Gas-Driven Pumping Device and a Method for Downhole Pumping of a Liquid in a Well

Abstract

A gas-driven pumping device and a method for downhole pumping of a liquid from at least one liquid source in a well and onto at least one receiving region for the liquid. The pumping device comprises a pressure manipulation chamber having a lower chamber portion and an upper chamber portion, wherein the pressure manipulation chamber is connected in a flow-communicating manner to a liquid supply channel; a liquid discharge channel; a gas supply channel; and a gas discharge channel. By alternately lowering and increasing the gas pressure (Pchamber), liquid is pumped from the liquid source and onwards to the receiving region via the pressure manipulation chamber.

Description

AREA OF INVENTION

This invention concerns a gas-driven pumping device and a method for allowing pumping of a liquid, for example water and/or oil, out of a well or within the well. The liquid may be comprised of water or oil emanating from a subsurface production formation connected to the well. The liquid may consist of a separated liquid, for example water-containing liquid, emanating from a downhole separator connected to such a production formation.

Advantageously, the invention may be used in connection with downhole separation of oil and water emanating from a hydrocarbon- and water-containing production flow, as simultaneously injecting water-containing liquid into a subsurface disposal formation.

The invention may also be used in all types of wells, including deviated wells and horizontal wells.

1. Background of the Invention

The background of the invention is an industrial need for a simple, operationally reliable and cost-efficient pumping solution for downhole use in a well.

2. Prior Art and Disadvantages Thereof

The prior art comprises many types of conventional and submersible pumping devices for use in a well, including piston pumps, displacement pumps, turbine pumps, centrifugal pumps, etc. Given that a person skilled in the area will be familiar with such pumps, a further description is considered unnecessary.

Such conventional downhole pumps generally have relatively complex constructions in common, and/or they have many movable parts. Moreover, they oftentimes receive mechanical, hydraulic or electric power from the surface, which requires suitable connections and equipment in order to provide the driving power. Normally, they are also comprehensive and/or complicated to drive, inspect and maintain. Generally, this causes them to have a limited lifetime and/or a limited area of application, especially in deep wells. This is generally reflected as operational and cost-related disadvantages.

Thus, there is a need in the industry for a substantially simpler, operationally reliable and more cost-efficient pumping solution applicable also under a series of different well conditions, including deep wells of high pressure and high temperature.

OBJECT OF THE INVENTION

The object of the invention is to avoid or substantially reduce the disadvantages of the prior art by providing a novel pumping device and method of pumping a liquid in a well.

How to Achieve the Object

The object is achieved through features disclosed in the following description and in the subsequent claims.

Furthermore, the invention presupposes that a person skilled in the area will employ relevant knowledge in the area, including various known well technology and well equipment, and to the degree necessary in order to adapt the invention to the well conditions and requirements at hand. Such known well equipment may include suitable well packers, valves, control equipment, various types of pipes, conduits and materials, etc. Also this will not be discussed any further given that this is considered known to the skilled person.

According to a first aspect of the invention, a gas-driven pumping device for pumping a liquid from at least one liquid source in a well and onto at least one receiving region for the liquid is provided, the liquid source having a pressure (P_source) and the receiving region having a pressure (P_receiving). The pumping device is located in the well.

The distinctive characteristic of the pumping device is that it comprises at least one pressure manipulation chamber extending in the longitudinal direction of the well and including a lower chamber portion and an upper chamber portion; and

• • wherein said pressure manipulation chamber is connected in a flow-communicating manner to the following channels:
    • at least one liquid supply channel connecting the pressure manipulation chamber to said liquid source, the liquid supply channel including at least one first check valve for allowing liquid flow only to the pressure manipulation chamber;
    • at least one liquid discharge channel connecting the lower chamber portion of the pressure manipulation chamber to said liquid receiving region, the liquid discharge channel including at least one second check valve for allowing liquid flow only from the pressure manipulation chamber;
    • at least one gas supply channel connecting the pressure manipulation chamber to at least one gas source containing a pressurized manipulation gas, the gas supply channel including at least one first control valve structured for selective introduction of manipulation gas into the pressure manipulation chamber, and also for regulation of the pressure (P_chamber) of the gas therein; and
    • at least one gas discharge channel leading out of the upper chamber portion of the pressure manipulation chamber, the gas discharge channel including at least one second control valve structured for selective discharge of manipulation gas from the pressure manipulation chamber, and also for regulation of the pressure (P_chamber) of the gas therein.

Thereby, the pumping device is structured so as to be able to direct manipulation gas out of the pressure manipulation chamber and also lower the gas pressure (P_chamber) therein to a lower pressure (P_lower) at which a resulting pressure difference (P_source-P_lower) will drive the liquid from the liquid source and into the pressure manipulation chamber via the liquid supply channel. Thereby, the pumping device is also structured so as to then be able to direct manipulation gas into the pressure manipulation chamber and increase the gas pressure (P_chamber) therein to an upper pressure (P_upper) at which a resulting pressure difference (P_upper-P_receiving) will drive the liquid from the pressure manipulation chamber and onwards to the receiving region via said liquid discharge channel. In this manner the pumping device is structured so as to be able to alternately lower and increase the gas pressure (P_chamber) in the pressure manipulation chamber, the course of which represents one operating cycle, thereby being able to pump liquid from the liquid source and onwards to the receiving region via the pressure manipulation chamber.

Thus, the present pumping device is based on the ability to change the gas pressure(P_chamber) in the pressure manipulation chamber within a large pressure range, and potentially within several tens of bars. This is achieved by virtue of said gas source being pressurized to a suitable pressure level capable of at least resulting in the particular upper pressure (P_upper) in the pressure manipulation chamber. The gas source may thus be arranged with such a suitable pressure level, or a gas source pressurized at least to such a pressure level may be selected.

If required, the pressure manipulation chamber may be several hundred meters long and may hold a significant volume of gas and liquid.

In addition, said supply channels and discharge channels from the pressure manipulation chamber may be comprised of, for example, suitable pipes, hoses or annuli between well pipes, or possibly annuli between a well pipe and a wall of a well.

The pumping device may also employ suitable sensors, valve means and control devices for appropriate control of the gas and liquid flow into and out of the pressure manipulation chamber, but also for appropriate control of the liquid's level within the pressure manipulation chamber in the course of said operating cycle. As such, one or several water level stop devices and gas flow control devices may be employed for this purpose. However, such equipment is considered to be prior art and therefore will not be discussed in detail.

