 actuator liquid
23 wellbore liquid

Claims

1. Method for pumping a wellbore liquid through a wellbore, the method comprising:
- mounting a wellbore tubular in the wellbore;
- mounting a pump tubular in the wellbore tubular, such that the pump tubular and the wellbore tubular define an annular volume between the pump tubular and a wellbore tubular, wherein the pump tubular comprises an interior space that extends between an inlet end of the pump tubular and an outlet end of the pump tubular, wherein a one-way inlet valve is provided in the interior space of the pump tubular, wherein a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve, and wherein the inlet valve and the outlet valve between them define a pump chamber in the interior space;
- mounting a bottom seal between the wellbore tubular and the pump tubular to enable the annular volume to hold an actuator liquid above the bottom seal; wherein the wellbore tubular, the pump tubular and the bottom seal define an annular actuator volume;
- mounting a pulse generator, which pulse generator is configured to periodically generate a pulse in an actuator liquid in the actuator volume;
- filling the actuator volume with an actuator liquid,
- periodically generating a pulse in the actuator liquid with the pulse generator, the pulse compressing the pump tubular and therefore the pump chamber to thus urge well bore liquid from the pump chamber through the outlet valve.
2. Method according to clam 1 , wherein the pulse generator is used to generate pulses creating an interfering wave pattern, i.e. a standing wave in the actuator volume, which standing wave is dimensioned such that halve a wave length corresponds with the length of the pump chamber, and which standing wave is aligned with the pump chamber such that the pump chamber is compressed at the frequency at which the wave is generated.
3. Method according to clam 1 or claim 2, wherein the pump tubular comprises a first pump chamber and a second pump chamber, which second pump chamber preferably is located adjacent the first pump chamber, and wherein the pulse generator is used to provide a pulse in the actuator liquid creates a peristaltic pumping motion, i.e. that compresses the first pump while the second pump chamber expands, and vice versa.
4. Method according to claim 3, wherein the pulse generator is used to generate pulses creating an interfering wave pattern, i.e. a standing wave in the actuator volume, which standing wave is dimensioned such that a wave length corresponds with the combined length of the first pump chamber and the second pump chamber, and which standing wave is aligned with the pump chambers such that the pulse generator creates a peristaltic pumping motion.
5. Method according to one or more of the preceding claims, wherein the pulse generator generates low frequency pulses, for example pulses having a frequency in the range of 0.3 Hz to 3 Hz, for example pulses having a frequency of 0,5 Hz, 1 Hz or 2H z.
6. Method according to one or more of the preceding claims, wherein the actuator liquid is water, or a similar liquid.
7. Method according to one or more of the preceding claims, further comprising mounting the bottom seal at a depth in the wellbore of about 1500 meters, such that the actuator volume extends over a length of about 1500 meters.
8. Downhole pump for pumping a wellbore liquid through a wellbore, preferably a down hole pump for enabling a method according to one or more of the preceding claims, the downhole pump comprising;
- a wellbore tubular mounted in a wellbore;
- a pump tubular, mounted in the wellbore tubular such that the pump tubular and the wellbore tubular define an annular volume between the pump tubular and a wellbore tubular, wherein the pump tubular comprises an interior space that extends between an inlet end of the pump tubular and an outlet end of the pump tubular, wherein a one-way inlet valve is provided in the interior space of the pump tubular, wherein a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve, and wherein the inlet valve and the outlet valve between them define a pump chamber in the interior space;
- a bottom seal mounted between the wellbore tubular and the pump tubular to enable the annular volume to hold an actuator liquid above the bottom seal; wherein the wellbore tubular, the pump tubular and the bottom seal define an annular actuator volume;
- a pulse generator, which pulse generator is configured to periodically generate a pulse in an actuator liquid in the actuator volume, the pulse compressing the pump tubular and therefore the pump chamber to thus urge well bore liquid from the pump chamber through the outlet valve.
9. Downhole pump according to claim 8, wherein the length of the one or more pump chambers is at least 500 m, preferably is at least 700 m, for example is about 750 m.
10. Pump assembly for providing a downhole pump, preferably a down hole pump according to one or more of the preceding claims and/or for enabling a method according to one or more of the preceding claims, the pump assembly comprising;
- a pump tubular, either as a single tubular or in the form of one or more tubular sections to be combined into a pump tubular, which pump tubular is configured to be mounted in a well bore tubular such that the pump tubular and the wellbore tubular define an annular volume between the pump tubular and a wellbore tubular, wherein the pump tubular comprises an interior space that extends between an inlet end of the pump tubular and an outlet end of the pump tubular, wherein a one-way inlet valve is provided in the interior space of the pump tubular, wherein a one-way outlet valve is provided in the interior space of the pump tubular and above the inlet valve, and wherein the inlet valve and the outlet valve between them define a pump chamber in the interior space, the pump chamber having a length of at least 300 meters, preferably having a length of at least 700 meters.
