Remote open sliding sleeve valve assembly

Abstract

Systems and methods for remotely opening valve assemblies for subterranean wells are described. The systems include a remote open valve assembly having a pressure-sensitive sleeve movable within a housing, and a first chamber, second chamber and third chamber all disposed between the housing and the pressure-sensitive sleeve and used to create a piston action to move the pressure-sensitive sleeve from an armed position to a shifted position. The movement of the pressure-sensitive sleeve is controlled using pressure events. The methods include shifting the pressure-sensitive sleeve to an armed position to open the first chamber, injecting fluid to fill the first chamber, increasing fluid pressure to unlock a valve to the second chamber, and decreasing fluid pressure to open the valve to the second chamber to allow it to fill with fluid, wherein upon reaching a threshold pressure in the second chamber, the pressure-sensitive sleeve shifts to an open position.

Description

Remote Open Sliding Sleeve Valve Assembly TECHNICAL FIELD

[0001] The disclosure relates to downhole tools for subterranean wellbore operations, and more specifically to valve assemblies that can be remotely opened using one or more pressure events.BACKGROUND

[0002] In subterranean wellbore operations, valve assemblies are commonly used to control access to the formation at different stages along the length of the wellbore during various operations, including for example fracturing, production, or injection. Valve assemblies have been described that include one or more sliding sleeves that can be shifted within a housing to various positions, the various positions generally effecting access through one or more ports in the housing through axial alignment or misalignment of the sleeve in relation to the one or more ports.

[0003] There are several ways for shifting a sliding sleeve, including running a downhole tool from the surface and into the wellbore to the target location, the downhole tool attached to jointed pipe, coiled tubing, wireline, or other means of conveyance. Running a downhole tool into a well to shift a sleeve can be time consuming and costly, particularly for difficult to access well locations such as offshore wells, and onshore wells in remote locations and / or challenging terrain, and / or during challenging weather conditions or seasonal windows.

[0004] Well completions may include lowering a casing string comprising one or more valve assemblies into a drilled well, followed by zonal isolation, typically achieved by cementing or using annular packers. For fracturing, a downhole tool, starting from the toe of the well and moving uphole, locateshin a valve assembly, shifts the sleeve to open the ports, fracturing fluid is injected through ports into the reservoir, the downhole tool shifts the sleeve to close the ports, then is moved uphole to the next sleeve so the process can repeat. This is commonly known in the art as a shift-frac-close process and requires a rig for raising and lowering the downhole tool into the well.

[0005] A drawback for the next phase relates to delays before production can be initiated. Some delays are inevitable, lasting anywhere from a week to several months, such as for installation of the necessary production equipment at the surface or on the seabed for offshore wells, but delays due to scheduling for bringing a rig to the site are unpredictable and may extend weeks or even months ahead. For offshore wells, the delays in bringing the rig via a drillship or Riserless Light Well Intervention (RLWI) vessel, are not only unpredictable and lengthy, but are also extremely cost extensive.

[0006] There is a need for alternative systems and methods for reopening sliding sleeve valve assemblies that are less expensive and time-consuming. Described herein is a remote open sliding sleeve valve assembly that can be opened using a pressure event, eliminating the need and cost for running a downhole tool into the well to reopen the sleeve.SUMMARY

[0007] According to the disclosure, there is provided a remote open valve assembly for integration within a wellbore string disposed within a subterranean formation, comprising a housing comprising a tubular wall defining a central passage therethrough and at least one port extending through the tubular wall; a pressure-sensitive sleeve longitudinally slidable within the housing between a position where the pressure-sensitive sleeve is axially aligned with the at least one port and a position where the pressuresensitive sleeve is axially misaligned with the at least one port, wherein the pressuresensitive sleeve may be shifted from the axially aligned position to the axially misaligned position by operation of opposing pistons within an annulus between the pressuresensitive sleeve and the housing, and without the use of a downhole tool.

[0008] The pressure-sensitive sleeve may be shifted to the axially misaligned position by dropping the pressure within the central passage.

[0009] The remote open valve assembly may further comprise a first chamber disposed between the housing and the pressure-sensitive sleeve and having a first piston area, a second chamber disposed between the housing and the pressure-sensitive sleeve and positioned between the first chamber and the at least one port along a longitudinal axis of the remote open valve assembly, and having a second piston area, the second piston area greater than the first piston area, a third chamber disposed between thehousing and the pressure-sensitive sleeve, and positioned between the first and second chambers along a longitudinal axis of the remote open valve assembly, a fluid pathway connecting the first chamber to the second chamber, the fluid pathway controlled by a valve to the second chamber, the valve changeable from a locked closed position wherein the valve cannot be opened, and fluid flow is prevented between the first chamber and the second chamber, to an unlocked closed position wherein the valve is closed but openable, and fluid flow is prevented between the first and second chamber; and to an unlocked open position wherein fluid flow can occur between the first chamber and the second chamber.

[0010] The valve may be kept in a locked position by retaining means.

[0011] The valve may be a spool valve, and the retaining means may comprise a spring pin mechanism or a j-track configuration.

[0012] The remote open valve assembly may further comprise a biasing means for driving the spool valve to the unlocked open position, and the biasing means may comprise a spring stack disposed radially around the pressure-sensitive sleeve and within the second chamber.

[0013] The spool valve may be converted to the unlocked closed position by defeating the retaining means in response to increasing the pressure in the first chamber to where the force applied to the spool valve by the pressure in the first chamber exceeds the force applied to the spool valve by the biasing means.

[0014] The spool valve may be converted to the unlocked open position by decreasing the pressure in the first chamber to where the force applied to the spool valve by the biasing means exceeds the force applied by pressure in the first chamber.

[0015] Converting the spool valve to the unlocked open position allows fluid to pass through the spool valve, allowing fluid communication, via the fluid pathway, between the first and second chambers, filling the second chamber, resulting in shifting, due to the second piston area being greater than the first piston area, of the pressure-sensitive sleeve away from the at least one port, allowing fluid within the central passage to move through the at least one port and into the subterranean formation.