Said water level stop device may, for example, comprise one or several floats, float seats and sensors known per se capable of distinguishing a liquid from a gas at one or several water levels within the pressure manipulation chamber. Such sensors may distinguish differences in physical properties of the liquid and the gas, for example differences in pressure, density, temperature, resistivity, acoustic travel, time, optical properties and alike.

As an addition or alternative, said gas flow control device may, for example, be connected devices and sensors known per se capable of distinguishing different properties of a liquid and/or gas at one or several water levels within the pressure manipulation chamber. The gas flow control device may then be structured so as to be able to register such differences and/or properties and, based on this, may allow control of said flow of overpressured manipulation gas to and from the pressure manipulation chamber. Said sensors may, for example, distinguish differences in pressure, density, temperature, resistivity, acoustic travel time, optical properties and alike.

Moreover, said manipulation gas may consist of any suitable gas, for example a hydrocarbon gas, air, carbon dioxide or nitrogen.

In one embodiment, said liquid supply channel is connected in a flow-communicating manner to at least one water production formation connected to the well, the water production formation thus constituting said liquid source; and whereas said liquid discharge channel is connected in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for water emanating from the water production formation.

Thereby, the present pumping device may be used, for example, to pump and produce water emanating from a subsurface water reservoir, for example a ground water occurrence. Generally, such a water reservoir contains hydrostatically pressurized water, which normally implies that the water will not flow to the surface by itself.

In another embodiment, said liquid supply channel is connected in a flow-communicating manner to at least one oil production formation connected to the well, the oil production formation thus constituting said liquid source; whereas said liquid discharge channel is connected in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for oil emanating from the oil production formation.

Thereby, the present pumping device may be used, for example, to pump and produce oil emanating from a subsurface oil reservoir. Thus, the present pumping device may replace a so-called jacking pump, which comprises a downhole oscillating piston pump connected to a mechanical driving device on the surface via a long pump rod extending to the surface.

In the two preceding embodiments, said gas discharge channel may comprise at least one gas bleed channel filled with manipulation gas for selective discharge of so-called lift gas into said liquid discharge channel, whereby a gas pressure gradient will be present in the gas bleed channel, whereas a liquid pressure gradient will be present in the liquid discharge channel;

• • wherein the gas-filled gas bleed channel connects the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the liquid discharge channel where the liquid (i.e. water or oil) has a liquid pressure (P_shallower) and;
  • wherein said shallower depth level is selected at a depth where the liquid pressure (P_shallower), via the gas pressure gradient in the gas bleed channel, will result in said lower gas pressure (P_lower) in the pressure manipulation chamber, insofar as the lower gas pressure (P_lower) will be substantially smaller than a corresponding liquid pressure at the same level in the liquid discharge channel.

Thereby, the difference between the densities of the manipulation gas and the liquid flow is utilized to provide the lower gas pressure (P_lower) in the pressure manipulation chamber. Thereby, the pumping device is also structured so as to be able to selectively direct manipulation gas into the liquid discharge channel as lift gas for the liquid (i.e., water or oil).

In this connection, said gas source may be comprised of at least one of the following gas sources:

• • a gas source at the surface; and
  • a gas source in a subsurface formation.

A further embodiment will now be described, the embodiment being specifically directed toward downhole separation and injection of water separated from a hydrocarbon- and water-containing production flow emanating from a subsurface reservoir.

According to this embodiment, said liquid supply channel is connected in a flow-communicating manner to a water-containing liquid in at least one hydrocarbon-water-separator located in the well, the separator constituting said liquid source;

• • wherein said separator is connected in a flow-communicating manner to a hydrocarbon- and water-containing production flow emanating from at least one production formation connected to the well;
  • wherein the separator is structured so as to be able to at least separate said production flow into said water-containing liquid and into a hydrocarbon-containing liquid;
  • wherein the hydrocarbon-containing liquid in the separator is connected in a flow-communicating manner to at least one production channel for production of the hydrocarbon-containing liquid; and
  • wherein said liquid discharge channel is connected in a flow-communicating manner to at least one disposal formation connected to the well, the disposal formation constituting said receiving region for separated, water-containing liquid emanating from the separator.

The expressions water-containing liquid and hydrocarbon-containing liquid do not presuppose 100% presence of water and hydrocarbons, respectively, but refer herein to main constituents of water and hydrocarbons, respectively.

Furthermore, the hydrocarbon-containing part of the production flow may contain only hydrocarbon liquid, possibly a mixture of hydrocarbon liquid and hydrocarbon gas.

Preferably, said disposal formation is porous and permeable, but it may also be non-porous and impermeable. In order to be able to pump and inject the separated and water-containing liquid into the disposal formation, the fluid pressure in the pores of the disposal formation (the pore pressure), and/or the fracture pressure of the formation, must be overcome. This circumstance must be accounted for when said upper gas pressure (P_upper) in the pressure manipulation chamber is to be determined.

In this embodiment, which is directed toward production of both hydrocarbons and water, said gas discharge channel may comprise at least one gas bleed channel filled with manipulation gas for selective discharge of lift gas into said production channel, whereby a gas pressure gradient will be present in the gas bleed channel, whereas a liquid pressure gradient will be present in the production channel;

• • wherein the gas-filled gas bleed channel connects the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the production channel where the hydrocarbon-containing liquid has a liquid pressure (P_shallower); and
  • wherein said shallower depth level is selected at a depth where the liquid pressure (P_shallower), via the gas pressure gradient in the gas bleed channel, will result in said lower gas pressure (P_lower) in the pressure manipulation chamber, insofar as the lower gas pressure (P_lower) will be substantially smaller than a corresponding liquid pressure at the same level in the production channel.

Thereby, the difference between the densities of the manipulation gas and the hydrocarbon-containing liquid is utilized to provide the lower gas pressure (P_lower) in the pressure manipulation chamber. Thereby, the pumping device is also structured so as to be able to selectively direct manipulation gas into the production channel as lift gas for the hydrocarbon-containing liquid.

In this connection, said gas source may be comprised of at least one of the following gas sources:

• • a gas source at the surface;
  • a gas source in a subsurface formation; and
  • a gas source in the form of gas separated from the hydrocarbon- and water-containing production flow emanating from said production formation.

Said at least one hydrocarbon-water-separator may comprise at least one cyclone separator. U.S. Pat. No. 5,711,374 (corresponding to WO 94/13930) and U.S. Pat. No. 5,296,153 (corresponding to WO 94/18432) describe cyclone separators capable of being used in connection with the present invention. Both of these publications describe injection of separated water into a subsurface disposal formation. However, the water injection takes place by means of conventional downhole pumps, which are comprised by the prior art, including the pump types mentioned above, among others.

