CA3036420A1 - Shiftable tubular valve assembly and process for directing fluid flow in a wellbore - Google Patents

Abstract

Various embodiments of a tubular valve assembly for use in conjunction with wellbores and processes of using the valve assemblies are provided. In various example embodiments, the valve assembly comprises one or more side ports covered by a degradable barrier. In a process for controlling fluid flow in a wellbore string, the tubular valve is initially shifted from a port-closed position to a port-open position using high hydraulic pressure, thereby exposing the degradable barrier which begins to disintegrate. Following disintegration of the degradable barrier, fluid communication between the interior and the exterior of the tubular valve assembly is established and fluid can flow from the valve assembly to the well, at low hydraulic pressure.

Description

TITLE: SHIFTABLE TUBULAR VALVE ASSEMBLY AND PROCESS FOR
DIRECTING FLUID FLOW IN A WELLBORE
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates to wells and in particular valve assemblies and processes for directing fluid flow in wells.
BACKGROUND OF THE DISCLOSURE

[0002] The following paragraphs are provided by way of background to the present disclosure. They are not, however, an admission that anything discussed therein is prior art or part of the knowledge of persons skilled in the art.

[0003] Subterranean oil and gas wells require the inflow of hydrocarbon products from reservoir rock formations into the well. Various techniques, commonly known as completions, have evolved to condition a well in order to enable transport of hydrocarbon products from the surrounding rock formation to the wellbore. This includes a technique, known as multistage completion, involving the isolation of multiple zones of a reservoir formation along a wellbore and sequential staged treatment of each zone with stimulation fluids to promote fracturing of the rock formation and flow of hydrocarbons. In order to accomplish this, operators typically install a tubular wellbore string, also known as a completion string or liner.

[0004] For example, in multistage completions known as open hole completions, the completion string commonly contains multiple shiftable sleeve valves flanked by packers, as well as a wellbore isolation valve at the distal end of the string.
Shifting of a sleeve valve results in the opening of a side port in the sleeve housing, allowing fluid communication between the central string bore and the wellbore and rock formation. One well known technique to achieve this involves deploying a ball into the completion string. The ball travels through the completion string until it makes contact with a matching ball seat within a sleeve valve of the completion string. The sleeve valve is designed so that upon the ball making contact with the ball seat, it actuates shifting of the sleeve valve via hydraulic pressure provided from the surface to thereby open the side port in the sleeve housing. At the same time, when the ball contacts the ball seat, the ball can seal off the central string bore. Thus, fluid flow through the string is directed through the side ports, thereby making it is possible to sequentially treat zones from a distal end to a proximal end of the well. The sleeve valve systems used in these operations are generally built to operate under high hydraulic pressures (e.g., in excess of 2,000 psi) and to treat the rock formation at such high pressures to cause fracturing of the rock formation.

[0005] In certain circumstances, it is desirable to install a valve system that allows for fluid treatment of a hydrocarbon bearing rock formation using low hydraulic pressures. For example, following initial treatment, for example, by an initial high pressure hydraulic fracturing operation, it may be desirable to extract further residual hydrocarbon from a rock formation. In such operations, known in the art as "enhanced recovery" operations, it can be desirable to fluid treat a rock formation using low fluid pressures.
SUMMARY OF THE DISCLOSURE

[0006] The following paragraphs are intended to introduce the reader to the more detailed description that follows and not to define or limit the claimed subject matter of the present disclosure.

[0007] In one aspect, the present disclosure relates to wellbore systems.

[0008] In another aspect, the present disclosure relates to tool assemblies for directing fluid flow for use in wellbore systems.

[0009] Accordingly, the present disclosure provides, in one broad aspect, in accordance with the teachings herein, in at least one example embodiment, a tubular valve assembly for directing and controlling fluid flow in a wellbore, the valve assembly comprising:

a first tubular member having a port through a wall of the first tubular member, the port being covered by a fluid degradable barrier; and a second tubular member located exteriorly to the first tubular member and displaceable relative to the first tubular member from a port-closed position to a port-open position;
the second tubular member further being arranged so that in a port-closed position there is no fluid communication from an exterior of the valve assembly to an inner passage of the first tubular member through the port, and the second tubular member covers the degradable barrier to prevent fluid contact between the exterior of the valve assembly and the degradable barrier; and the second tubular member being displaceable by application of a fluid flow in the inner passage of the first tubular member at a hydraulic pressure that is sufficient to cause the second tubular valve to shift from the port-closed position to the port-open position, the degradable barrier in the port-open position being exposed to and contacted by fluid to the exterior of the valve assembly causing the degradable barrier to gradually degrade the barrier for a delay period during which the applied fluid flow in the inner passage can be controlled without regard to an exterior fluid flow that is to the exterior of the tubular valve assembly, and upon disintegration of the degradable barrier a fluid communication is established between the exterior of the valve assembly and the inner passage.