[0016] The pressure-sensitive sleeve may progress from an armed configuration, wherein the pressure-sensitive sleeve is axially aligned with the at least one port and the first chamber is filled with fluid, to an unlocked closed configuration, wherein the pressuresensitive sleeve is axially aligned with the at least one port, the first chamber and the fluid pathway are filled with fluid, and the valve is in the unlocked closed position, and finally to a shifted configuration, wherein the pressure-sensitive sleeve is axially misaligned with the at least one port, and the first chamber, fluid pathway, and second chamber are fluid filled.

[0017] The pressure-sensitive sleeve may also be present in a sealed configuration prior to the armed configuration, where the pressure-sensitive sleeve is misaligned from the at least one port and the first chamber is not fluid filled.

[0018] The remote open valve assembly may further comprise a barrier device within the fluid pathway disposed between the first chamber and the valve, the barrier device required to be defeated by increasing pressure above a burst threshold before the pressure-sensitive sleeve progresses from the armed configuration to the unlocked closed position.

[0019] The remote open valve assembly may further comprise a functional region, disposed within the at least one port or as an extension of the pressure-sensitive sleeve, where shifting the pressure-sensitive sleeve to the axially misaligned position comprises shifting the functional region into an axially aligned position relative to the at least one port.

[0020] The functional region is selected from one or more of a screen, a check valve, an inflow control device, and a barrier device.

[0021] According to the disclosure, there is provided a remote open valve assembly for integration within a casing string disposed in a subterranean formation, comprising a housing comprising a tubular wall defining a central passage therethrough and at least one port extending through the tubular wall, a pressure-sensitive sleeve longitudinally slidable within the housing between a position where the pressure-sensitive sleeve is axially aligned with the at least one port and a position where the pressure-sensitive sleeve is axially misaligned with the at least one port, a first chamber disposed between the housing and the pressure-sensitive sleeve and having a first piston area, wherein when the pressure-sensitive sleeve is in a sealed position, fluid flow is prevented between thecentral passage and the first chamber, and when the pressure-sensitive sleeve is in an armed position, the first chamber is in fluid connection with the central passage, a second chamber disposed between the housing and the pressure-sensitive sleeve and positioned between the first chamber and the at least one port along a longitudinal axis of the remote open valve assembly, and having a second piston area, the second piston area greater than the first piston area, a third chamber disposed between the housing and the pressuresensitive sleeve, and positioned between the first and second chambers along a longitudinal axis of the remote open valve assembly, a fluid pathway connecting the first chamber to the second chamber, the fluid pathway controlled by a valve to the second chamber, the valve changeable from a locked closed position wherein the valve cannot be opened, and fluid flow is prevented between the first chamber and the second chamber, to an unlocked closed position wherein the valve is openable, and fluid flow is prevented between the first and second chamber; and to an unlocked open position wherein fluid flow can occur between the first chamber and the second chamber, wherein upon a first action, the valve is changeable from the locked closed position to the unlocked closed position, upon a second action comprising a change in pressure in the fluid pathway, the valve is changeable from the unlocked closed position to the unlocked open position, allowing fluid flow between the first and second chambers, wherein the pressure-sensitive sleeve must be in the armed position for the first and second actions to change the valve; and wherein upon reaching a threshold pressure of fluid in the second chamber when the valve is in the unlocked open position, the pressure-sensitive sleeve moves from the armed position to an open position where the pressure-sensitive sleeve is axially misaligned with the at least one port.

[0022] When the pressure-sensitive sleeve is in the sealed position, the valve is prevented from changing from the locked closed position.

[0023] The second action may be a decrease in pressure in the central passage to a lower pressure threshold. The first action may be a change in pressure in the central passage. The first action may be an increase in pressure in the central passage to an upper pressure threshold.

[0024] The remote open valve assembly may further comprise a biasing device, wherein when the valve is in the unlocked closed position, the biasing device is positioned to bias the valve in the unlocked closed position when there is a predetermined fluidpressure in the fluid pathway. The biasing device may be positioned to bias the valve in the unlocked closed position until the lower pressure threshold is reached.

[0025] The remote open valve assembly may further comprise retaining means for retaining the valve in the locked closed position, wherein the retaining means are releasable upon the first action to change the valve to the unlocked closed position. The retaining means may include a spring pin. The retaining means may comprise a j-track configuration.

[0026] The remote open valve assembly may further comprise a fluid pathway in the pressure-sensitive sleeve for connecting the first and second chambers, the valve positioned in the fluid pathway. The remote open valve assembly may further comprise a barrier device in the fluid pathway for preventing fluid flow to the valve until a barrier pressure threshold is reached when the pressure-sensitive sleeve is in the armed position. The barrier device may comprise a burst disc.

[0027] The remote open valve assembly may further comprise a second sleeve longitudinally slidable within the housing for allowing and preventing fluid access through the at least one port when the pressure-sensitive sleeve is in the sealed position.

[0028] According to the disclosure, there is provided a method for remotely opening a remote open valve assembly integrated within a casing string disposed in a subterranean reservoir, the remote open valve assembly comprising a pressure-sensitive sleeve movable within a housing defining a central passage therethrough, the pressure-sensitive sleeve movable between a sealed position, an armed position and an open position, the method comprising the steps: a) when the pressure-sensitive sleeve in the armed position, injecting fluid into the central passage to fill a first chamber in the remote open valve assembly with fluid; b) increasing fluid pressure in the central passage to unlock a valve to a second chamber in the remote open valve assembly; and c) decreasing fluid pressure in the central passage to open the valve and allow the second chamber to fill with fluid, wherein upon reaching a threshold pressure in the second chamber, the pressuresensitive sleeve shifts to the open position.

[0029] The method may further comprise, prior to step a), arming the remote open valve assembly by shifting the pressure-sensitive sleeve from the sealed position to the armed position.

[0030] In step b), the fluid pressure may be increased to balance forces on the valve from opposite directions to unlock the valve. In step b), the fluid pressure may be increased to open a barrier device.

[0031] According to the disclosure, there is provided a well completion system for producing fluids from a subterranean formation via a wellbore provided in the subterranean formation, comprising a casing string extending along the well and comprising at least one remote open valve assembly.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The attached figures illustrate embodiments of the present technology described herein. These embodiments are intended to provide a better understanding of the disclosure and how the disclosure may be put into practice. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the disclosure. Similar reference numbers indicate similar components.