As an addition or alternative, said at least one hydrocarbon-water-separator may also comprise at least one gravity separator. U.S. Pat. No. 6,092,599 (corresponding to WO 99/15755) describes a downhole oil-water separation system capable of being used in connection with the present invention, the separation system of which is based on gravity separation of a hydrocarbon-containing production flow. This separation system is shown used in a vertical well. Conventional downhole pumps are used to produce separated water to the surface, or to inject the water into a subsurface disposal formation.

If the well is a so-called horizontal well, the gravity separator may be comprised of a horizontal gravity separator located in a horizontal portion of the well, the gravity separator of which may be several hundred meters long. If required, the horizontal well may also comprise several horizontal gravity separators. U.S. Pat. No. 6,277,286 (corresponding to WO 98/41304) describes a horizontal gravity separator capable of being used in connection with the present invention. Also this publication describes use of conventional downhole pumps for injecting separated water into a subsurface disposal formation, possibly via a sidetrack well.

If required, the at least one hydrocarbon-water-separator may also comprise at least one gas separation device for separation of gas from said production flow. U.S. Pat. No. 6,691,781 describes a horizontal gravity separator for separation of both gas, water and oil from a production flow. Also this type of separator may be used in connection with the present invention. Among other things, the publication describes injection of separated gas and/or water into a subsurface disposal formation. Also here conventional downhole pumps are used for pumping of separated liquids, whereas a turbine-driven gas compressor is used for pumping of separated gas.

Yet further, the pressure manipulation chamber may be located at a distance from the at least one separator. If required or desirable, the pressure manipulation chamber may be located several hundred meters away from said separator. This follows from the present pumping device being structured so as to be able to change the gas pressure (P_chamber) in the pressure manipulation chamber within a large pressure range, whereby a correspondingly large pressure height (and lifting height) is obtained for the pumping device. This feature provides the present pumping device with a substantial advantage with respect to known suction pumps, which are based on generating an underpressure relative to an ambient pressure, generally atmospheric air pressure. Such a suction pump will therefore be able to provide a driving pressure difference limited upwards to ca. 1 bar at the suction side of the pump, which corresponds to a maximum pressure height (and lifting height) of ca. 10 m, depending on the density of the liquid to be pumped. For this reason, suction pumps are not useful in most wells. For that matter, this also applies to other types of pumps having limited pressure height (and lifting height).

Moreover, said at least one disposal formation may be situated shallower and/or deeper than the at least one production formation. As an addition or alternative, the at least one disposal formation may comprise at least one disposal layer in the at least one production formation, for example a water-containing layer underlying a hydrocarbon-containing layer of the same formation.

The pressure manipulation chamber may also have various designs. Thus, the pressure manipulation chamber may be located in or on the outside of a pipe in the well, for example a production tubing, casing or coiled tubing. The pressure manipulation chamber may also be located in an annulus in the well, for example between two well pipes or between a well pipe and the wall of a well.

Advantageously, the present pumping device may comprise at least two pressure manipulation chambers structured for cooperative pumping of liquid from said liquid source and onwards to said receiving region; and

• • wherein said pressure manipulation chambers are arranged with a phase-lagged operating cycle relative to each other, whereby a smoother induction and pumping of liquid is achieved.

If the pumping device is provided with two cooperative pressure manipulation chambers, the chambers may be arranged with opposite operating cycle relative to each other. The pumping device may possibly comprise several such pairs of cooperative pressure manipulation chambers.

According to a second aspect of the invention, a method of pumping a liquid from at least one liquid source in a well and onto at least one receiving region for the liquid is provided, the liquid source having a pressure (P_source) and the receiving region having a pressure (P_receiving).

The distinctive characteristic of the method is that it comprises:

• • locating at least one gas-driven pumping device in the well, wherein the pumping device comprises at least one pressure manipulation chamber extending in the longitudinal direction of the well and including a lower chamber portion and an upper chamber portion, and wherein said pressure manipulation chamber is connected in a flow-communicating manner to the following channels:
    • at least one liquid supply channel connecting the pressure manipulation chamber to said liquid source, the liquid supply channel including at least one first check valve for allowing liquid flow only to the pressure manipulation chamber;
    • at least one liquid discharge channel connecting the lower chamber portion of the pressure manipulation chamber to said liquid receiving region, the liquid discharge channel including at least one second check valve for allowing liquid flow only from the pressure manipulation chamber;
    • at least one gas supply channel connecting the pressure manipulation chamber to at least one gas source containing a pressurized manipulation gas, the gas supply channel including at least one first control valve structured for selective introduction of manipulation gas into the pressure manipulation chamber, and also for regulation of the pressure (P_chamber) of the gas therein; and
    • at least one gas discharge channel leading out of the upper chamber portion of the pressure manipulation chamber, the gas discharge channel including at least one second control valve structured for selective discharge of manipulation gas from the pressure manipulation chamber, and also for regulation of the pressure (P_chamber) of the gas therein.

The method also comprises the following steps:

• (A) directing manipulation gas out of the pressure manipulation chamber and also lowering the gas pressure (P_chamber) therein to a lower pressure (P_lower) at which a resulting pressure difference (P_source-P_lower) drives the liquid from the liquid source and into the pressure manipulation chamber via the liquid supply channel;
• (B) filling the liquid up to an upper liquid level in the pressure manipulation chamber;
• (C) directing manipulation gas into the pressure manipulation chamber and increasing the gas pressure (P_chamber) therein to an upper pressure (P_upper) at which a resulting pressure difference (P_upper-P_receiving) drives the liquid from the pressure manipulation chamber and onwards to the receiving region via said liquid discharge channel;
• (D) driving the liquid down to a lower liquid level in the pressure manipulation chamber; and
• (E) repeating steps (A)-(D), the course of which represents one operating cycle, thereby maintaining the pumping of liquid from the liquid source and onwards to the receiving region via the pressure manipulation chamber.

For that matter, the aforementioned comments with respect to constructive features of the pumping device according to the first aspect of the invention, also apply to the pumping device according to the present method.

In one embodiment of the method, it also comprises the following steps:

• • connecting said liquid supply channel in a flow-communicating manner to at least one water production formation connected to the well, the water production formation thus constituting said liquid source; and
  • connecting said liquid discharge channel in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for water emanating from the water production formation.

