A combined injection and abstraction valve

Abstract

ion valve, for injecting fluid into, and abstracting fluid from, a subterranean reservoir, comprises a housing connectable between a riser and a pump, a sleeve slidingly retained completely within the housing, so as to be selectively movable relative to the housing between a first position, wherein the valve is in an injection mode for injecting fluid into the reservoir, and a second position, wherein the valve is in an abstraction mode for abstracting fluid from the reservoir, there being a cavity between the sleeve and the housing wall, which is divisible into first and second fluid-receiving chambers of adjustable volume, and a solid, flexibly resilient seal located between the chambers, whereby fluid from the first chamber is inhibited from filling the second chamber, wherein, when the first chamber is charged with fluid, the sleeve is driven from injection mode to abstraction mode.

Description

A Combined Injection and Abstraction ValveTECHNICAL FIELD

[0001] The present disclosure relates to a bi-directional valve for use in a borehole, and a fluid system incorporating such a valve. In particular, the disclosure relates to a valve which is used to control the flow of liquid being injected into and extracted from a subterranean reservoir, such as an aquifer, non-operational mineshaft and the like.BACKGROUND TO THE DISCLOSURE

[0002] Generally, borehole injection valves are used to control the amount of water being injected into a subterranean aquifer via a downpipe or riser installed within a borehole casing extending from ground level to the body of water concerned. The valve is typically located within the borehole casing at the lower end of the downpipe and at an optimum level relative to the depth of the subterranean aquifer. The valve is usually operated from the surface using a powered hydraulic system. The hydraulic system is connected to the valve to control operation of the valve. In order to vary the flow rate of water being injected, and depending on the valve type, the hydraulic system may operate a piston within a cylinder of the valve, cause sliding movement of a sleeve mounted on the outer periphery of the valve housing, or cause the inflation / deflation of a flexible tube within the valve housing.

[0003] Some boreholes have a requirement where abstraction of water is required in addition to injection of water. This requires a submersible electrically driven pump to be fitted to a lower end of the injection valve and it is this form of valve. Such a valve is referred to as a combined injection valve.

[0004] Current combined injection valves employ a hollow tube housing mounted on the lowest end of a borehole downpipe and have an electrically driven submersible pump mounted at the lower end of the housing. The submersible pumpis fitted with a non-return valve to prevent water entering the pump during injection. The housing employs a sliding sleeve which is externally mounted and hydraulically operated. This sleeve progressively exposes or covers a number of openings provided in the valve housing wall, allowing the flow of water into the aquifer to be controlled when water is being injected therein. When abstraction of water from the aquifer is required, the sleeve is positioned to cover the openings, and the submersible pump directs water through the valve and up the downpipe to the surface. Within this valve, the sleeve is caused to slide by means of a separate powered hydraulic system located at ground level. This system uses oil as the operating medium and requires a power supply.

[0005] As many boreholes and aquifers are in remote locations, regular maintenance of the powered hydraulic system is often a logistical challenge. Also, environmental regulations prohibit contamination of any kind within pristine aquifers, thereby prohibiting the use of oil operated equipment. In addition, these systems require an electric cable that is supported by the borehole downpipe to supply power for the submersible pump. This cable passes over and adjacent to the sliding sleeve thereby presenting a potential for wearing / abrasion of the cable by the reciprocating action of the sleeve and can result in electrical failure.

[0006] US Patent Application Publication No. 2010 / 0213396 describes a valve for injection and abstraction of water from an underground aquifer. The valve provides a sliding piston-like sleeve on the outside of a water abstraction or injection pipe. The sleeve is exposed to the operational risks identified in the previous paragraph.

[0007] Within the systems employing dual acting valves of the kind disclosed in Australian patent application 2022291528, from which this present application derives, there is an issue with potential bleeding of working fluid between portions of the chamber into which the working fluid is injected under pressure to cause the valve mechanism to change from injection to abstraction condition (or mode). The bleeding of working fluid impacts negatively on efficiency of operation and energy usage.

[0008] Furthermore, boreholes commonly gather surface debris for a variety of reasons which can become wedged between the sliding sleeve and the borehole casing resulting in jamming of the sleeve, and malfunction of the valve.