[0033] FIG. 1 shows a cross-sectional drawing of a typical well completion comprising at least one typical valve assembly.

[0034] FIG. 2A shows an isometric view of a typical valve assembly.

[0035] FIG. 2B shows a cutaway isometric view of a typical valve assembly.

[0036] FIG. 3A shows an axial cross-section of a typical valve assembly with two sleeves in the closed configuration.

[0037] FIG. 3B shows an axial cross-section of a typical valve assembly with two sleeves in the open configuration.

[0038] FIG. 4A shows an partial axial cross-section of a remote open valve assembly in the closed configuration and having a pressure-sensitive sleeve and a second sleeve.

[0039] FIG.4B and 4C show axial cross-sections of the remote valve assembly of FIG.4A taken through the sections flanking the third chamber and highlighting the different piston areas formed by the first chamber and second chamber, respectively.

[0040] FIG. 5A shows a partial cross-section through one side of a remote open valve assembly with a spool valve housed within the pressure-sensitive sleeve.

[0041] FIG. 5B shows a top view of a remote open valve assembly in an armed configuration and showing the fluid pathway is fluid filled up to the spool valve land, the spool valve being in a locked position.

[0042] FIG. 5C shows a top view of a remote open valve assembly in a valve open position, showing the fluid pathway and the second chamber are fluid filled, the spool valve land lined up with the inlet and outlet.

[0043] FIG. 6A shows a partial cross-sectional end view of a retaining mechanism comprising a spring pin housed within the sleeve and protruding into the spool valve.

[0044] FIG. 6B shows a partial cross-sectional end view of a retaining mechanism comprising a spring pin housed within the sleeve, the spring pin retracted away from the spool valve.

[0045] FIG. 7A shows a drawing of a spool valve having a j-track on the outer surface.

[0046] FIG. 7B shows a schematic of the j-track, highlighting the positions of the j-pin at various stages for operation of the remote open valve assembly.

[0047] FIGs. 8A to 8D show partial cross-sectional views of remote open valve assemblies, in the closed (8A and 8C) and regulated positions, where a functional region is present on the sleeve (8A and 8B) or disposed within the port(s)(8C and 8D).

[0048] FIG. 9 shows partial cross-sections through the thickness of a side of a remote open valve assembly showing the progression of fluid movement through the sealed, armed, valve unlocked, valve open, and shifted configurations.

[0049] FIG. 10 is a flow chart showing a sequence of events for operating a valve assembly to re-open the valve assembly remotely using a pressure event.

[0050] FIG. 11 is a chart showing pressure versus time in the central passage of the valve assembly during operation.DETAILED DESCRIPTION

[0051] Techniques described herein relate to remote open valve assemblies that can be remotely opened using a pressure event, eliminating the need for a downhole tool to open the valve assemblies.

[0052] Various aspects of the disclosure will now be described with reference to the figures. For the purposes of illustration, components depicted in the figures are not necessarily drawn to scale. Instead, emphasis is placed on highlighting the various contributions of the components to the functionality of various aspects of the disclosure. A number of possible alternative features are introduced during the course of this description. It is to be understood that, according to the knowledge and judgment of persons skilled in the art, such alternative features may be substituted in various combinations to arrive at different embodiments of the present disclosure.

[0053] Referring to FIG. 1, a typical completed well 1 comprises a casing string 2 extending vertically down from the surface 3 (or seabed) through a wellbore 4, drilled into a subterranean formation 8, before leveling off to a relatively horizontal section and ending at the toe 5. For some well completions, isolation material, typically cement, may be passed down the casing string central passageway 6 out the toe 5 and back up through a wellbore annulus 7, between the casing string 2 and wellbore 4, to seal off the wellbore annulus 7. For closed end wells, cementing results in a complete seal at the toe 5. Alternatively, packers may be used for isolation of the wellbore annulus 7 between sections, each section including one or more valve assemblies 10 incorporated as part of the casing string.

[0054] Referring to FIG. 2A and 2B, a typical valve assembly 10 generally includes a tubular housing 12 with a central passage 14 therethrough and one or more ports 16 for allowing fluid communication between the central passage and the subterranean formation adjacent the valve assembly. In some embodiments, the housing 12 may be assembled from multiple components, such as, for example, from an uphole sub, central sub, and downhole sub, coupled together via threaded connections or other mechanism known in the art. In some embodiments, in light of developing 3D printing technology, the housing 12 may be formed as a single piece, eliminating the need for assembly prior to integration within a casing string. Due to inclusion of a sleeve within the housing, the O.D. of the housing may exceed that of casing string between valve assemblies. The uphole and downhole ends of housing 12 may include threading (not shown) or other means forconnection to components for construction of a casing string, including other valve assemblies or tubulars typically used for this purpose. The central passage 14 of valve assembly 10 contributes to and is continuous with a casing string central passageway 6, meaning control of pressure within the central passage 14 can be achieved by manipulating pressure within the casing string central passageway 6.

[0055] While valve assemblies may have multiple sleeve components, the example of a typical sleeve described below is for a two sleeve valve assembly. Referring to FIG. 2B, 3A, and 3B, a first sleeve 20a and second sleeve 20b may be disposed in the housing 12 and are movable with respect to housing 12 to selectively provide or deny access through the ports depending on relative axial positioning of the sleeves 20a and 20b with respect to the ports 16. The range of movement of first sleeve 20a and second sleeve 20b is dictated by hard stops which limit axial movement within the housing 12. In some embodiments, the hard stops may be in the form of an uphole shoulder 12a or a downhole shoulder 12b located on the inner surface of housing 12 that limit further uphole and downhole movement, respectively. For valve assemblies with more than one sleeve, a hard stop may also be provided by the uphole or downhole end of the other sleeve(s) present within the housing. The ports 16 may be closed where one of first sleeve 20a (as shown in FIG. 3A) and second sleeve 20b are axially aligned with ports 16, preventing flow therethrough, or ports 16 may be open (as shown in FIG.2B and 3B), where both the first sleeve 20a and the second sleeve 20b are axially misaligned from ports 16, allowing flow therethrough. By axially aligned, it is meant that a sleeve is in a position along the axial length of the completed well coincident with the ports, including seals on opposite sides that are designed to prevent flow into the annular space between the sleeve and the housing. In essence, axially aligned means at least a length of a sleeve spans across the ports and the seals directly adjacent to and flanking the ports.