[0010] In at least one embodiment, the valve assembly can include a hydraulic actuation member.

[0011] In at least one embodiment, the hydraulic actuation member can include an actuation aperture forming a second fluid communication between the interior of the valve assembly and the second tubular member.

[0012] In at least one embodiment, the valve assembly further can include a plug or a surface coating that is disposed between the degradable barrier and the inner passage of the first tubular member to protect the degradable barrier from degradation due to fluids in the inner passage of the first tubular member.

[0013] In at least one embodiment, the plug can be a cylindrical plug radially disposed between the inner passage of the first tubular member and the degradable barrier, and upon disintegration of the degradable barrier the plug member is radially exteriorly displaceable by the fluid flow through the inner passage of the first tubular member.

[0014] In at least one embodiment, the port can be an inwardly radially narrowing port.

[0015] In at least one embodiment, the valve assembly can include a shear pin that is arranged to couple the first tubular member to the second tubular member and during the application of the fluid flow in the inner passage of the first tubular member the shear pin is arranged to shear thereby allowing displacement of the second tubular member.

[0016] In at least one embodiment, the delay period can be sufficiently long to hydraulically shift at least one other hydraulically controllable component installed on a tubular string together with the valve assembly from a first operable position to a second operable position.

[0017] In at least one embodiment, the delay period can be from about 48 hours to about 1 hour.

[0018] In at least one embodiment, fluid communication between the exterior of the valve assembly and the inner passage can be established by a second fluid flow at a hydraulic pressure that is sufficient to form a fluid-front in a hydrocarbon bearing rock formation surrounding the valve assembly installed in the wellbore.

[0019] In at least one embodiment, the hydraulic pressure can be from about 100 psi to about 1,000 psi.

[0020] In at least one embodiment, the hydraulic pressure that is sufficient to displace the second tubular member can be larger than the hydraulic pressure that is sufficient to form a fluid-front in a hydrocarbon bearing rock formation.

[0021] In another aspect, the present disclosure relates to processes for controlling fluid flow in a subterranean well. Accordingly, the present disclosure further provides, in one broad aspect, in at least one example embodiment, a process for controlling fluid flow in a wellbore string, the process comprising:
installing a wellbore string in a wellbore, the wellbore string having a central bore therethrough and comprising a side-ported two member tubular valve assembly interconnecting two successive portions of the string, the tubular valve assembly being shiftable from a port-closed position to a port-open position, and having a fluid degradable barrier covering the port, the degradable barrier being covered by one of the tubular valve members in the port-closed position to prevent fluid contact between an exterior of the tubular valve and the degradable barrier; and applying fluid flows to the central bore at sufficient hydraulic pressures to:
cause the tubular valve assembly to shift from the port-closed position to the port-open position;
expose the degradable barrier to the exterior of the tubular valve assembly to permit fluid contact between the barrier and fluid to the exterior of the tubular valve assembly;
degrade the barrier during a delay period until the degradable barrier is disintegrated; and establish fluid communication between the central bore and the exterior of the tubular valve assembly when the barrier is disintegrated.

[0022] In at least one embodiment, the process can further include applying a first fluid flow at a first hydraulic pressure sufficient to cause the tubular valve assembly to shift from the port-closed position to the port-open position, and then applying a second fluid flow at a second hydraulic pressure to establish fluid communication between the central bore and the exterior of the tubular valve assembly.

[0023] In at least one embodiment, the second fluid flow at the second hydraulic pressure can further be sufficient to form a fluid-front in a hydrocarbon-bearing rock formation surrounding the valve assembly to displace hydrocarbons from the rock formation into the wellbore.

[0024] In at least one embodiment, the first hydraulic pressure can be higher than the second hydraulic pressure.

[0025] In at least one embodiment, the first hydraulic pressure can be a pressure of from about 1,000 psi to about 4,000 psi and the second hydraulic pressure can be a pressure of from about 100 psi to about 1,000 psi.