[0009] The preceding discussion of background art is intended to facilitate an understanding of the present disclosure only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0010] It is an object of the invention herein disclosed to provide a combined valve and a fluid system which ameliorates, mitigates or overcomes, at least one disadvantage of the prior art.

[0011] Throughout this specification, the term ‘reservoir’ is used to describe a subterranean body of fluid, such as water, within an aquifer, mineshaft, tank or other container.

[0012] Throughout this specification the term ‘borehole’ is used to describe any passageway, conduit, pipe, channel or similar pathway extending from a reservoir to an alternative location, such as a dam.SUMMARY OF INVENTION

[0013] According to the invention in a first aspect, there is provided a combined injection valve adapted to inject fluid into, and abstract fluid from, a reservoir via a downpipe or riser, the valve comprising:a housing having a first end adapted to be secured to a riser, and a second end adapted for fluid communication with a pump;a sleeve slidingly retained entirely within the housing, the sleeve being movable relative to the housing between a first position, wherein the valve is in an injection mode for injecting fluid into the reservoir, and a second position, wherein the valve is in an abstraction mode for abstracting fluid from the reservoir and discharging the fluid into the riser,first and second chambers of adjustable respective volumes located between the housing and the sleeve, selective adjustment of said volumes causing selective movement of the sleeve relative to the housing between said first and second positions;wherein said first and second chambers are fluid-sealingly isolated from each other by solid fluid sealing means interposed between them.

[0014] The chambers in an embodiment are sealed from the valve passage.

[0015] In an embodiment, the first and second chambers are defined within an annular space surrounding the sleeve.

[0016] The annular space preferably comprises an annular recess formed in an internal wall surface of the housing, and into which recess a radially projecting outer portion of the sleeve is receivable.

[0017] In an embodiment, the chambers are separated by first and second annular rings extending radially in spaced relationship from an outer surface of the sleeve, and between which rings the solid fluid sealing means is interposed.

[0018] The solid fluid sealing means may comprise a resiliently flexible ring that operatively bears against an inner surface of the housing and an outer surface of the sleeve, thereby presenting a substantially impenetrable barrier to fluid entering a space between said surfaces.

[0019] In an embodiment, the housing and sleeve co-operate to define a valve passage through the valve, the passage extending from the first end to the second end.

[0020] In an embodiment, the housing includes one or more openings defining water injection outlets adjacent the second end of the valve, the one or more outlets being in fluid communication with the valve passage when the valve is in the injection mode and not being in fluid communication with the valve passage when the valve is in abstraction mode.

[0021] In a second aspect of the invention, a combined injection valve comprises an outer housing including a round cylindrical wall defining a hollow internal space, within which space a sleeve is slidably installed, selectively to cover or uncover, by sliding within said space and along said wall, a fluid outlet opening in the housing wall, the sleeve defining an internal fluid conduit in fluid communication with a riser and a pump, the sleeve having an outer surface from which a plurality of annular rings extend outwardly to maintain an annular chamber between an outer surface of the sleeve and the inner surface of the housing wall, wherein a first of the annular rings divides the chamber into first and second annular chamber portions within said annular space, said portions being of adjustable volume, and wherein the first annular ring includes a solid sealing ring selected for substantially preventing fluid communication between said chamber portions.

[0022] In an embodiment, the first chamber portion is locatable proximate to the riser, and is adapted to receive a working fluid therefrom, while the second portion of the chamber is locatable proximate the pump, and is adapted to discharge a working fluid therefrom, the receiving and simultaneous discharging of the working fluid causing the first annular ring and sealing ring to be displaced toward the pump, thereby closing the fluid outlet opening in the housing wall.