[0056] Valve assembles have two general configurations in relation to the ports: Closed (no access through the ports) or open (access through the ports from the central passage). In a closed configuration, a sleeve is axially aligned with the port, preventing flow between the central passage and the surrounding reservoir. In a single sleeve valve assembly, alignment of the single sleeve relative to the port prevents access through the ports, and in multiple sleeve embodiment, alignment of any of the sleeves with the port prevents access through the ports. In an open configuration, no sleeve is axially alignedwith the port(s), allowing flow between the interior of the sleeve and the surrounding reservoir. Valve assemblies may also be capable of more specific configurations, including use of inflow control, flow regulation, and or screening, features of which may be incorporated into one or more sleeves within the valve assembly.

[0057] Seals 80 on the inner surface of the housing, or on the outer surface of a sleeve act to restrict flow or ingress of material into the annular space between the sleeves and housing. Typically, seals 80 comprise an O-ring, and possibly back-up rings, within a groove on the inner surface of the housing or on the outer surface of the sleeve. For simplicity, only two seals 80 are labeled in FIG. 3A / 3b.

[0058] Means for shifting sleeves using a downhole tool are well known, typically by lowering the downhole tool via coiled tubing or wireline into the completed well, locating the tool in a target sleeve, assisted by a locate profile 21, formed relative to the position of the first sleeve 20a and second sleeve 20b relative to the uphole shoulder 12b, gripping the sleeve and isolating pressure (e.g. using packers), and mechanically pulling or hydraulically pushing (coiled tubing conveyed tools only) by increasing pressure within the casing string. Movement of the sleeves by directed manipulation is with an intent to address access through the one or more ports 16.

[0059] Described herein is a remote open valve assembly that comprises a pressuresensitive sleeve that can be shifted away from ports in the housing by operation of opposing pistons within the annulus between the sleeve and the housing, and without the use of a downhole tool. In some embodiments, a pressure-sensitive sleeve having opposing pistons comprising different piston areas can be shifted by fluidly connecting piston chambers and dropping the pressure within the central passage. In some embodiments, the piston with the larger piston area acts to move the sleeve away from ports in the housing to open the remote open valve assembly, allowing fluid access between the central passage and the surrounding formation. In some embodiments, ports in the remote open valve assembly are opened by dropping the central passageway pressure to shift a pressure-sensitive sleeve away from the ports.

[0060] As will described in detail below, the remote open valve assembly described includes three chambers between the annulus of a sleeve and the housing. The middle chamber is sealed and provides a pressure reference for the chambers on opposite sides of the middle chamber. By varying the pressure differential between the opposing sidesrelative to the middle chamber, the sleeve can be manipulated to move towards the side with the smaller pressure differential.

[0061] Shown in FIG. 4A is an axial cross-sectional view of a portion of a remote open valve assembly 100 comprising a pressure-sensitive sleeve as described herein. Features common to known valve assembly configurations, as described above, will be identified with identical reference numbers. As shown, the remote open valve assembly 100 comprises a central passage 14, a housing 12, and a first end 13 and a second end 15. While valve assemblies are typically shown with the uphole end (or first end 13) on the left and the downhole end (or second end 15) on the right, it should be understood that remote open valve assembly 100 may be installed in either orientation. That is, the first end 13 may be the downhole end and the second end 15 may be the uphole end. While a second sleeve 20b is also present in the embodiment shown, in some embodiments the pressuresensitive sleeve 20 is the only sleeve present. This is particularly relevant for using the remote open valve assembly described herein as a toe sleeve, which will be described in detail below.

[0062] The remote open valve assembly 100 comprises a first chamber 30, a second chamber 32, and a third chamber 34, all chambers disposed in the annular space between the housing 12 and pressure-sensitive sleeve 20. As can be seen in the figure, each of the chambers are formed by the interior surface of the housing in combination with the external surface of the sleeve. Each chamber extends circumferentially around the sleeve, forming, in essence, a space in a shape similar to the sleeve it surrounds, first chamber 30 and second chamber 32 function as dual pistons that act to move the pressuresensitive sleeve 20 when both chambers become fluid filled. The first chamber 30 and second chambers 30 are connected by a fluid pathway 50, access through the fluid pathway 50 controlled by a valve 52 that can be locked, then unlocked before opening in response to a drop in pressure.

[0063] The second chamber 32 having a larger piston area (AP2 - shaded area in FIG.4C) than the piston area (API - shaded area in FIG. 4B) of the first chamber 30 allows for the creation of competing pressure differentials between the first and second chambers, relative to sealed chamber 40, to create a piston action for shifting the pressure-sensitive sleeve 20 away from ports 16 to allow fluid communication between the central passage 14 and the surrounding formation 8. The third chamber 34, located between the first andsecond chambers along a longitudinal axis 22 of the remote open valve assembly, is gas filled, at low pressure, preferably ambient air pressure when the third chamber is sealed during formation of the remote open valve assembly. The gas within third chamber 34 may be a mixture of different gases (e.g. air), or relatively pure gas (e.g N2, CO2).

[0064] An essential aspect of the fluid pathway 50 is that the connection it provides between the first and second chamber can be controlled, preferably by means of a valve that can be locked, unlocked, and then opened. In that sense, the shape and size of the fluid pathway are not critical, beyond satisfying structural integrity, spatial constraints, and compatibility with regulation via the valve mechanism. For example, in some embodiments, the fluid pathway 50 is disposed within the thickness of the pressuresensitive sleeve 20. In some embodiments, the fluid pathway 50 is tube shaped, having a circular cross-sectional area with a diameter less than the thickness of the sleeve. The cross-sectional shape for fluid pathway 50 may also include oval, square, rectangular, or irregular shape, and may vary along the length of the fluid pathway 50. In some embodiments, the fluid pathway 50 comprises multiple paths, converging to a single exit point within the second chamber 32.