In another embodiment of the method, it also comprises the following steps:

• • connecting said liquid supply channel in a flow-communicating manner to at least one oil production formation connected to the well, the oil production formation thus constituting said liquid source; and
  • connecting said liquid discharge channel in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for oil emanating from the oil production formation.

Yet further, the method may comprise the following steps:

• • using a gas discharge channel comprising at least one gas bleed channel and filling it with manipulation gas for selective discharge of lift gas into said liquid discharge channel, whereby a gas pressure gradient is present in the gas bleed channel, whereas a liquid pressure gradient is present in the liquid discharge channel;
  • by means of said gas bleed channel, connecting the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the liquid discharge channel where the liquid (i.e. water or oil) has a liquid pressure (P_shallower); and
  • selecting said shallower depth level at a depth where the liquid pressure (P_shallower), via the gas pressure gradient in the gas bleed channel, results in said lower gas pressure (P_lower) in the pressure manipulation chamber, insofar as the lower gas pressure (P_lower) is substantially smaller than a corresponding liquid pressure at the same level in the liquid discharge channel.

Thereby, the difference between the densities of the manipulation gas and the liquid is utilized to provide the lower gas pressure (P_lower) in the pressure manipulation chamber. Thereby, the pumping device is also structured to selectively direct manipulation gas into the liquid discharge channel as lift gas for the liquid (i.e. water or oil).

In this connection, said gas source may be comprised of at least one of the following gas sources:

• • a gas source at the surface; and
  • a gas source in a subsurface formation.

The method may also be directed specifically toward downhole separation and injection of water being separated from a is hydrocarbon- and water-containing production flow emanating from a subsurface reservoir.

Thus, the method may also comprise the following steps:

• • connecting said liquid supply channel in a flow-communicating manner to a water-containing liquid in at least one hydrocarbon-water-separator located in the well, the separator constituting said liquid source;
    • wherein said separator is connected in a flow-communicating manner to a hydrocarbon- and water-containing production flow emanating from at least one production formation connected to the well; and
    • wherein the separator is structured so as to be able to at least separate said production flow into said water-containing liquid and into a hydrocarbon-containing liquid;
  • connecting the hydrocarbon-containing liquid in the separator in a flow-communicating manner to at least one production channel for production of the hydrocarbon-containing liquid; and
  • connecting said liquid discharge channel in a flow-communicating manner to at least one disposal formation connected to the well, the disposal formation constituting said receiving region for separated, water-containing liquid emanating from the separator.

This embodiment of the method may also comprise the following steps:

• • using a gas discharge channel comprising at least one gas bleed channel and filling it with manipulation gas for selective discharge of lift gas into said production channel, whereby a gas pressure gradient is present in the gas bleed channel, whereas a liquid pressure gradient is present in the production channel;
  • by means of said gas bleed channel, connecting the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the production channel where the hydrocarbon-containing liquid has a liquid pressure (P_shallower); and
  • selecting said shallower depth level at a depth where the liquid pressure (P_shallower), via the gas pressure gradient in the gas bleed channel, results in said lower gas pressure (P_lower) in the pressure manipulation chamber, insofar as the lower gas pressure (P_lower) is substantially smaller than a corresponding liquid pressure at the same level in the production channel.

Thereby, the difference between the densities of the manipulation gas and the hydrocarbon-containing liquid is utilized to provide the lower gas pressure (P_lower) in the pressure manipulation chamber. Thereby, the pumping device is also structured to selectively direct manipulation gas into the production channel as lift gas for the hydrocarbon-containing liquid.

In this connection, said gas source may be comprised of at least one of the following gas sources:

• • a gas source at the surface;
  • a gas source in a subsurface formation; and
  • a gas source in the form of gas being separated from the hydrocarbon- and water-containing production flow emanating from said production formation.

Said at least one hydrocarbon-water-separator may comprise at least one cyclone separator and/or at least one gravity separator.

If the well is a so-called horizontal well, the gravity separator may be comprised of a horizontal gravity separator, which is being located in a horizontal portion of the well.

If required, the at least one hydrocarbon-water-separator may also comprise at least one gas separation device for separation of gas from said production flow.

Yet further, the pressure manipulation chamber may be located at a distance from the at least one separator, and optionally several hundred meters away from said separator, which is not possible with conventional suction pumps or similar.

As mentioned, said at least one disposal formation may be situated shallower and/or deeper than the at least one production formation. As an addition or alternative, the at least one disposal formation may comprise at least one disposal layer in the at least one production formation.

The pressure manipulation chamber may also be located in or on the outside of a pipe in the well, or it may be located in an annulus in the well.

Advantageously, the method may also comprise the following steps:

• • locating at least two of said pumping devices in the well, wherein each pumping device includes at least one pressure manipulation chamber;
  • structuring the pumping devices for cooperative pumping of liquid from said liquid source and onwards to said receiving region; and
  • arranging the pumping devices with a phase-lagged operating cycle relative to each other, whereby a smoother induction and pumping of liquid is achieved.

Thus, at least two pumping devices may be connected in parallel or in series, depending on the particular need.

ADVANTAGES OF THE INVENTION

This invention is distinguished from the prior art by virtue of:

• • requiring few equipment components;
  • requiring few movable components;
  • providing a simple and reliable pumping device with a long lifetime;
  • allowing its application in new wells and in existing wells;
  • allowing its application in both vertical wells, deviated wells and in horizontal wells;
  • allowing its application in pure water production wells or oil production wells not capable of driving the production flow to the surface by itself;
  • allowing its application in wells producing a mixture of hydrocarbons and water, wherein the water is being separated in a downhole separator and is injected into a subsurface disposal formation/-layer, whereas hydrocarbons are being produced to the surface;
  • allowing for injection of separated water into a disposal formation/-layer situated shallower and/or deeper than an associated production formation; and
  • allowing its application together with a gas lift system in the well.

SHORT DESCRIPTION OF THE DRAWINGS

In the following, two non-limiting examples of embodiments of the present invention are described and referred to in the accompanying figures, in which:

FIGS. 1-6 show a first embodiment of the invention; and

FIGS. 7-12 show a second embodiment of the invention.

The attached figures are strongly simplified and show only the essential and symbolically depicted components of the invention. The shape, relative dimensions and mutual positions of the components are also distorted. In the following, equal, equivalent or corresponding details in the figures will generally be assigned the same reference numeral.