[0023] In a third aspect of the invention, there is provided a combined injection valve operable in a first mode for injecting fluid into, and in a second mode for abstracting fluid from, a reservoir, the valve comprising:a hollow housing having a channel therethrough, the channel having a portion with a cylindrical inner surface of constant inner diameter,a sleeve slidingly received in the channel, the sleeve having an outer surface from which an upper ring and a lower ring outwardly extend, each ring having an outer diameter smaller than the inner diameter of the channel portion;the housing and sleeve co-operating to definea passage through which fluid passes, the housing having an outlet which forms part of the valve passage when the valve is in injection mode; andan annular chamber adapted to receive or discharge a working fluid for moving the sleeve relative to the housing,the annular chamber including upper and lower portions of selectively adjustable volume for receiving the working fluid and an intermediate portion retaining a solid sealing ring effective to substantially isolate the upper and lower portions from fluid communication between them,wherein the sleeve is movable relative to the housing betweena first position representing injection mode, wherein the lower chamber portion is charged with working fluid, and the upper chamber portion is substantially devoid of working fluid, anda second position representing abstraction mode, wherein the lower chamber portion is substantially devoid of working fluid and the upper chamber portion is charged with working fluid, for abstracting fluid from the reservoir.

[0024] In an embodiment, the housing includes a first end adapted to be secured to a riser, and a second end adapted to be secured to a pump.

[0025] In an embodiment, the inner surface of the channel portion, an external surface of the sleeve and the upper and lower rings define the annular chamber.

[0026] The annular chamber is preferably sealingly isolated from the valve passage.

[0027] The valve is preferably adapted to allow connection of a first fluid line to establish fluid communication for working fluid with the upper chamber portion and of a second fluid line to establish fluid communication for working fluid with the lower chamber portion.

[0028] In a third aspect of the invention, there is provided a combined injection valve comprising:a. a hollow cylindrical body shaped for installation in a borehole casing, the body having a side wall with an outlet for water passage, a first end connectable to a riser and a second end connectable to a pump,b. a water conduit extending within the body from end to end to define a passage for water to pass axially through the body and to the opening,c. an opening in the conduit aligned with the outlet in the sidewall through which water is injected in use to a reservoir, andd. a moveable sleeve housed entirely within the body and surrounding the conduit, the body having an internal formation and the sleeve having an external formation displaceable relative to said internal formation, said formations being separated by a fluid seal of a resilient, solid material, and the formations being configured for reciprocal displacement relative to each other under hydraulic actuation by a working fluid causing displacement of the sleeve from a first position in which it covers the opening to a second position in which the opening is uncovered for allowing injection of water into the reservoir.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:Figure 1 is a schematic depiction of a fluid system according to a first embodiment of the present invention;Figure 2 is a cross-sectional side view of a valve shown in Figure 1 , the valve being in injection mode;Figure 3 depicts the valve of Figure 2 in abstraction mode;Figure 4 includes views of a preferred embodiment of the valve in abstraction mode, where (a) is a side view; (b) is a cross-section taken along line A-A in (a); and (c) is a detail view of the encircled call-out portion ‘B’ in (b).Figure 5 provides views of the embodiment of Figure 4, now in injection mode, where (a) is a side view; (b) is a cross-section taken along line C-C in (a); and (c) is a detail view of the encircled call-out portion ‘D’ in (b).

[0030] In the drawings like structures are referred to by like numerals throughout the several views, where suitable. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.DESCRIPTION OF EMBODIMENTS

[0031] In a first embodiment of the present invention, there is provided a combined injection valve which is used to control the flow of liquid, such as water, as it is injected into a borehole for the purpose of recharging a subterranean reservoir or aquifer. The valve is also designed to perform the abstraction of the liquid from the reservoir water, wherein the valve is operable selectively to alternate between injection and abstraction modes.

[0032] With reference to Figure 1 , fluid a system for fluid to be injected into or abstracted from a reservoir is depicted. So that these opposite operations may take place, a borehole 11 is first drilled through to a reservoir 13 before a borehole casing 15 is installed in the borehole 11. A fluid system 17, according to an embodiment of the present invention, may then be installed for injecting and abstracting fluid from reservoir 13.

[0033] Fluid system 17 comprises a valve 19, a first pipe, in the form of a riser21, secured to a first end 23 of the valve 19, a pump 25 secured to a second end 27 of the valve 19, and control means for operating the valve. Riser 21 is secured via a bore-head 29 to headworks 31, through which fluid passes when either injecting fluid into, or abstracting fluid from reservoir 13.