[0026] In at least one embodiment, the process can further include, during the delay period, hydraulically shifting at least one other hydraulically controllable component installed on the tubular string together with the valve assembly from a first operable position to a second operable position.

[0027] In at least one embodiment, the wellbore string can comprise two or more of the side-ported valve assemblies separated from one another by a portion of the wellbore string, and the process further includes applying fluid flow at a sufficient pressure to the central bore to cause each of the two or more side-ported valve assemblies to simultaneously or sequentially shift from the port-closed position to the port-open position.

[0028] In at least one embodiment, the process further includes applying fluid flow at a sufficient pressure to the central bore to cause each of the two or more side-ported valve assemblies to:
(i) shift from the port-closed to the port-open position;
(ii) expose the degradable barrier in each of the valve assemblies to the exterior of the valve assemblies to permit fluid contact between the barriers and fluid to the exterior of the valve assemblies;
(iii) degrade the barrier during a delay period until the degradable barrier is disintegrated; and (iv) establish fluid communication between the central bore and the exterior of the tubular valve assemblies when the barriers are disintegrated; and wherein the performance of all of steps (i) to (iv) is completed for a first of the two side-ported valves before the performance of these steps is initiated in respect of a second of the two or more side-ported valves.

[0029] In at least one embodiment, the wellbore string can be installed inside another larger diameter wellbore string.

[0030] In at least one embodiment, the larger diameter wellbore string can include an additional side-ported valve, and the process further includes upon establishing fluid communication between the central bore and an exterior of the tubular valve assembly, establishing fluid communication between the tubular valve assembly and the wellbore by actuating the side ports of the additional side-ported valve.

[0031] In at least one embodiment, the larger diameter wellbore string can include two or more other side-ported valves, and the process further includes upon establishing fluid communication between the central bore and an exterior of the tubular valve assembly, establishing fluid communication between the tubular valve assembly and the wellbore by actuating the side ports of the two or more other side-ported valves.

[0032] In another aspect, the present disclosure relates to use of the valve assembly of the present disclosure. Accordingly, the present disclosure further provides, in one broad aspect, in at least one example embodiment, a use of a tubular valve assembly to establish a contiguous fluid front in a hydrocarbon bearing rock formation to thereby displace the hydrocarbon from the rock formation into a wellbore, the assembly comprising:
a first tubular member having a port through a wall of the tubular member, the port covered by a fluid degradable barrier;

a second tubular member located exteriorly to the first tubular member and being displaceable relative to the first tubular member from a port-closed position to a port-open position;
the second tubular member further being arranged so that in the port-closed position there is no fluid communication from an exterior of the valve assembly to an inner passage of the first tubular member through the port, and the second tubular member covers the degradable barrier to prevent fluid contact between the exterior of the valve assembly and the degradable barrier; and the second tubular member being displaceable by application of a fluid flow in the inner passage at a hydraulic pressure that is sufficient to cause the tubular valve to shift from the port-closed position to the port-open position, the degradable barrier in the port-open position being exposed to and contacted by fluid to the exterior of the valve assembly causing the degradable barrier to gradually degrade for a delay period during which the applied fluid flow in the inner passage can be controlled without regard to the fluid flow to the exterior of the tubular valve system, and upon disintegration of the degradable barrier a fluid communication is established between the exterior of the valve assembly and the inner passage.

[0033] Other features and advantages of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description, while indicating preferred embodiments of the present disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The disclosure is in the hereinafter provided paragraphs described in relation to its figures. The figures provided herein are for illustration purposes and are not intended to limit the present disclosure. Like numerals designate like or similar features throughout the several views possibly shown situated differently or from a different angle. Thus, by way of example only, part 215 in FIG. 2 and FIG.
3A refers to a tubular string in both of these figures.

[0035] FIG. 1 is a schematic view of an example configuration of a well arrangement.

[0036] FIG. 2 is schematic view of an example configuration of a portion of a well arrangement having a wellbore string with shiftable tubular valve assemblies in accordance with the teachings herein.

[0037] FIG. 3A is an elevated side view of a shiftable valve in a first state.

[0038] FIG. 3B is a cross-sectional view of a shiftable valve attached to a wellbore string and installed in a wellbore section, shown in the same state as in FIG. 3A.