[0065] In some embodiments, the fluid pathway 50, as illustrated in FIG. 4A, originates from a location within first chamber 30. In some embodiments, the fluid pathway 50 originates at a location other than from within first chamber 30. For example, fluid pathway 50 may originate at a location within the central passage 14, extending radially through the thickness of pressure-sensitive sleeve 20. In some embodiments, fluid pathway 50 may originate on the inner surface of housing 12 and extend, axially and or radially, through the thickness of the housing 12.

[0066] An optional burst disk 54 along fluid pathway 50 may be included to provide control in timing for unlocking valve 52. The remote open valve assembly 100 includes multiple seals (not labeled for clarity) for limiting flow in annular spaces, where selecting positioning and configuration, which may vary, falls within the purview of the skilled person.

[0067] The valve controlling access between the first and second chamber resists opening until pressure in the central passage above a threshold, then unlocked before opening to provide the fluid connection between the two chambers. The valve has three configurations: locked closed, unlocked closed, and open. In some embodiments, the valve is a spool valve (FIG. 5A) in combination with locking means. A spool valve 52inserted within fluid pathway 50, with seals 52a position on the spool valve lands 53a and 53b prevent flow around the spool valve lands, only allowing flow in the spool valve gap 53c when the spool valve lands are misaligned with the spool valve inlet 56 and the spool valve out 55. Locking means are releasable, and, once unlocked, the position of the valve is determined by opposing forces on each side of the spool valve: the pressure in the first chamber versus the force applied via a biasing means which pushes the spool towards the first chamber.

[0068] In some embodiments, in the locked closed position, shown in FIG. 5B, the spool valve land 53 of valve 52 is prevented from moving to a position that allows flow through the valve, maintaining fluid isolation between first chamber 30 and second chamber 32. In some embodiments, a retaining means 58 maintains valve 52 in the locked closed position. The retaining means 58 are releasable to change the valve to the unlocked closed position, where the spool valve land 53 can move under certain circumstances, and fluid can pass through the valve and flood chamber 30 (dark gray shading in FIG. 5B and 5C).

[0069] The retaining means may be in the form of a spring pin 60, an example of which is shown in FIGS. 6A and 6B. The spring pin may be secured within a pin housing 60d the sleeve, with a pin 60a that extends into a borehole 52b (or circumferential groove) on the surface of the spool valve 52, retaining the valve 52 in the locked closed position, shown in FIG. 6A. In another embodiment, the retaining means comprise a j-track configuration, where in the locked closed position, a j-pin, secured to the sleeve, is positioned within a j-track 66 on the outer surface of spool valve 52, where moving the spool valve land 53 into an open position is prevented by the track (FIG. 7A).

[0070] The remote open valve assembly 100 may include a biasing device 70 positioned to bias the valve 52 in the locked closed position under certain pressure conditions in the central passageway and fluid pathway. The biasing device 70 may be a spring stack that biases the valve 52 in one direction (for example, the uphole direction). The biasing device may comprise other suitable means besides a spring stack. For example, a gas-filled pressure chamber could be used to bias the retaining device in the locked closed position. When the biasing device is used with a retaining means like a spring pin, the force from the biasing device causes friction between the pin end 60c and valve 52 to keep them engaged. When certain pressure conditions exist, for exampleneutral forces in an uphole and downhole direction on the valve 52, there is no longer friction between the pin end 60c and valve 52, and the spring 60b in the retaining device causes the pin 60a to move in a direction shown by arrow 62 to release the pin end 60c from engagement with the valve 52, as shown in FIG. 6B. This changes the valve to the unlocked closed position, where the spool valve land 53 can move to where fluid can pass from the inlet 54 through to the outlet 57 (FIG. 5C).

[0071] When the biasing device is used with retaining means comprising a j-track configuration, the force from the biasing device keeps the j-pin in the shorter leg (indicated by 1 & 2 in FIG. 7B) of the j-track. When pressure conditions change, and the force from the biasing device is insufficient to keep the j-pin in the short leg of the j-track, the spool valve shifts and rotates so that the j-pin moves to 3 in FIG. 7B. This can happen with an increase in pressure in the central passage. The spool valve 52 would now be in the unlocked closed position, where the spool valve land 53 can move, in response to a decrease in pressure in the central passage (4&5 in FIG. 7B), to where fluid can pass from the inlet 54 through to the outlet 57. Any increase in pressure will keep the valve open as the pin would only move a short distance (* in FIG. 7B).

[0072] As shown in FIG. 7A the j-track 66 is formed on the surface of the valve 52, and the j-pin is affixed to the sleeve. It would be apparent to the skilled person that the j-track can be a part of the sleeve, and the j-pin can radially extend from the valve 52.

[0073] Other possibilities for restraining means include a hydraulic latch, a dissolvable retaining device, and a shear pin. The retaining means may include a feature to prevent the valve 52 from returning to the unlocked closed position and the locked closed position after it has been changed to the open position.

[0074] Providing direct access through ports is not always desirable. For example, for sand-laden formations it may be preferable to apply a screen across the ports to prevent larger particulate matter from passing through the ports and into the central passage. For some wells, like injection only wells, it may be preferable to include flow regulation to provide more even injection distribution across multiple zones. In some embodiments, ports in the remote open valve assembly are regulated by dropping the central passageway pressure to shift the sleeve away from the ports. In some embodiments, the ports are regulated by restricting access for particulate matter using a screen. In someembodiments, the ports are regulated by using an inflow control device for restricting flow rate into the formation, or for reducing water or gas inflow into the central passage.

[0075] Providing functionality in the form of regulation of flow, either with a screen, inflow control device, or other means of regulation, can involve including a functional region 80 as part of the sleeve (FIG. 8A and 8B), or as a modification to the ports (FIG.8C & 8D). As the sleeve is shifted towards the first end 13 the functional region is within the flow path between the central passage 14 and the surrounding formation 8. Functional regions regulate the flow through the ports beyond allowing unrestricted access. Functional regions may provide screening, inflow control, one way flow via a check valve, or even a barrier device (e.g. burst disk) that can be ruptured when desirable.