11. Pump assembly according to claim 10, wherein the pump assembly further comprises a seal for providing a seal between the wellbore tubular and the pump tubular to enable the annular volume to hold an actuator liquid above the fluid tight seal, and wherein the seal preferably is a packer for also securing the pump tubular inside the wellbore tubular.
12. Pump assembly according to claim 10 or claim 11 , wherein the pump assembly further comprises a pulse generator, preferably comprising an isobaric expansion engine, which pulse generator is configured to periodically generate a pulse, preferably a low frequency pulse, in an actuator liquid in an actuator volume between the pup tubular and a wellbore tubular, for compressing the pump tubular and therefore the pump chamber to thus urge well bore liquid from the pump chamber through the outlet valve.
13. Pump assembly according to one or more of the claims 10-12, wherein the one way valves comprise a valve seat and a valve, wherein the valve seats are mounted in the pump tubular, and wherein the valves are releasable mounted in the valve seats, such that the valves can be removed from the seats, e.g. using a wire line, to provide free access to the well via the pump tubular.
14. Pump assembly according to one or more of the claims 10-13, wherein the pump assembly further comprises a wellbore tubular, e.g. casing tubulars, to be mounted in a wellbore and configured to receive the pump tubular to define a annular pace between the pump tubular and the wellbore tubular.
15. Pump assembly according to one or more of the claims 10-14, wherein the pump assembly further comprises one or more spacers for positioning the pump tubular concentric with the wellbore tubular, the spacers comprising two or more arms, which spacer or spacers is or are to be mounted at or near a one-way valve with the two or more arms extending in a radial direction from the pump tubular to the wellbore tubular.
16. Pump assembly according to one or more of the claims 10-15, wherein the pump tubular has an e-modulus in the range of 18.000 Mpa - 24.000 Mpa, preferably in the range of 20.000 Mpa - 22.000 Mpa, for example 21.000 Mpa.
17. Pump assembly according to one or more of the claims 10-16, wherein the pump tubular has an outside diameter in the range of 200 mm - 3000 mm, preferably in the range of 220 mm - 260 mm, for example has an outside diameter of 244 mm.
18. Pump assembly according to one or more of the claims 10-17, wherein the pump tubular has a wall thickness in the range of 6 mm - 16 mm, preferably in the range of 9 mm - 13 mm, for example has a wall thickness of 12,5 mm.
19. Pump assembly according to one or more of the claims 10-18, wherein the pump tubular is configured such that when it comprises two pump chambers and the length of the combined pump chambers is 1500m, a pressure in the actuator volume in the range of 28-32 bar, for example 30 bar, causes a volume change in the range of 0,15 m3 - 0,25 m3.
20. Pump assembly according to one or more of the claims 10-19, wherein the pump assembly comprises a wellbore tubular having inside diameter in the range of 28 cm - 32 cm, for example having an inside dimeter 32 cm, and the pump tubular has an outside diameter in the range of 22 cm - 28 cm, for example has an outside diameter of 25 cm.
21. Pump assembly according to one or more of the claims 10-20, wherein, when the pump tubular is mounted in the wellbore tubular and the bottom seal is provided between the pump tubular and the wellbore tubular, the actuator volume enclosed by the pump tubular and the wellbore tubular and the bottom seal has a volume in the range of 15 litre/meter - 20 litre/meter, for example has a volume of 17,5 litre/meter.
22. Use of a down hole pump according to claim 8 or claim 9, or of a pump assembly according to one or more of the claims 10-21 in a method according to one or more of the claims 1-7.
PCT/NL2019/050663 2018-10-04 2019-10-04 Method and downhole pump for pumping liquid through a wellbore Ceased WO2020071915A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL2021761 2018-10-04
NL2021761A NL2021761B1 (en) 2018-10-04 2018-10-04 Method and downhole pump for pumping liquid through a wellbore

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US12180806B2 (en) 2020-11-12 2024-12-31 Moog Inc. Subsurface safety valve actuator

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GB2150224A (en) * 1983-11-23 1985-06-26 Merrill Pumps & Engineering Li Fluid-operated diaphragm pump
WO1992014929A1 (en) * 1991-02-22 1992-09-03 Qed Environmental Systems, Inc. Pump apparatus for fluid sampling and collection, and the like
US5704772A (en) * 1995-11-08 1998-01-06 Breslin; Michael K. Controller less resilient bladder pump for reduced diameter casing with long cycle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2150224A (en) * 1983-11-23 1985-06-26 Merrill Pumps & Engineering Li Fluid-operated diaphragm pump
WO1992014929A1 (en) * 1991-02-22 1992-09-03 Qed Environmental Systems, Inc. Pump apparatus for fluid sampling and collection, and the like
US5704772A (en) * 1995-11-08 1998-01-06 Breslin; Michael K. Controller less resilient bladder pump for reduced diameter casing with long cycle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12180806B2 (en) 2020-11-12 2024-12-31 Moog Inc. Subsurface safety valve actuator

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