[0039] FIG. 3C is an enlarged cross-sectional view of the area marked 3C in FIG.
3B.

[0040] FIG. 4A is an elevated side view of a shiftable valve in a second state.

[0041] FIG. 4B is a cross-sectional view of a shiftable valve attached to a wellbore string and installed in a wellbore section, shown in the same state as in FIG. 4A.

[0042] FIG. 4C is an enlarged cross-sectional view of the area marked 4C in FIG.
4B.

[0043] FIG. 5A is an elevated side view of a shiftable valve in the second state after the degradable barrier has disintegrated.

[0044] FIG. 5B is a cross-sectional view of a shiftable valve attached to a .. wellbore string and installed in a wellbore section, shown in the same state as in FIG. 5A.

[0045] FIG. 5C is an enlarged cross-sectional view of the area marked 5C in FIG.
5B.

[0046] FIG. 6 is a schematic view of an example configuration of a portion of a well arrangement.

[0047] FIGS. 7A, 7B, 7C, and 7D are schematic overviews of example configurations of portions of a well arrangement.

[0048] The figures together with the following detailed description make apparent to those skilled in the art how the disclosure may be implemented in practice.
DETAILED DESCRIPTION OF THE DISCLOSURE

[0049] Various apparatuses and processes will be described below to provide an example of an embodiment of each claimed subject matter. No embodiment described below limits any claimed subject matter, and any claimed subject matter may cover any apparatuses, assemblies, methods, processes, or systems that differ from those described below. The claimed subject matter is not limited to any apparatuses, assemblies, methods, processes, or systems having all of the features of any apparatuses, assemblies, methods, processes, or systems described below or to features common to multiple or all of the any apparatuses, assemblies, methods, processes, or systems below. It is possible that an apparatus, assembly, method, process, or system described below is not an embodiment of any claimed subject matter. Any subject matter disclosed in an apparatus, assembly, method, process, or system described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors, or owners do not intend to abandon, disclaim, or dedicate to the public any such subject matter by its disclosure in this document.

[0050] All publications, patents, and patent applications referenced herein are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

[0051] Several directional terms such as "above", "below", "lower", "upper", "inner", and "outer" are used herein for convenience, including for reference to the drawings. In general, the terms "upper", "above", "upward", "uphole", "proximal", and similar terms are used to refer to a direction towards the earth's surface along the wellbore, while the terms "lower", "below", "downward", "downhole", and "distal"
are used to refer to a direction generally away from the earth's surface along the wellbore. The terms "inner" and "inward" are used herein to refer to a direction that is more radially towards the central longitudinal axis of a tubular component, while the terms "outer" and "outward" refer to a direction that is more radially away from the central longitudinal axis of a tubular component.

[0052] As used herein, the wording "and/or" is intended to represent an inclusive-or. That is, "X and/or Y" is intended to mean X or Y or both, for example. As a further example, "X, Y, and/or Z" is intended to mean X or Y or Z or any combination thereof.

[0053] It will be understood that any range of values described herein is intended to specifically include any intermediate value or sub-range within the given range, and all such intermediate values and sub-ranges are individually and specifically disclosed (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof that are modified by the term "about" are presumed to include a variation of up to a certain amount of the number to which reference is being made if the end result is not significantly changed, such as 1%, 2%, 5%, or 10%, for example.

[0054] It will also be understood that the word "a" or "an" is intended to mean "one or more" or "at least one", and any singular form is intended to include plurals herein, unless expressly specified otherwise.

[0055] It will be further understood that the term "comprise", including any variation thereof, is intended to be open-ended and means "included, but not limited to", unless otherwise specifically indicated to the contrary.

[0056] In general, the valve assembly of the present disclosure can be used to operate a well in a reservoir of hydrocarbons. Notably, the assembly of the present disclosure permits control of the flow path of fluids in a well. In particular, the valve assembly can be used to establish fluid communication between defined sections within a wellbore and portions of a hydrocarbon reservoir formation surrounding these sections.