[0076] Methods for operating the remote open valve assembly 100 will now be described with reference to FIGS. 9, 10, and 11. FIG. 9 illustrates the configurations for remote open valve assembly 100 depending on the position of the pressure-sensitive sleeve 20 relative to ports 16, and the fluid status for the first and second chambers (e.g. fluid filled as noted by gray shading). The configurations of remote open valve assembly 100 include a sealed position, an armed position, an unlocked position, an open position, and a shifted position

[0077] First, to prepare the remote open valve assembly for remote re-opening, the pressure-sensitive sleeve 20 is shifted from the sealed position to the armed position. This may be done using a shifting tool or other suitable mechanical device, and it may be done well in advance of the remote re-opening of the remote open valve assembly. For example, when fracturing operations are complete, the pressure-sensitive sleeve may be moved to the armed position prior to removing the shifting tool from the well. Alternatively, the remote open valve assembly may be run into a wellbore already in the armed position, after which the first sleeve can be remotely shifted without requiring a tool to move the sleeve from sealed position to the armed position. The pressure-sensitive sleeve can be kept in the armed position for a long period of time until the further operations, e.g. production, are ready to commence. When the pressure-sensitive sleeve 20 is in the sealed position, prior to point 1 in FIG. 11 (gray shaded region), changes in pressure in the central passage 14 do not affect the pressure-sensitive sleeve 20, and by extension chambers 20 and 30. That is, chambers 20 and 30 are isolated from pressure events in the central passage 14 when the pressure-sensitive sleeve 20 is in the sealed position.

[0078] In the armed configuration, the pressure-sensitive sleeve 20 is axially aligned with ports 16, preventing flow of fluid from the central passage 14 to the formation 8, or vice versa, through the ports 16. Loss of sealing engagement with the housing 12 via seals in close proximity to the first end 13 allows first chamber 30 to become fluid filled. The armed configuration allows for a series of events to occur to move the pressure-sensitive sleeve to the open position, where the pressure-sensitive sleeve 20 is axially misaligned from port 16 and doesn’t contribute to the prevention of flow of fluid from the central passage 14 to the formation 8, or vice versa, through ports 16. As described below, the intermediate statuses of the remote open valve assembly do not relate directly to the allowance or prevention of the flow of fluid through port 16, but rather to the control of fluid flow within and between opposing chambers, an interaction which permits remote control, using pressure events, of the pressure-sensitive sleeve 20 and its axial position relative to port 16.

[0079] With the pressure-sensitive sleeve in the armed position and the first chamber 30 in fluid connection with the central passage 14, fluid present in the central passage may fill the first chamber with fluid (denoted by gray shading in FIG. 9 and step 2 in FIG.10). In some embodiments, the barrier device 54, if present, is removed (e.g. bursting a burst disc) by increasing pressure above a barrier threshold pressure, allowing fluid into the fluid pathway 50 up to valve 52, as shown in the Armed - barrier device defeated configuration of FIG. 9. Next, fluid pressure is increased in the central passage 14 to an upper pressure threshold shown as 3 in FIGS. 10 and 11, which causes the valve 52 to the second chamber 32 to move from the locked closed position shown as step 3 in FIGS.10 and 11, to the unlocked closed position shown in FIG. 9 (valve 52 has moved to the right and can rotate to the open position). This is followed by the release of the retaining means 60. In some embodiments, the retaining means (e.g. a spring pin) are released by balancing forces on the valve 52 from both the uphole and downhole direction. The forces acting on the valve include a hydraulic force in one direction, caused by the fluid pressure, and a force in the opposite direction generated by the biasing device. When these forces are balanced, the retaining device comprising a spring pin releases. For j-track configurations, the force on the valve acts to move the j-track towards the biasing device, causing the valve to rotate and move the j-pin out of the short leg of the track. Any subsequent movement in the opposite direction will push the j-pin into the longer leg,allowing the valve to travel far enough so that the spool valve can open. Alternatively, other types of retaining means and means for releasing them can be used.

[0080] Next, the pressure is decreased in the central passage 14 until a lower pressure threshold is reached, shown as step 4 in FIGS. 10 and 11, causing the valve 52 to change from the unlocked closed position shown in FIG. 9 to the unlocked open position shown. This may occur when the forces acting on one side of the valve, i.e. the hydraulic pressure in the central passage and flow pathway, is lower than the forces acting on the opposite side of the valve, i.e. the force generated by the biasing device 70.

[0081] After the valve has changed to the unlocked open position, fluid flows into the second chamber 32 to fill it with fluid, shown as step 5 in FIGS. 10 and 11. Upon dropping to a threshold pressure in the second chamber, a piston action is created to cause the pressure-sensitive sleeve 20 to move from the armed position to the open position. This opens the port 16, allowing fluid flow between the central passage and the formation, which typically causes a large pressure drop in the central passage shown by point 5 in FIG. 11.

[0082] The changes in pressure in the central passage 14 are measurable during operation of the remote open valve assembly and provide information to help determine what is occurring in the remote open valve assembly. For example, a sudden drop in pressure at point 5 allows an operator to know that the pressure-sensitive sleeve has likely shifted to the open position. Other data can also be used to determine the operation stage of the remote open valve assembly. For example, sensing devices such as an acoustic sensor could be used to hear when the pressure-sensitive sleeve shifts in the remote open valve assembly. In another example, when multiple remote open valve assemblies are used in a casing string, tracer can be installed in the ports of each remote open valve assembly such that once production starts, it can be determined which ports are open.

[0083] In some embodiments, there is no barrier device 54, and the increase in pressure causes the release of the retaining means without having to open a barrier device such as a burst disc.

[0084] In some embodiments, the retaining means are released through other means than by a balance of pressure on the valve 52.

[0085] In some embodiments, the ports 16 are the same ports used for well completion operations. In some embodiments, the ports 16 are different ports than the ones used for well completion operations.

[0086] Any description and illustration showing downhole and uphole directions may be reversed.

[0087] The remote open valve assembly may be integrated within a casing string, wherein the remote open valve assembly 100 is connected to a valve assembly without a pressure-sensitive sleeve, or typical valve assembly. The remote open valve assembly may be positioned either uphole or downhole of a typical valve assembly. In some embodiments, a well completion system comprises at least one remote open valve assembly. In other embodiment, the well completion system further comprises at least one typical valve assembly.