[0034] The configuration of valve 19 is shown in Figures 2 and 3. Figure 2 represents valve 19 in injection mode. In injection mode, fluid can be injected into reservoir 13. The flow of fluid through valve 19 when in injection mode is indicated by arrows “A”. Figure 3 represents valve 19 when in abstraction mode. In abstraction mode, fluid can be abstracted from the reservoir 13. The flow of fluid through valve 19 when in the abstraction mode is indicated by arrows “B”.

[0035] Valve 19 comprises a housing 33 and a sleeve 35 slidingly retained in the housing 33. In this embodiment, both housing 33 and sleeve 35 are coaxially arranged, hollow and tubular in shape, and co-operate to define a valve passage 37 extending between end 23 and end 27 as shown in Figure 1. Passage 37 is open at both ends, allowing unimpeded fluid flow between them when the valve is in abstraction mode.

[0036] Housing 33 also includes an annular channel 39, which has an inner wall section presenting a substantially continuous surface 43, along which sleeve 35 slides.

[0037] The inner surface 43 of channel 39 co-operates with the outer surface 49 of sleeve 35 to define a chamber 51. By means of fluid sealing rings 53, chamber 51 is sealed against fluid passage relative to valve passage 37. Sealing rings 53 are located in upper annular sealing grooves 54, 56, which are formed in an inner circumferential surface of an upper seal carrier portion 24, and in lower annular sealing grooves 64, 66, which are formed in an inner circumferential surface of an upper seal carrier portion 28. Carrier portions 24, 28 are integrally formed with ends 23 and 27 respectively and are fixed to housing 33 in fluid sealing relationship. The carrier portions may be fixed by mechanical means such as screw threads or by chemical means such as water- and hydraulic pressure-tolerant adhesives well known in the art. The configuration and size of chamber 51 change according tothe mode of valve operation, as will be described below.

[0038] Sleeve 35 has an upper collar / ring 45 and a lower collar / ring 47 in spaced relation to each other. These extend outwardly from an outer surface 49 of sleeve 35 into chamber 51. Each ring 45, 47 has an outer diameter slightly smaller than the internal diameter of channel 39 and divides chamber 51 into three portions: An upper chamber portion 55, a lower chamber portion 57, and an intermediate chamber portion 59 of fixed volume. Chamber 59 is substantially occupied by a sealing ring 60, which provides a fluid seal between upper chamber 55 and lower chamber 57. Ring 60 is made from a resiliently flexible rubber-like material, nonlimiting examples including synthetic compounds well known in the sealing art, such as nitrile. Natural rubber may also be utilized.

[0039] The respective volumes of upper chamber portion 55 and lower chamber portion 57 are adjustably variable as a result of movement of sleeve 35 relative to housing 33. Variable upper chamber portion 55 is defined by that portion of the chamber above upper ring 45 of the sleeve, while the variable lower chamber portion 57 is defined by that portion of the chamber below lower ring 47 of sleeve 35. Intermediate chamber portion 59 is defined by that portion of chamber 51 that is located between upper ring 45 and lower ring 47.

[0040] The volume of upper chamber portion 55 varies between zero volume, as shown in Figure 2, and its maximum volume, as shown in Figure 3, whereas the volume of lower chamber portion 57 varies between its maximum volume, as shown in F igure 2, and zero volume, as shown in Figure 3.

[0041] Although the volume of intermediate chamber portion 59 is fixed, this chamber portion itself, together with sealing ring 60 in place, undergoes displacement along the inner wall surface 43 of channel 39 within housing 33. Displacement is by virtue of the working fluid filling and being expelled from adjustable chamber portions 55, 57 according to operating mode.