[0057] In broad terms, the valve assembly of the present disclosure can be inserted in a wellbore string and shifted from a port-closed position to a port-open position to establish fluid communication between the inner passage of the valve and the exterior thereof, including the wellbore and surrounding rock formation.
One disadvantage of known valve systems is that high pressures can be required to hydraulically shift the valve to an open position. Upon shifting these known valve systems, the surrounding rock formation becomes exposed to high pressure differentials, for example 2,000 psi or more. This can be desirable in fracturing operations. However, such high-pressure differentials are problematic in enhanced recovery operations since the rock formation can be damaged, and perhaps more importantly, these pressure differentials can prevent or interfere with the establishment of a slowly migrating fluid front in the rock formation. The establishment of such a fluid front is required in an enhanced recovery operation to gradually displace hydrocarbon with fluid to thereby effect migration of residual hydrocarbon from the rock formation into the wellbore. In these operations, it is desirable to inject fluid at low pressures.

[0058] Furthermore, abrupt hydraulic pressure changes in the inner passage of the wellbore string can pose challenges for operators who wish to hydraulically control other components of the wellbore string, for example other valves or packers, upon having opened up the valve. This typically then requires operators to deploy mechanical tools, for example various shifting or setting tools, coupled to coiled tubing or a wire line from the surface to control these components, which can be a time consuming and expensive process.

[0059] By contrast, the valve assembly of the present disclosure can be operated so that only modest hydraulic pressure differentials between the inner wellbore string and the rock formation are established, for example 500 psi, or less.

However, the pressure applied for shifting the valve can be well in excess thereof.
This renders the valve assembly of the present disclosure particularly suitable for the extraction of residual hydrocarbon from a rock formation by flooding of the rock formation, i.e., gradual hydrocarbon displacement by fluids injected at low pressure, for example, following a high pressure fracturing operation. It is noted that in this regard, reference is made in the present disclosure to the phrase "a fluid flow having a hydraulic pressure sufficient to form a fluid-front", by which it is meant a fluid flow having a hydraulic pressure that is sufficient to form a more or less contiguous gradually migrating fluid front within a hydrocarbon bearing rock formation, for example, within a portion of a rock formation surrounding a valve, to displace hydrocarbons within the rock formation.

[0060] Furthermore, the valve assembly of the present disclosure can be hydraulically shifted without pressure changes in the inner passage for a period of time. During this time period, other components in the wellbore string may be controlled hydraulically, obviating the need for mechanical intervention.

[0061] Example embodiments are hereinafter described with reference to the drawings.

[0062] Referring to FIG. 1, shown therein is an example well arrangement 100 for fracturing an oil or gas reservoir formation 105. A rig 110 is set up at surface 120 for operating well 130. Rig 110 can initially be a drilling rig and can later be representative of well operation equipment, such as fracturing, cementing, stimulation fluid treatment, or acidizing equipment at selected times. For simplicity, any type of surface rig or tool deployment rig, including a mobile rig, such as a truck, can be represented by rig 110.

[0063] Well 130 comprises a vertical well section 140 and a horizontal well section 150. In operation, rig 110 can be used to apply fluids, for example, stimulation fluids, through the vertical section 140 of the well 130 to the reservoir formation 105 surrounding the horizontal section 150 of the well 130. The valve assemblies of the present disclosure can be deployed from rig 110, and permit control over the application location where fluid is applied in the well 130, including in the horizontal section 150 of well 130 and selected portions of reservoir formation 105.

[0064] Referring now to FIG. 2, shown therein in further detail (relative to FIG. 1), is a portion of an example well arrangement 200 for fracturing an oil or gas reservoir formation, known as an open hole wellbore system. The shown portion of the wellbore system 200 comprises a wellbore 202 defined by a wellbore wall 204 drilled into the reservoir formation 205 and having a proximal end p extending to the surface (not shown), and a distal end d extending to the end (not shown) of the wellbore 202. A tubular string 215 having an inner bore 216 inserted in the wellbore 202 forms an axially extending annulus 210 between the wellbore wall 204 and the tubular string 215. The tubular string 215 includes a plurality of spaced apart shiftable tubular valve assemblies 220a, and 220b (of which the exterior view is shown in FIG. 2), which will be described hereinafter in further detail.
Each valve assembly 220a and 220b comprises several side ports (not visible) which can be exposed to allow fluid communication between the tubular string 215 and the reservoir formation 205 via the annulus 210. A source to provide fluid and control fluid circulation can be set up at proximal end p of the well 130 so that fluid flows within the tubular string 215, as indicated by arrow F towards distal end d of the tubular string 215, whence fluid can flow into the annulus 210. Although two shiftable tubular valve assemblies 220a, and 220b are shown, more or fewer tubular valve assemblies may be used in practice. Thus, in some embodiments, 10, 20, 30, 40, 50, or more tubular valve assemblies may be used.