[0088] The remote open valve assembly may work as a toe sleeve. In this embodiment, a remote open valve assembly, or remote open toe valve assembly, with one sleeve, the pressure-sensitive sleeve, is installed as the final valve assembly in the toe region of the completed well. In this embodiment, the remote open toe valve assembly is installed, preferably, in the armed configuration. When pre-production processes (e.g. pressure testing, fracturing) are completed, the burst disc may be defeated, and the pressure protocol can be used to create access to the formation at the toe end of the well.

[0089] Multiple remote open valve assemblies 100 may be integrated within the casing string. When an action takes place to operate the remote open valve assembly, it may work to operate all the remote open valve assemblies. For example, a pressure event that causes the pressure-sensitive sleeve to open in one remote open valve assembly may cause the pressure-sensitive sleeves in all the remote open valve assemblies to open. This may happen concurrently. Indeed, it is preferable that all remote open valve assemblies open within the same time frame. Remote opening of a single remote open valve assembly, while leaving other remote open valve assemblies in the armed (or sealed) position, reduces pressure integrity of the well, negatively impacting control of pressure within the central passage. Without adequate pressure control, the remaining remote open valve assemblies may be unresponsive to pressure protocols used for shifting sleeves in remote open valve assemblies.

[0090] A completed well with multiple remote open valve assemblies should be designed with consideration as to positions within the casing string where the remote open valve assemblies are situated. Remote open valve assemblies in a vertical section will be subjected to lower hydrostatic pressure than those present in a horizontal section that is typically at a lower depth. That is, the shifting of pressure-sensitive sleeves in different remote open valve assemblies within the casing string may not be simultaneous due to different pressure thresholds being needed for each remote open valve assemblies.

[0091] In designing a casing string, pressure thresholds for shifting pressure-sensitive sleeves may be customized according to position within the casing string. Customization can include varying the force imparted by the biasing means and or selecting piston areas that work to shift the sleeves. Calculation of pressure thresholds in light of position along the casing string, and in consideration of the hydraulic pressure and biasing means, falls within the purview of the person skilled in the art.

Claims

1. CLAIMS1. A remote open valve assembly for integration within a wellbore string disposed within a subterranean formation, comprising:a housing comprising a tubular wall defining a central passage therethrough and at least one port extending through the tubular wall; anda pressure-sensitive sleeve longitudinally slidable within the housing between a position where the pressure-sensitive sleeve is axially aligned with the at least one port and a position where the pressure-sensitive sleeve is axially misaligned with the at least one port;wherein the pressure-sensitive sleeve may be shifted from the axially aligned position to the axially misaligned position by operation of opposing pistons within an annulus between the pressure-sensitive sleeve and the housing, and without the use of a downhole tool.

2. The remote open valve assembly of claim 1 wherein the pressure-sensitive sleeve may be shifted to the axially misaligned position by dropping the pressure within the central passage.

3. The remote open valve assembly of claim 1 or 2, further comprising:a first chamber disposed between the housing and the pressure-sensitive sleeve and having a first piston area;a second chamber disposed between the housing and the pressure-sensitive sleeve and positioned between the first chamber and the at least one port along a longitudinal axis of the remote open valve assembly, and having a second piston area, the second piston area greater than the first piston area;a third chamber disposed between the housing and the pressure-sensitive sleeve, and positioned between the first and second chambers along a longitudinal axis of the remote open valve assembly; anda fluid pathway connecting the first chamber to the second chamber, the fluid pathway controlled by a valve to the second chamber, the valve changeable from:a locked closed position wherein the valve cannot be opened, and fluid flow is prevented between the first chamber and the second chamber;to an unlocked closed position wherein the valve is closed but openable, and fluid flow is prevented between the first and second chamber; andto an unlocked open position wherein fluid flow can occur between the first chamber and the second chamber.

4. The remote open valve assembly of claim 3, wherein the valve may be kept in a locked position by retaining means.

5. The remote open valve assembly of claim 4, wherein the valve is a spool valve.

6. The remote open valve assembly of claim 5, wherein the retaining means are selected from the group comprising:a spring pin mechanism: anda j-track configuration.

7. The remote open valve assembly of claim 5, further comprising a biasing means for driving the spool valve to the unlocked open position.

8. The remote open valve assembly of claim 7, wherein the biasing means comprises a spring stack disposed around the pressure-sensitive sleeve and within the second chamber.

9. The remote open valve assembly of claim 7, wherein the spool valve can be converted to the unlocked closed position by defeating the retaining means in response to increasing the pressure in the first chamber to where the force applied to the spool valve by the pressure in the first chamber exceeds the force applied to the spool valve by the biasing means.

10. The remote open valve assembly of claim 9, wherein the spool valve can be converted to the unlocked open position by decreasing the pressure in the first chamberto where the force applied to the spool valve by the biasing means exceeds the force applied by pressure in the first chamber.

11. The remote open valve assembly of claim 10, wherein converting the spool valve to the unlocked open position allows fluid to pass through the spool valve, allowing fluid communication, via the fluid pathway, between the first and second chambers, filling the second chamber.

12. The remote open valve assembly of claim 11, wherein filling the second chamber results in shifting, due to the second piston area being greater than the first piston area, of the pressure-sensitive sleeve away from the at least one port, allowing fluid within the central passage to move through the at least one port and into the subterranean formation.

13. The remote open valve assembly of the any of the preceding claims, wherein the pressure-sensitive sleeve progresses through the configurations of:an armed configuration, wherein the pressure-sensitive sleeve is axially aligned with the at least one port and the first chamber is filled with fluid;an unlocked closed configuration, wherein the pressure-sensitive sleeve is axially aligned with the at least one port, the first chamber and the fluid pathway are filled with fluid, and the valve is in the unlocked closed position; anda shifted configuration, wherein the pressure-sensitive sleeve is axially misaligned with the at least one port, and the first chamber, fluid pathway, and second chamber are fluid filled.

14. The remote open valve assembly of claim 14, further comprising the pressuresensitive sleeve in a sealed configuration prior to the armed configuration, where the pressure-sensitive sleeve is misaligned from the at least one port and the first chamber is not fluid filled.