[0042] The presence of sealing ring 60, occupying intermediate chamber portion 59, improves performance of valve 19 by helping maintain a distinct volumeof working fluid in each of the upper and lower chamber portions 55, 57. This enables sleeve 35 to be effectively locked in place, once it has been displaced to its desired position for the operational mode being selected, namely abstraction or injection. In this way, the sealing ring substantially prevents fluid leakage from whichever of the adjustable upper and lower chambers is being filled with pressurized fluid to cause the mode change from abstraction to injection. Stopping such leakage improves efficiency of working fluid use by greatly reducing the amount of working fluid required to charge up the chamber undergoing charging and, by the same token, reducing the amount of working fluid that needs to be expelled from the chamber being emptied so that it can achieve its minimum or zero volume. Moreover, the nature of the sealing performance provided by the flexibly resilient sealing ring allows for substantially higher operational pressures to be achieved, as the internal pressure in the sleeve is essentially pushing the seal against the sealing surface.

[0043] Housing 33 has a series of outlets 61 adjacent the second end 27 of the valve. These outlets 61 extend through the wall of housing 33 from the channel to an outer surface 63 of housing 33.

[0044] The control means for adjusting the respective volumes of chamber portions 55, 57 comprises a control apparatus (not shown) which selectively operates solenoids (not shown) to regulate a working fluid 65 into and out of chamber 51 to selectively move sleeve 35 relative to housing 33. The control means also comprises a first fluid line 67, which is in fluid communication with the upper chamber portion 55, and a second fluid line 69, which is in fluid communication with the lower chamber portion 57. Co-ordinated movement of the working fluid through first fluid line 67 and second fluid line 69 causes movement of sleeve 35 relative to housing 33.

[0045] In operation, when working fluid 65 is injected into the upper chamber portion 55 through the first fluid line 67, sleeve 35 is caused to move downwardly, increasing the volume of upper chamber portion 55. As sleeve 35 moves downwardly, a bottom portion 71 of the sleeve starts to obstruct and close outlets 61in housing 33. Working fluid 65 in lower chamber portion 57 is caused to exit therefrom through the second fluid line 69, and the volume of the lower chamber decreases. Sealing ring 60 helps improve operation by inhibiting bleeding of working fluid 65 from upper chamber portion 55 to lower portion 57 while the upper portion is being charged under pressure and the lower portion is being emptied. Eventually the bottom portion 71 of sleeve 35 completely closes each outlet 61. When the sleeve is in this position, valve 19 is in abstraction mode, ready for pump 25 to be energized, so that fluid can be abstracted from reservoir 13.

[0046] To change valve 19 from the abstraction mode to injection mode, the reverse process takes place. Working fluid 65 is injected into lower chamber portion 57 through the second fluid line 69. This causes sleeve 35 and bottom portion 71 to move upwardly, increasing the volume of lower chamber portion 57, and removing the obstruction covering outlets 61 so that they are open. During this process, the working fluid in upper chamber portion 55 is expelled therefrom through first fluid line 67, resulting in a decrease in the volume of upper chamber portion 55. With outlets 61 open, fluid can be injected into the reservoir through valve 19.

[0047] A valve according to a preferred embodiment of the invention is illustrated in F igures 4 and 5 and is labelled 10.

[0048] Figure 4 illustrates a modified version of the valve of the embodiment of Figures 2 and 3. Like parts encountered in the previous figures are allocated like numbering. The modification pertains to the inclusion of a sealing ring 60, which is located in intermediate fixed volume chamber 59, described in relation to the previous figures. The presence of ring 60 improves valve performance by providing an enhanced barrier to fluid leakage between the variable-volume chambers 55, 57.

[0049] The exterior of the valve is depicted in Figure 4(a). Figure 4(b) is a section taken on line A-A of (a) and represents valve 10 in abstraction mode, in which injection ports 61 are closed. Figure 4(c) is a detail callout B, taken from the portion of Figure 4(b) enclosed by the oval bounded zone labeled B. Figure 5 illustrates the valve of Figure 4 In injection mode, where fluid can be injected into reservoir 13 via ports 61. Figure 5(b) is a section taken on line C-C of Figure 5(a) and Figure 5(c) is detailedillustration of the portion of Figure 5(b) enclosed by the oval bounded zone labelled D.