[0065] To provide zonal isolation, tubular isolating elements 230, 232, 234 are placed at the proximal and distal ends of each valve assembly 220a and 220b, so as to create fluid flow barriers between each valve assembly 220a and 220b and the surface. The tubular isolating elements 230, 232 and 234 can be packers, cup seals, or other isolation devices. Once the tubular string 215 is run into the wellbore 202 and placed in the desired position, the tubular isolating elements 230, 232, and 234 can be set to provide a substantially fluid tight seal between the wellbore wall 204 and the exterior of the tubular string 215, as will be understood by those of skill in the art. Once the valve assembly 220a or 220b is opened and fluid is permitted to flow from the inner bore 216 to the annulus 210, the fluid and pressure is contained to the area between the isolating elements, for example, between tubular isolating elements 230 and 232, or between tubular isolating elements and 234. Fluid treatment can then be concentrated on portions of the rock formation 205 between these pairs of isolating elements. By this method, different portions of the formation 205 can be subjected to a desired treatment regimen, for example, certain types and/or amounts of fluids and certain pressures that need not be the same for each valve assembly. Thus, for example, the portion 205a of the rock formation 205 between tubular isolating elements 230 and 232 may be treated differently than the portion 205b between tubular isolating elements and 234. The spacing, number, and placement of the tubular isolating elements 230, 232, and 234, and valves 220a and 220b can vary and can be determined by one skilled in the art, for example, a completions engineer familiar with the described open hole wellbore systems.

[0066] In at least one embodiment, the wellbore 202 has an outer diameter of 4.5 inches and an inner diameter of 4 inches, such that the wellbore wall 204 has a thickness of 0.25 inches. The tubular string 215 has an outer diameter of 3 inches and an inner diameter of 2 inches, such that the wall of the tubular string 215 has a thickness of 0.5 inches. Accordingly, the inner bore 216 has a diameter of 2 inches. The annulus 210 formed therefrom has an wellbore inner diameter of 4 inches and a tubular string outer diameter of 3 inches. The valve assemblies 220a and 220b have an outer diameter of slightly less than 4 inches at their widest parts such that the outer portions of the valve assemblies 220a and 220b are located adjacent to the inner portion of the wellbore wall 204. The tubular isolating elements 230, 232, and 234 when installed have an outer diameter of 4 inches such that at their widest parts the outer portions of the tubular isolating elements 230, 232, and 234 are in contact with the wellbore wall 204. It will be appreciated that this embodiment has been provided for illustration purposes only, and that other dimensions and proportions may be more suitable in different circumstances.

[0067] In some embodiments, inner bore 216 of the valve assemblies has a diameter of from about 1 inch to about 4 inches, and the length between proximal end p1 and distal end dl of the valve assemblies is from about 10 inches to about 20 inches.

[0068] In another example well implementation (not shown), the wellbore system can be a cemented wellbore system. In such a system, cement is used to form a lining for the wellbore prior to fluid treatment of the rock formation.

[0069] In further well implementations (not shown), the wellbore or certain sections thereof, can be lined with casing, in which an annulus is formed between the wellbore string and the casing.

[0070] It is noted that in the well assembly 200, in addition to including the shiftable valve assemblies 220a and 220b, which typically serve to interconnect two pieces of tubing, the tubular string 215 of the wellbore system further can include additional tools, including, without limitation, additional isolating elements capable of sealing the annulus 210 between the tubular string 215 and the wellbore wall 204, and other valves. As will be appreciated by those skilled in the art, such additional isolating elements and other valve assemblies can also be spaced in various ways relative to one another to achieve a desired interval length or number of ports per interval. In addition, well assemblies can include several other operational devices, including, for example, cementing tools (not shown), and/or a wellbore isolation valve (not shown), as is known by those skilled in the art.
As further will be appreciated by those of skill in the art, these tools may be operable from the surface.