DESCRIPTION OF EXAMPLES OF EMBODIMENTS OF THE INVENTION

FIGS. 1-6 show a first embodiment of a gas-driven pumping device 2 located in a subsurface well 4 including, among other things, an outer casing 6 and an inner production tubing 8. Although the well 4 is shown as a vertical well in all of FIG. 1-12, in practice it may also be a deviated well or a horizontal well. The casing 6 is also provided with perforations 10, 12, which are positioned vis-à-vis a production formation 14 and a shallower disposal formation 16, respectively, the disposal formation 16 having a pressure (P_receiving) and constituting a receiving region for liquid.

The pumping device 2 comprises a pressure manipulation chamber 18 located in an annulus 19 in the well 4, the annulus of which may extend for several hundred meters in the longitudinal direction of the well 4. The pressure manipulation chamber 18 is defined between the casing 6 and the production tubing 8, and between a first (upper) well packer 20 and a second (lower) well packer 22. In this embodiment, the second well packer 22 is located immediately above the disposal formation 16, whereas a third well packer 24 is located immediately below the disposal formation 16. By so doing, an injection annulus 26 is defined between the second well packer 22 and the third well packer 24, and between the casing 6 and the production tubing 8.

The production tubing 8 extends deeper down into the well 4 and onto an oil-water gravity separator 28, which is shown very schematically in all of FIGS. 1-12. The gravity separator 28 is connected, among other things, to the production tubing 8, but it is also connected in flow-communicating manner to said production formation 14 via at least one inlet 30 in the separator 28, and via the perforations 10 in the casing 6. From the production formation 14, an oil- and water-containing production flow 32 is directed into the well 4 and further into the gravity separator 28, which has a pressure (P_source). In the gravity separator 28, which constitutes a liquid source for the pumping device 2, the production flow 32 is separated into a lower water layer 34 and into an upper oil layer 36. In the present separator 28, the separation will take place in a natural manner owing to a density difference between water 34 and oil 36. As for the rest, the upper oil layer is connected in a flow-communicating manner to the production tubing 8 for production of oil 36 to the surface of the well 4.

Although the separator 28 is shown located in a vertical well in all of FIGS. 1-12, it may just as well be located in a deviated well or in a horizontal well. In a horizontal well, the separator may be comprised of a horizontal gravity separator located in a horizontal portion of the well. Other types of downhole separators may also be used, for example cyclone separators.

Yet further, the pressure manipulation chamber 18, which includes a lower chamber portion 38 and an upper chamber portion 40, is connected in a flow-communicating manner to the following flow channels: a water supply pipe 42, a water discharge pipe 44, a gas supply pipe 46 and a gas discharge pipe 48.

Said water supply pipe 42 connects the pressure manipulation chamber 18 to the lower water layer 34 in the separator 28. The water supply pipe 42 is provided with a first check valve 50 for allowing water flow only to the pressure manipulation chamber 18. The possible flow direction is indicated with a black arrow on all of FIGS. 1-12. Yet further, the pipe 42 has been inserted in a pressure-sealing manner through said second and third well packers 22, 24.

Said water discharge pipe 44 connects the lower chamber portion 38 of the pressure manipulation chamber 18 in a flow-communicating manner to said injection annulus 26, which is connected in a flow-communicating manner to said disposal formation 16 via the perforations 12 in the casing 6. The water discharge pipe 44 is provided with a second check valve 52 for allowing water flow only from the pressure manipulation chamber 18 and into the injection annulus 26. The possible flow direction is indicated with a black arrow on all of FIGS. 1-12. Yet further, the pipe 44 has been inserted in a pressure-sealing manner through said second well packer 22.

As for the rest, said first and second check valves 50, 52 are preferably structured so as to open at a specific pressure level, which is adapted to the well conditions and purposes in question.

Said gas supply pipe 46 connects the pressure manipulation chamber 18 to a gas source 54 containing a pressurized manipulation gas 56, which in the present embodiments is comprised of hydrocarbon gas. The gas source 54 is shown schematically in all of FIGS. 1-12. Alternatively, manipulation gas 56 may be supplied to the pressure manipulation chamber 18 directly from a pressurized annulus 19 overlying said first well packer 20. The gas supply pipe 46 is provided with a first control valve 58 structured for selective introduction of manipulation gas 56 into the pressure manipulation chamber 18, and also for regulation of the pressure (P_chamber) of the gas 56 therein. Any suitable valve means with associated cables, couplings and regulation devices (not shown) may be used for this purpose. Yet further, the pipe 46 has been inserted in a pressure-sealing manner through the first well packer 20.

Said gas discharge pipe 48 leads out of the upper chamber portion 40 of the pressure manipulation chamber 18 and directly into the production tubing 8. The gas discharge pipe 48 is provided with a second control valve 60 structured for selective discharge of manipulation gas 56 from the pressure manipulation chamber 18, and also for regulation of the pressure (P_chamber) of the gas 56 therein. Thereby, the manipulation gas 56 functions as a lift gas 56′ for the oil 36 in the production tubing 8. Also here any suitable valve means with associated cables, couplings and regulation devices (not shown) may be used for this purpose.

The present method will now be described whilst referring to FIGS. 1-6. In all of FIGS. 1-12, the production flow 32, the flow of water 34, and the flow of oil 36 are indicated with hachured arrows, white arrows and black arrows, respectively.

FIG. 1 shows the start-up of the pumping device 2, wherein said first control valve 58 is open, and manipulation gas 56 is directed into the pressure manipulation chamber 18 via said gas supply pipe 46 in order to pressurize the chamber 18 to a gas pressure (P_chamber). The gas flow direction is indicated with a black arrow at the outlet of the gas supply pipe 46. The gas pressure (P_chamber) chamber) is increased to a level in vicinity of the opening pressure for said second check valve 52 in the water discharge pipe 44, and to a level exceeding the liquid pressure in the production tubing 8 positioned vis-à-vis said second control valve 60.

Then the first control valve 58 is closed, whereas the second control valve 60 is opened. Thereby, manipulation gas 56 is directed out of the pressure manipulation chamber 18 via said gas discharge pipe 48 and lowers the gas pressure (P_chamber) in the chamber 18 to a lower pressure (P_lower) at which a resulting pressure difference (P_source-P_lower) drives water 34 from the separator 28 and onwards into the pressure manipulation chamber 18 via the water supply pipe 42. Simultaneously, manipulation gas 56 is directed into the production tubing 8 as said lift gas 56′ for the oil 36 flowing therein. The gas flow direction is indicated with a black arrow at the outlet of the gas discharge pipe 48. This is shown in FIG. 2.