[0050] As in the previous figures, valve 10 comprises a housing 33, and a sleeve 35 slidingly retained in its entirety within said housing. In this embodiment, both housing 33 and sleeve 35 are hollow and round-cylindrical in shape, and co-operate to define a cylindrical valve passage 37 of circular profile, through which water is abstracted or injected according to the selected mode of operation, namely injection or abstraction.

[0051] Housing 33 has a first end 23 and a second end 27, between which extends an annular channel 39. Housing 33 is connected to upper 24 and lower 28 seal carrier portions, by means of screw threaded connection formations 30. Channel 39 is bounded by the exterior surface 49 of sleeve 35 and the inner wall surface 43 of housing 33, along and adjacent to which sleeve 35 slides. Sliding motion is aided by a film 52 of working fluid from the annular chamber 51, which infiltrates a narrow space 54 between the outer surface 49 of sleeve 35 and the surfaces with which it comes into close proximity and abutment, as will be described below.

[0052] Projecting from outer surface 49 of sleeve 35 are an upper ring defining a collar 45 and a lower ring defining a collar 47. The collars lie in a spaced axial relationship with each other and extend outwardly from sleeve outer surface 49 into chamber 51. Each collar 45, 47 has an outer diameter slightly smaller than the internal diameter of channel 39 and divides chamber 51 into three interleading portions as in the embodiment of Figures 2 and 3, these chamber portions being an upper chamber portion 55, a lower chamber portion 57, and an intermediate chamber portion 59. Portion 59 is of fixed volume, whereas the respective volumes of upper chamber portion 55 and lower chamber portion 57 are adjustably variable. Volume adjustment is by virtue of controllable movement of sleeve 35 relative to housing 33.

[0053] Chamber 51 is hydraulically sealed and isolated against fluid ingress from valve passage 37 by means of a plurality of spaced apart sealing rings 53.

[0054] Variable upper chamber portion 55 is defined by that portion of combined chamber 51 which is located above upper ring 45 of the sleeve, the term“above” denoting the fact that the chamber is to the riser side of ring 45, or in the direction of upper end 23 of the valve.

[0055] Variable lower chamber portion 57 is defined by that portion of the chamber which is located below lower ring 47 of sleeve 35. The term “lower” refers to the chamber being to the pump side of ring 47, or in the direction of lower end 27 of the valve.

[0056] Intermediate chamber portion 59 is defined by that portion of chamber 51 that is located between upper ring 45 and lower ring 47.

[0057] The volume of upper chamber portion 55 varies between a minimal or “zero” volume, as depicted in Figure 5, and its maximum volume, as shown in Figure 4, whereas the volume of lower chamber portion 57 varies between its minimal or “zero” volume, as shown in F igure 4 , and a maximum volume shown in Figure 5. Reference may be made to the discussion of Figures 2 and 3 in relation to the first embodiment described above.

[0058] Housing 33 has a series of outlets 61 adjacent the second end 27 of the valve. These outlets 61 extend through the wall of housing 33 from the channel to an outer surface 63 of housing 33.

[0059] Adjustment of the respective volumes of chamber portions 55, 57 is via a control apparatus (not shown) of the kind described in relation to Figures 2 and 3. The control apparatus is operable to regulate the flow of a working fluid into and out of chamber 51, thereby to selectively move sleeve 35 relative to housing 33 in a reciprocating manner.

[0060] The control apparatus comprises a first fluid line connectable at connection point 67, which is in fluid communication with the upper chamber portion 55, and a second fluid line connectable at connection point 69, which is in fluid communication with the lower chamber portion 57. Co-ordinated flow movement of the working fluid through first fluid line connection 67 and second fluid line connection 69 causes movement of sleeve 35 relative to housing 33. The result is that when chamber portion 55 is being charged with working fluid via connection point 67,working fluid is being extracted from chamber portion 57 via connection point 69, and vice versa.

[0061] While chamber portion 55 is being filled with the working fluid, sleeve 35 is forced to move towards end 27 of the valve, with its lower end portion 71 closing off fluid discharge ports 61 to fluid communication with passage 37, and placing the valve in abstraction mode. To achieve injection mode, working fluid is forced into lower chamber portion 57 while fluid is allowed to escape from upper chamber portion 55 via line connection 67. This enables sleeve 35 to move toward end 23 of the valve, causing lower end 71 to uncover discharge ports 61 in the process, so that water flowing into the valve from the ground surface or other superior level will escape through the ports into the waiting reservoir.