[0071] In general, the valve assemblies 220a and 220b are deployed as part of the tubular string 215 to control fluid flow therethrough. In particular, the valve assemblies 220a and 220b can be deployed to control the opening of ported intervals through the tubular string 215 and are each operable from a port-closed position to a port-open position wherein fluid flow is permitted through the ports either from or to the surrounding reservoir formation 205. In general, the valve assemblies 220a and 220b can be actuated, causing one or more of the valve assemblies 220a and 220b to shift from a port-closed position to a port-open position. Conveniently, the valves assemblies 220a and 220b of the present disclosure can be hydraulically actuated through a hydraulic actuation member.
In an example embodiment, the hydraulic actuation member can include a vent 222a and 222b, which will hereinafter be described in further detail. In some embodiments, a single actuation can open a plurality of valves in a wellbore string.
In other embodiments, a first actuation can open a first valve in a wellbore string, and a second actuation can open a second valve in a wellbore string. Valve assemblies 220a and 220b are constructed in such a manner that upon shifting, fluid cannot immediately flow from the inner bore 216 of the tubular string through the ports into the annulus 210. Instead, for a certain period of time, herein termed a "delay period", the fluid flow within the inner bore 216 of the tubular string 215 remains controllable without regard for the fluid flow in the annulus 210 or the reservoir formation 205. Upon expiration of the delay period, fluid can flow through the port to the annulus 210 and contact reservoir formation 205. Furthermore, conversely, upon expiration of the delay period, fluid can flow from the reservoir formation 205 to the annulus 210 into the inner bore 216 of the tubular string 215.

[0072] The tubular string 215, including the valve assemblies 220a and 220b, and optionally other operational devices, can be run in and installed in the wellbore 202 typically with each of the valve assemblies 220a and 220b, in a port-closed position. The valve assemblies 220a and 220b can be shifted into their port-open position when the tubular string 215 is ready for use and ready for fluid flow to or from the reservoir formation 205.

[0073] It should be clearly understood that the valve assembly and methods of the present disclosure are not limited in any way to use in conjunction with the example well arrangements 100 and 200 shown in FIG. 1 and FIG. 2, respectively.
On the contrary, a wide variety of wellbore arrangements and configurations having a requirement for directing fluid in a wellbore can be constructed, and at least one tool assembly of the present disclosure and at least one process of the present disclosure can be used in conjunction with these wellbore arrangements and configurations.

[0074] According to one example embodiment of the present disclosure, well arrangements, such as the well arrangements 100 and 200, can, in one embodiment, be operated as illustrated in FIGS. 3A-3C, 4A-4C, and 5A-5C. In general overview, in FIGS. 3A-3C, a valve assembly 220a is shown in an initial port-closed position. In FIGS. 4A-4C, the valve assembly 220a is shown in a port-open position with a degradable barrier 360 in place. In FIGS. 5A-5C, the valve assembly 220a is shown in a port-open position following disintegration of the degradable barrier 360. It is noted that side views of the valve assembly 220a are shown in FIGS. 3A, 4A, and 5A, while cross sections of the valve assembly 220a are shown in FIGS. 3B, 3C, 4B, 4C, 5B, and 5C.

[0075] As shown in FIGS. 3A-3B, initially a tubular string 215 having an inner bore 216 comprising a valve assembly 220a in a port-closed position can be run into a wellbore 202 within a reservoir formation 205 and installed, to achieve, for example, a well arrangement as depicted in FIG. 2. The downhole depth may be selected as desired. In at least one embodiment, the downhole depth location of the valve assembly 220a within the wellbore 202, relative to the surface, can generally be established by measuring the length of the section of wellbore liner between a valve assembly or other known equipment and the surface, or other known methodologies may be used.

[0076] The axially extending valve assembly 220a has a distal end dl and a proximal end p1. Valve assembly 220a is constructed to have a first tubular member 305 and a second tubular member 310 collectively forming an inner valve bore 302 axially extending from and to the inner bore 216 of the tubular string 215.
The first tubular member 305 has threads 340 on an inner surface of its proximal end portion. The first tubular member 305 is proximally coupled to the tubular string portion 215a via the threads 340. Likewise, the first tubular member 305 has threads 341, on an inner surface of its distal end portion. Distally first tubular member 305 is coupled to a tubular extension member 375, 375b via the threads 341 and further secured via set screws 342 and 343 which can be accessed for assembly and disassembly purposes from the exterior of the valve assembly 220a via apertures 346 and 347. In turn, tubular extension member 375, 375b is distally coupled to the tubular string portion 215b. It is noted that the distal portion 375b of tubular member 375 is not shown as a cross section, but rather as a side view, hence the coupling thread is not shown.