FIGS. 3 and 4 show two different stages the course of filling water 34 into the pressure manipulation chamber 18. The water 34 is filled up to an upper water level 62 in the pressure manipulation chamber 18, the discharge of manipulation gas 56 simultaneously decreasing. This is shown in FIG. 4.

Then, the second control valve 60 is closed, whereas the first control valve 58 is opened. Thereby, pressurized manipulation gas 56 is directed from the gas source 54 and into the pressure manipulation chamber 18 and increases the gas pressure (P_chamber) therein to an upper pressure (P_upper) at which a resulting pressure difference (P_upper-P_receiving) drives water 34 from the pressure manipulation chamber 18 and into the injection annulus 26 via the water discharge pipe 44.

Simultaneously, water 34 is driven further into the disposal formation 16 via the perforations 12 in the casing 6. FIGS. 5 and 6 show two different stages in the course of draining water 34 from the pressure manipulation chamber 18. By means of the upper gas pressure (P_upper), the water 34 is driven and drained down to a lower water level 64 in the pressure manipulation chamber 18. The latter is shown in FIG. 6. This course of events concludes an operating cycle for the pumping device 2. This operating cycle is illustrated in FIGS. 2-6 and is repeated in order thus to maintain the pumping of water 34 from the separator 28 and further into the disposal formation 16 via the pressure manipulation chamber 18, among others.

FIGS. 7-12 show a second embodiment of a gas-driven pumping device 2 according to the invention. This second embodiment comprises most of the central elements of the first embodiment of the invention.

This embodiment, however, comprises a pressure manipulation chamber 18 located as a separate unit on the outside of said production tubing 8, and in said annulus 19 in the well 4.

A second difference is that the pressure manipulation chamber 18 is located at a distance from, and shallower than, both the separator 28 and the disposal formation 16.

A third difference is that said gas discharge pipe 48 now has been replaced by a gas bleed pipe 48′ filled with manipulation gas 56 for selective discharge of lift gas 56′ into the production tubing 8. Thereby, a gas pressure gradient will be present in the gas bleed pipe 48′, whereas an oil pressure gradient will be present in the production tubing 8. Similar to the preceding embodiment, the gas-filled gas bleed pipe 48′ is also provided with a second control valve 60 for selective discharge of manipulation gas 56, and also for regulation of the gas pressure (P_chamber) in the pressure manipulation chamber 18. Furthermore, the gas bleed pipe 48′ is provided with a third check valve 66 for allowing gas flow only from the pressure manipulation chamber 18. The possible gas flow direction is indicated with a black arrow in all of FIGS. 7-12. The gas bleed pipe 48′ connects the upper chamber portion 40 of the pressure manipulation chamber 18 in a flow-communicating manner to a shallower depth level 68 in the production tubing 8 where the oil 36 has an oil pressure (P_shallower).

As an alternative (not shown), both a gas discharge pipe 48 and a gas bleed pipe 48′ provided each with a control valve 60, may be used.

This shallower depth level 68 has been chosen at a depth where the oil pressure (P_shallower), via the gas pressure gradient in the gas bleed pipe 48′, will result in said lower gas pressure (P_lower) in the pressure manipulation chamber 18. The gas pressure (P_lower) will be substantially smaller than a corresponding oil pressure at the same level in the production tubing 8. Thereby, the difference between the densities of the manipulation gas 56 and the oil 36 is utilized to provide the lower gas pressure (P_lower) in the pressure manipulation chamber 18. Thereby, also this pumping device 2 is structured so as to be able to selectively direct manipulation gas 56 into the production tubing 8 as lift gas 56′ for the flow of oil 36 from the separator 28.

Claims

1. A gas-driven pumping device for pumping a liquid from at least one liquid source in a well and onto at least one receiving region for the liquid, the liquid source having a pressure (Psource) and the receiving region having a pressure (Preceiving), in which the pumping device is located in the well, wherein the pumping device comprises at least one pressure manipulation chamber extending in the longitudinal direction of the well and including a lower chamber portion and an upper chamber portion; and

wherein said pressure manipulation chamber is connected in a flow-communicating manner to the following channels:

at least one liquid supply channel connecting the pressure manipulation chamber to said liquid source, the liquid supply channel including at least one first check valve for allowing liquid flow only to the pressure manipulation chamber;

at least one liquid discharge channel connecting the lower chamber portion of the pressure manipulation chamber to said liquid receiving region, the liquid discharge channel including at least one second check valve for allowing liquid flow only from the pressure manipulation chamber;

at least one gas supply channel connecting the pressure manipulation chamber to at least one gas source containing a pressurized manipulation gas, the gas supply channel including at least one first control valve structured for selective introduction of manipulation gas into the pressure manipulation chamber, and also for regulation of the pressure (Pchamber) of the gas therein; and

at least one gas discharge channel leading out of the upper chamber portion of the pressure manipulation chamber, the gas discharge channel including at least one second control valve structured for selective discharge of manipulation gas from the pressure manipulation chamber, and also for regulation of the pressure (Pchamber) of the gas therein;

whereby the pumping device is structured so as to be able to direct manipulation gas out of the pressure manipulation chamber and also lower the gas pressure (Pchamber) therein to a lower pressure (Plower) at which a resulting pressure difference (Psource-Plower) will drive the liquid from the liquid source and into the pressure manipulation chamber via the liquid supply channel;

whereby the pumping device also is structured so as to then be able to direct manipulation gas into the pressure manipulation chamber and increase the gas pressure (Pchamber) therein to an upper pressure (Pupper) at which a resulting pressure difference (Pupper-Preceiving) will drive the liquid from the pressure manipulation chamber and onwards to the receiving region via said liquid discharge channel; and

whereby the pumping device is structured so as to be able to alternately lower and increase the gas pressure (Pchamber) in the pressure manipulation chamber, the course of which represents one operating cycle, thereby being able to pump liquid from the liquid source and onwards to the receiving region via the pressure manipulation chamber.

2. The gas-driven pumping device according to claim 1, wherein said liquid supply channel is connected in a flow-communicating manner to at least one water production formation connected to the well, the water production formation thus constituting said liquid source; and

wherein said liquid discharge channel is connected in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for water emanating from the water production formation.

3. The gas-driven pumping device according to claim 1, wherein said liquid supply channel is connected in a flow-communicating manner to at least one oil production formation connected to the well, the oil production formation thus constituting said liquid source; and

wherein said liquid discharge channel is connected in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for oil emanating from the oil production formation.