[0062] As working fluid 65 in lower chamber portion 57 is caused to exit therefrom through the second fluid line 69, the volume of lower chamber portion 57 decreases. Eventually the bottom portion 71 of sleeve 35 completely closes each outlet port 61. When the sleeve is in this position, valve 10 is in abstraction mode, ready for pump 25 (in Figure 1) to be energized, for fluid abstraction from the reservoir.

[0063] To change valve 10 from the abstraction mode to injection mode, the reverse process takes place, as illustrated in Figure 5. Working fluid 65 is injected into lower chamber portion 57 through the second fluid line connection point 69. This causes sleeve 35 and bottom portion 71 to move upwardly towards end 23, thereby increasing the volume of lower chamber portion 57, and removing the obstruction 72, defined by bottom portion 71, from covering outlets 61 so that they are open. During this process, the working fluid in upper chamber portion 55 is expelled therefrom, through the first fluid line connection point 67, diminishing the volume of upper chamber portion 55. With outlets 61 open, fluid can be injected into the reservoir through valve 10.

[0064] The improvement introduced to the embodiments described herein by the presence of annular sealing ring 69 to define a sealed intermediate chamber 59.

[0065] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The presentdisclosure is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the disclosure as described herein.

[0066] Terminology used herein is for describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprise”, “comprises,” “comprising,” “including,” and “having,” or variations thereof are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0067] The operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0068] Reference to positional descriptions, such as lower and upper, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the scope of this disclosure to the literal interpretation of the term in question, but rather as it would be understood by the skilled addressee.

[0069] When a feature or component is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another feature or component, it may be directly on, or engaged, connected or coupled to the other feature or component, or an intervening feature or component may be present. By contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another feature or component, there may be no intervening feature or component present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc..). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

Claims

CLAIMS1. A combined injection valve adapted to inject fluid into, and abstract fluid from, a reservoir via a downpipe or riser, the valve comprising:a housing having a first end adapted to be secured to a riser, and a second end adapted for fluid communication with a pump;a sleeve slidingly retained entirely within the housing, the sleeve being movable relative to the housing between a first position, wherein the valve is in an injection mode for injecting fluid into the reservoir, and a second position, wherein the valve is in an abstraction mode for abstracting fluid from the reservoir and discharging the fluid into the riser,first and second chambers of adjustable respective volumes located between the housing and the sleeve, selective adjustment of said volumes causing selective movement of the sleeve relative to the housing between said first and second positions;wherein said first and second chambers are fluid-sealing ly isolated from each other by solid fluid sealing means interposed between them.

2. The valve of claim 1, wherein the chambers are sealed from the valve passage.

3. The valve of claim 1 or claim 2, wherein the first and second chambers are defined within an annular space surrounding the sleeve.

4. The valve of claim 3, wherein the annular space comprises an annular recess formed in an internal wall surface of the housing, and into which recess a radially projecting outer portion of the sleeve is receivable.

5. The valve of claim 4, wherein the chambers are separated by first and second annular rings extending radially in spaced relationship from an outer surface of the sleeve, and between which rings the solid fluid sealing means is interposed.

6. The valve of claim 5, wherein the solid fluid sealing means comprises a resiliently flexible ring that operatively bears against an inner surface of the housing and an outer surface of the sleeve, thereby presenting a substantially impenetrable barrier to fluid entering a space between said surfaces.

7. The valve of claim 6, wherein the housing and sleeve co-operate to define a valve passage through the valve, the passage extending from the first end to the second end.

8. The valve of claim 7, wherein the housing includes one or more openings defining water injection outlets adjacent the second end of the valve, the one or more outlets being in fluid communication with the valve passage when the valve is in the injection mode and not being in fluid communication with the valve passage when the valve is in abstraction mode.