15. The remote open valve assembly of claim 13 or 14, further comprising a barrier device within the fluid pathway disposed between the first chamber and the valve.

16. The remote open valve assembly of claim 15, wherein the barrier device is defeated by increasing pressure above a burst threshold before the pressure-sensitive sleeve progresses from the armed configuration to the unlocked closed position.

17. The remote open valve assembly of any of the preceding claims, wherein a functional region is disposed within the at least one port.

18. The remote open valve assembly of any of the preceding claims, wherein the pressure-sensitive sleeve comprises an extension comprising a functional region, and shifting the pressure-sensitive sleeve to the axially misaligned position comprises shifting the functional region into an axially aligned position relative to the at least one port.

19. The remote open valve assembly of claim 17 or 18, wherein the functional region is selected from one or more of the list comprising:a screen;a check valve;an inflow control device; anda barrier device.

20. A remote open valve assembly for integration within a casing string disposed in a subterranean formation, comprising:a housing comprising a tubular wall defining a central passage therethrough and at least one port extending through the tubular wall;a pressure-sensitive sleeve longitudinally slidable within the housing between a position where the pressure-sensitive sleeve is axially aligned with the at least one port and a position where the pressure-sensitive sleeve is axially misaligned with the at least one port;a first chamber disposed between the housing and the pressure-sensitive sleeve and having a first piston area, wherein when the pressure-sensitive sleeve is in a sealed position, fluid flow is prevented between the central passage and the firstchamber, and when the pressure-sensitive sleeve is in an armed position, the first chamber is in fluid connection with the central passage;a second chamber disposed between the housing and the pressure-sensitive sleeve and positioned between the first chamber and the at least one port along a longitudinal axis of the remote open valve assembly, and having a second piston area, the second piston area greater than the first piston area;a third chamber disposed between the housing and the pressure-sensitive sleeve, and positioned between the first and second chambers along a longitudinal axis of the remote open valve assembly;a fluid pathway connecting the first chamber to the second chamber, the fluid pathway controlled by a valve to the second chamber, the valve changeable from:a locked closed position wherein the valve cannot be opened, and fluid flow is prevented between the first chamber and the second chamber;to an unlocked closed position wherein the valve is openable, and fluid flow is prevented between the first and second chamber; andto an unlocked open position wherein fluid flow can occur between the first chamber and the second chamber.wherein upon a first action, the valve is changeable from the locked closed position to the unlocked closed position;wherein upon a second action comprising a change in pressure in the fluid pathway, the valve is changeable from the unlocked closed position to the unlocked open position, allowing fluid flow between the first and second chambers;wherein the pressure-sensitive sleeve must be in the armed position for the first and second actions to change the valve; andwherein upon reaching a threshold pressure of fluid in the second chamber when the valve is in the unlocked open position, the pressure-sensitive sleeve moves from the armedposition to an open position where the pressure-sensitive sleeve is axially misaligned with the at least one port.

21. The remote open valve assembly of claim 20, wherein when the pressure-sensitive sleeve is in the sealed position, the valve is prevented from changing from the locked closed position.

22. The remote open valve assembly of claim 20 or 21, wherein the second action is a decrease in pressure in the central passage to a lower pressure threshold.

23. The remote open valve assembly of any one of claims 20-22, wherein the first action is a change in pressure in the central passage.

24. The remote open valve assembly of claim 23, wherein the first action is an increase in pressure in the central passage to an upper pressure threshold.

25. The remote open valve assembly of any one of claims 20-24, further comprising a biasing device, wherein when the valve is in the unlocked closed position, the biasing device is positioned to bias the valve in the unlocked closed position when there is a predetermined fluid pressure in the fluid pathway.

26. The remote open valve assembly of claim 22, further comprising a biasing device, wherein when the valve is in the unlocked closed position, the biasing device is positioned to bias the valve in the unlocked closed position until the lower pressure threshold is reached.

27. The remote open valve assembly of any one of claims 20-26, further comprising a retaining device for retaining the valve in the locked closed position, wherein the retaining device is releasable upon the first action to change the valve to the unlocked closed position.

28. The remote open valve assembly of claim 27, wherein the retaining device is a spring pin.

29. The remote open valve assembly of any one of claims 20-28, further comprising a fluid pathway in the pressure-sensitive sleeve for connecting the first and second chambers, the valve positioned in the fluid pathway.

30. The remote open valve assembly of claim 29, further comprising a barrier device in the fluid pathway for preventing fluid flow to the valve until a barrier pressure threshold is reached when the pressure-sensitive sleeve is in the armed position.

31. The remote open valve assembly of claim 30, wherein the barrier device is a burst disc.

32. The remote open valve assembly of any one of claims 20-31 , further comprising a second sleeve longitudinally slidable within the housing for allowing and preventing fluid access through the at least one port when the pressure-sensitive sleeve is in the sealed position.

33. A method for remotely opening a remote open valve assembly integrated within a casing string disposed in a subterranean reservoir, the remote open valve assembly comprising a pressure-sensitive sleeve movable within a housing defining a central passage therethrough, the pressure-sensitive sleeve movable between a sealed position, an armed position and an open position, the method comprising the steps:a) with the pressure-sensitive sleeve in the armed position, injecting fluid into the central passage to fill a first chamber in the remote open valve assembly with fluid;b) increasing fluid pressure in the central passage to unlock a valve to a second chamber in the remote open valve assembly; andc) decreasing fluid pressure in the central passage to open the valve and allow the second chamber to fill with fluid, wherein upon reaching a threshold pressure in the second chamber, the pressure-sensitive sleeve shifts to the open position.

34. The method of claim 33, further comprising prior to step a), arming the remote open valve assembly by shifting the pressure-sensitive sleeve from the sealed position to the armed position.

35. The method of claim 33 or 34, wherein in step b), the fluid pressure is increased to balance forces on the valve from opposite directions to unlock the valve.

36. The method of any one of claims 33-35, wherein in step b), the fluid pressure is increased to open a barrier device.

37. A well completion system for producing fluids from a subterranean formation via a wellbore provided in the subterranean formation, comprising a casing string extending along the well and comprising at least one remote open valve assembly according to claim 1.

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