4. The gas-driven pumping device according to claim 2, wherein said gas discharge channel comprises at least one gas bleed channel filled with manipulation gas for selective discharge of lift gas into said liquid discharge channel, whereby a gas pressure gradient will be present in the gas bleed channel, whereas a liquid pressure gradient will be present in the liquid discharge channel;

wherein the gas-filled gas bleed channel connects the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the liquid discharge channel where the liquid has a liquid pressure (Pshallower); and

wherein said shallower depth level is selected at a depth where the liquid pressure (Pshallower), via the gas pressure gradient in the gas bleed channel, will result in said lower gas pressure (Plower) in the pressure manipulation chamber, insofar as the lower gas pressure (Plower) will be substantially smaller than a corresponding liquid pressure at the same level in the liquid discharge channel;

whereby the difference between the densities of the manipulation gas and the liquid flow is utilized to provide the lower gas pressure (Plower) 1 in the pressure manipulation chamber; and

whereby the pumping device is structured so as to be able to selectively direct manipulation gas into the liquid discharge channel as lift gas for the liquid.

5. The gas-driven pumping device according to claim 1, wherein said gas source is comprised of at least one of the following gas sources:

a gas source at the surface; and

a gas source in a subsurface formation.

6. The gas-driven pumping device according to claim 1, wherein said liquid supply channel is connected in a flow-communicating manner to a water-containing liquid in at least one hydrocarbon-water-separator located in the well, the separator constituting said liquid source;

wherein said separator is connected in a flow-communicating manner to a hydrocarbon- and water-containing production flow emanating from at least one production formation connected to the well;

wherein the separator is structured so as to be able to at least separate said production flow into said water-containing liquid and into a hydrocarbon-containing liquid;

wherein the hydrocarbon-containing liquid in the separator is connected in a flow-communicating manner to at least one production channel for production of the hydrocarbon-containing liquid; and

wherein said liquid discharge channel is connected in a flow-communicating manner to at least one disposal formation connected to the well, the disposal formation constituting said receiving region for separated, water-containing liquid emanating from the separator.

7. The gas-driven pumping device according to claim 6, wherein said gas discharge channel comprises at least one gas bleed channel filled with manipulation gas for selective discharge of lift gas into said production channel, whereby a gas pressure gradient will be present in the gas bleed channel, whereas a liquid pressure gradient will be present in the production channel;

wherein the gas-filled gas bleed channel connects the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the production channel where the hydrocarbon-containing liquid has a liquid pressure (Pshallower); and

wherein said shallower depth level is selected at a depth where the liquid pressure (Pshallower), via the gas pressure gradient in the gas bleed channel, will result in said lower gas pressure (Plower) in the pressure manipulation chamber, insofar as the lower gas pressure (Plower) will be substantially smaller than a corresponding liquid pressure at the same level in the production channel;

whereby the difference between the densities of the manipulation gas and the hydrocarbon-containing liquid is utilized to provide the lower gas pressure (Plower) in the pressure manipulation chamber; and

whereby the pumping device is structured so as to be able to selectively direct manipulation gas into the production channel as lift gas for the hydrocarbon-containing liquid.

8. The gas-driven pumping device according to claim 6, wherein said gas source is comprised of at least one of the following gas sources:

a gas source at the surface;

a gas source in a subsurface formation; and

a gas source in the form of gas separated from the hydrocarbon- and water-containing production flow emanating from said production formation.

9. The gas-driven pumping device according to claim 6, wherein said at least one hydrocarbon-water-separator comprises at least one cyclone separator.

10. The gas-driven pumping device according to claim 6, wherein said at least one hydrocarbon-water-separator comprises at least one gravity separator.

11. The gas-driven pumping device according to claim 10, wherein the gravity separator is comprised of a horizontal gravity separator located in a horizontal portion of the well.

12. The gas-driven pumping device according to claim 6, wherein the pressure manipulation chamber is located at a distance from the at least one separator.

13. The gas-driven pumping device according to claim 6, wherein the at least one disposal formation is situated shallower than the production formation.

14. The gas-driven pumping device according to claim 6, wherein the at least one disposal formation is situated deeper than the production formation.

15. The gas-driven pumping device according to claim 6, wherein the at least one disposal formation comprises at least one disposal layer in the production formation.

16. The gas-driven pumping device according to claim 1, wherein the pressure manipulation chamber is located in a pipe in the well.

17. The gas-driven pumping device according to claim 1, wherein the pressure manipulation chamber is located on the outside of a pipe in the well.

18. The gas-driven pumping device according to claim 1, wherein the pressure manipulation chamber is located in an annulus in the well.

19. The gas-driven pumping device according to claim 1, wherein the pumping device comprises at least two pressure manipulation chambers structured for cooperative pumping of liquid from said liquid source and onwards to said receiving region; and

wherein said pressure manipulation chambers are arranged with a phase-lagged operating cycle relative to each other, whereby a smoother induction and pumping of liquid is achieved.

20. A method of pumping a liquid from at least one liquid source in a well and onto at least one receiving region for the liquid, the liquid source having a pressure (Psource) and the receiving region having a pressure (Preceiving), wherein the method comprises: wherein the method further comprises the following steps:

locating at least one gas-driven pumping device in the well, wherein the pumping device comprises at least one pressure manipulation chamber extending in the longitudinal direction of the well and including a lower chamber portion and an upper chamber portion, and wherein said pressure manipulation chamber is connected in a flow-communicating manner to the following channels:

at least one liquid supply channel connecting the pressure manipulation chamber to said liquid source, the liquid supply channel including at least one first check valve for allowing liquid flow only to the pressure manipulation chamber;

at least one liquid discharge channel connecting the lower chamber portion of the pressure manipulation chamber to said liquid receiving region, the liquid discharge channel including at least one second check valve for allowing liquid flow only from the pressure manipulation chamber;

at least one gas supply channel connecting the pressure manipulation chamber to at least one gas source containing a pressurized manipulation gas, the gas supply channel including at least one first control valve structured for selective introduction of manipulation gas into the pressure manipulation chamber, and also for regulation of the pressure (Pchamber) of the gas therein; and

at least one gas discharge channel leading out of the upper chamber portion of the pressure manipulation chamber, the gas discharge channel including at least one second control valve structured for selective discharge of manipulation gas from the pressure manipulation chamber, and also for regulation of the pressure (Pchamber) of the gas therein; and

(A) directing manipulation gas out of the pressure manipulation chamber and also lowering the gas pressure (Pchamber) therein to a lower pressure (Plower) at which a resulting pressure difference (Psource-Plower) drives the liquid from the liquid source and into the pressure manipulation chamber via the liquid supply channel;

(B) filling the liquid up to an upper liquid level in the pressure manipulation chamber;

(C) directing manipulation gas into the pressure manipulation chamber and increasing the gas pressure (Pchamber) therein to an upper pressure (Pupper) at which a resulting pressure difference (Pupper-Preceiving) drives the liquid from the pressure manipulation chamber and onwards to the receiving region via said liquid discharge channel;

(D) driving the liquid down to a lower liquid level in the pressure manipulation chamber; and

(E) repeating steps (A)-(D), the course of which represents one operating cycle, thereby maintaining the pumping of liquid from the liquid source and onwards to the receiving region via the pressure manipulation chamber.