9. A combined injection valve comprising an outer housing including a round cylindrical wall defining a hollow internal space, within which space a sleeve is slidably installed, selectively to cover or uncover, by sliding within said space and along said wall, a fluid outlet opening in the housing wall, the sleeve defining an internal fluid conduit in fluid communication with a riser and a pump, the sleeve having an outer surface from which a plurality of annular rings extend outwardly to maintain an annular chamber between an outer surface of the sleeve and the inner surface of the housing wall, wherein a first of the annular rings divides the chamber into first and second annular chamber portions within said annular space, said portions being of adjustable volume, and wherein the first annular ring includes a solid sealing ring selected for substantially preventing fluid communication between said chamber portions.

10. The valve of claim 9, wherein the first chamber portion is locatable proximate to the riser, and is adapted to receive a working fluid therefrom, while the second portion of the chamber is locatable proximate the pump, and is adapted to discharge a working fluid therefrom, the receiving and simultaneous discharging of the working fluid causing the first annular ring and sealing ring to be displaced toward the pump, thereby closing the fluid outlet opening in the housing wall.

11. A combined injection valve operable in a first m ode for injecting fluid into, and in a second mode for abstracting fluid from, a reservoir, the valve comprising:a hollow housing having a channel therethrough, the channel having a portion with a cylindrical inner surface of constant inner diameter,a sleeve slidingly received in the channel, the sleeve having an outer surface from which an upper ring and a lower ring outwardly extend, each ring having an outer diameter smaller than the inner diameter of the channel portion;the housing and sleeve co-operating to definea passage through which fluid passes, the housing having an outlet which forms part of the valve passage when the valve is in injection mode; andan annular chamber adapted to receive or discharge a working fluid for moving the sleeve relative to the housing,the annular chamber including upper and lower portions of selectively adjustable volume for receiving the working fluid, and an intermediate portion retaining a solid sealing ring effective to substantially isolate the upper and lower portions from fluid communication between them,wherein the sleeve is movable relative to the housing betweena first position representing injection mode, wherein the lower chamber portion is charged with working fluid and the upper chamber portion is substantially devoid of working fluid, anda second position representing abstraction mode, wherein the lower chamber portion is substantially devoid of working fluid and the upper chamber portion is charged with working fluid, for abstracting fluid from the reservoir.

12. The valve of claim 11 , wherein the housing includes a first end adapted to besecured to a riser, and a second end adapted to be secured to a pump.

13. The valve of claim 11 or claim 12, wherein the cylindrical inner surface of the channel portion, an external surface of the sleeve, and the upper and lower rings define the annular chamber.

14. The valve of claim 13, wherein the annular chamber is sealingly isolated from the valve passage.

15. A valve according to any one of claims 11 to 14, wherein the valve is adapted to allow connection of a first fluid line to establish fluid communication for working fluid with the upper chamber portion and of a second fluid line to establish fluid communication for working fluid with the lower chamber portion.

16. A combined injection valve comprising:a. a hollow cylindrical body shaped for installation in a borehole casing, the body having a side wall with an outlet for water passage, a first end connectable to a riser and a second end connectable to a pump,b. a water conduit extending within the body from end to end to define a passage for water to pass axially through the body and to the opening,c. an opening in the conduit aligned with the outlet in the sidewall through which water is injected in use to a reservoir, andd. a moveable sleeve housed entirely within the body and surrounding the conduit, the body having an internal formation and the sleeve having an external formation displaceable relative to said internal formation, said formations being separated by a fluid seal of a resilient, solid material, and the formations being configured for reciprocal displacement relative to each other under hydraulic actuation by a working fluid causing displacement of the sleeve from a first position in which it covers the opening to a second position in which the opening is uncovered for allowing injection of water into the reservoir.

17. The valve of claim 16, wherein the internal formation of the body defines a recess in the side wall and the external formation of the sleeve projects into the recess.

18. The valve of claim 17, wherein the recess is annular and the external formation of the sleeve comprises a collar.

19. The valve of claim 18, wherein the solid fluid seal comprises a circumferentially disposed sealing ring operatively establishing a fluid seal between the collar and the side wall within the recess.

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