21. The method according to claim 20, wherein the method also comprises:

connecting said liquid supply channel in a flow-communicating manner to at least one water production formation connected to the well, the water production formation thus constituting said liquid source; and

connecting said liquid discharge channel in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for water emanating from the water production formation.

22. The method according to claim 20, wherein the method also comprises:

connecting said liquid supply channel in a flow-communicating manner to at least one oil production formation connected to the well, the oil production formation thus constituting said liquid source; and

connecting said liquid discharge channel in a flow-communicating manner to the surface of the well, the surface thus constituting the receiving region for oil emanating from the oil production formation.

23. The method according to claim 21, wherein the method also comprises:

using a gas discharge channel comprising at least one gas bleed channel and filling it with manipulation gas for selective discharge of lift gas into said liquid discharge channel, whereby a gas pressure gradient is present in the gas bleed channel, whereas a liquid pressure gradient is present in the liquid discharge channel;

by means of said gas bleed channel, connecting the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the liquid discharge channel where the liquid has a liquid pressure (Pshallower); and

selecting said shallower depth level at a depth where the liquid pressure (Pshallower), via the gas pressure gradient in the gas bleed channel, results in said lower gas pressure (Plower) in the pressure manipulation chamber, insofar as the lower gas pressure (Plower) is substantially smaller than a corresponding liquid pressure at the same level in the liquid discharge channel;

whereby the difference between the densities of the manipulation gas and the liquid is utilized to provide the lower gas pressure (Plower) in the pressure manipulation chamber; and

whereby the pumping device is structured to selectively direct manipulation gas into the liquid discharge channel as lift gas for the liquid.

24. The method according to claim 20, wherein said gas source is comprised of at least one of the following gas sources:

a gas source at the surface; and

a gas source in a subsurface formation.

25. The method according to claim 20, wherein the method also comprises:

connecting said liquid supply channel in a flow-communicating manner to a water-containing liquid in at least one hydrocarbon-water-separator located in the well, the separator constituting said liquid source;

wherein said separator is connected in a flow-communicating manner to a hydrocarbon- and water-containing production flow emanating from at least one production formation connected to the well; and

wherein the separator is structured so as to be able to at least separate said production flow into said water-containing liquid and into a hydrocarbon-containing liquid;

connecting the hydrocarbon-containing liquid in the separator in a flow-communicating manner to at least one production channel for production of the hydrocarbon-containing liquid; and

connecting said liquid discharge channel in a flow-communicating manner to at least one disposal formation connected to the well, the disposal formation constituting said receiving region for separated, water-containing liquid emanating from the separator.

26. The method according to claim 25, wherein the method also comprises:

using a gas discharge channel comprising at least one gas bleed channel and filling it with manipulation gas for selective discharge of lift gas into said production channel, whereby a gas pressure gradient is present in the gas bleed channel, whereas a liquid pressure gradient is present in the production channel;

by means of said gas bleed channel, connecting the upper chamber portion of the pressure manipulation chamber in a flow-communicating manner to a shallower depth level in the production channel where the hydrocarbon-containing liquid has a liquid pressure (Pshallower); and

selecting said shallower depth level at a depth where the liquid pressure (Pshallower), via the gas pressure gradient in the gas bleed channel, results in said lower gas pressure (Plower) in the pressure manipulation chamber, insofar as the lower gas pressure (Plower) is substantially smaller than a corresponding liquid pressure at the same level in the production channel;

whereby the difference between the densities of the manipulation gas and the hydrocarbon-containing liquid is utilized to provide the lower gas pressure (Plower) in the pressure manipulation chamber; and

whereby the pumping device is structured to selectively direct manipulation gas into the production channel as lift gas for the hydrocarbon-containing liquid.

27. The method according to claim 25, wherein said gas source is comprised of at least one of the following gas sources:

a gas source at the surface;

a gas source in a subsurface formation; and

a gas source in the form of gas separated from the hydrocarbon- and water-containing production flow emanating from said production formation.

28. The method according to claim 25, wherein said at least one hydrocarbon-water-separator comprises at least one cyclone separator.

29. The method according to claim 25, wherein said at least one hydrocarbon-water-separator comprises at least one gravity separator.

30. The method according to claim 29, further comprising the step of locating the gravity separator, which is comprised of a horizontal gravity separator, in a horizontal portion of the well.

31. The method according to claim 25, further comprising the step of locating the pressure manipulation chamber at a distance from the at least one separator.

32. The method according to claim 25, wherein the at least one disposal formation is situated shallower than the production formation.

33. The method according to claim 25, wherein the at least one disposal formation is situated deeper than the production formation.

34. The method according to claim 25, wherein the at least one disposal formation comprises at least one disposal layer in the production formation.

35. The method according to claim 20, further comprising the step of locating the pressure manipulation chamber in a pipe in the well.

36. The method according to claim 20, further comprising the step of locating the pressure manipulation chamber on the outside of a pipe in the well.

37. The method according to claim 20, further comprising the step of locating the pressure manipulation chamber in an annulus in the well.

38. The method according to claim 20, further comprising the steps of:

locating at least two of said pumping devices in the well, wherein each pumping device includes at least one pressure manipulation chamber;

structuring the pumping devices for cooperative pumping of liquid from said liquid source and onwards to said receiving region; and

arranging the pumping devices with a phase-lagged operating cycle relative to each other, whereby a smoother induction and pumping of liquid is achieved.

39. The method according to claim 37, further comprising the step of connecting at least two pumping devices in parallel.

40. The method according to claim 37, further comprising the step of connecting at least two pumping devices in series.