[0077] The second tubular member 310 is coupled to the first tubular member 305 via shear pins 315 and 316. Furthermore, a support member 395, which is exterior of and coupled to the first tubular member 305 via threads 343 and set screws 368 and 369, separates a portion of the first tubular member 305 and the second tubular member 310, and furthermore the support member 395 provides support to the second tubular member 310. Various seal members, such as 0 rings 330, 331, 332, 333, and 334, ensure that in the closed position of the valve assembly 220a shown in FIGS. 3A-3B, there is no fluid contact between the inner valve bore 302 and the exterior wellbore 202.

[0078] The valve assembly 220a further includes an interior actuation aperture 355 through an inner surface of the first tubular member 305, shown in detail in FIG. 3C, which represents a fluid communication between the inner valve bore and compartment 365. It is noted that a single actuation aperture 355 is shown;
however, in other embodiments, 2, 3, 4, 5, or more actuation apertures may be included. Further apertures included are vent apertures 385 and 386 through the second tubular member 310, which represent fluid communication between the exterior of the valve assembly 220a (i.e., the annulus 210) and vent compartment 387 that is formed between an outer surface of the first tubular member 305 and an inner surface of the second tubular member 310.

[0079] In addition to being separated by the support member 395, the first tubular member 305 and second tubular member 310 are also separated by a degradable barrier 360, which is disposed between the first tubular member 305 and the second tubular member 310 at a proximal portion of the second tubular member 310 and covers port apertures 398 and 399. In the shown embodiment, the degradable barrier 360 is annularly shaped and radially exteriorly disposed relative to the first tubular member 305. In other embodiments, the degradable barrier can have different geometrical shapes, or it can be constructed out of separate degradable barrier elements. For example, in embodiments where multiple ports are included, each port can be covered by a separate degradable barrier element.
In the closed position shown in FIGS. 3A-3B, the degradable barrier 360 is not in fluid contact either from the exterior or from the interior. In the shown embodiment, plugs 381 and 382 (further shown in FIG. 4C and described hereinafter) are located in channels in the first tubular member 310 and are radially disposed between the inner bore 302 and the degradable barrier 360 to prevent fluid contact from the interior, and portions of the second tubular member 310 cover the degradable barrier 360 to prevent fluid contact from the outside of the valve assembly 220a. Interior fluid contact in other embodiments may be prevented using, for example, a surface coating or a wax seal.

[0080] Side ports in the tubular valve assemblies of the present disclosure can be implemented in various ways. In general, side ports are apertures in the wall of the tubular valve assembly that allow for fluid communication between the central inner passage of the tubular valve assembly and the exterior of the tubular valve assembly. In different embodiments, the number of ports can vary. For example, in different embodiments, the shiftable valve 220a can have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more side ports. Furthermore, the geometry of the ports can vary. Ports can, for example, have an oval shape, or in other embodiments, have a round shape (see e.g.: 505 in FIG. 5A). Radially extending port apertures can also be shaped in different geometries. In some embodiments, the port apertures are cylindrically or octahedrally shaped. In other embodiments, the ports can have walls that radially narrow gradually or incrementally (in one or more increments). By way of example, referring to the enlarged cross sections FIG. 4C (the degradable barrier covered) and FIG. 5C (the ports are open as the degradable barrier has disintegrated), in one embodiment, port aperture 398 contains a single incrementally inwardly radially narrowing portion 446 with a wider exterior portion and a narrower interior portion. Different port aperture designs can be used to achieve different fluid flows through the ports. Thus, for example, an inwardly radially narrowing port design such as that shown in FIG. 4C and FIG. 5C will result in a reduced fluid flow through the port aperture 398 relative to a port without narrowing portion 446.

[0081] The degradable barrier 360 can be fabricated from any degradable materials, including for example polyvinyl alcohol-based materials, polyglycolic acid-based materials, polylactide polymer-based materials, or alloyed materials, such as magnesium or aluminum-based materials, or combinations of any of the foregoing. Materials can further be selected to react at relatively low wellbore temperatures, for example as low as 50 C, and materials can be selected so that they react with fresh water exhibiting low chloride concentrations. In this respect, materials consisting primarily of magnesium and aluminum are deemed particularly suitable. In more general terms, degradable materials can be any materials that can chemically react with one or more fluids that can be present in a wellbore, including for example water, a stimulation fluid, a proppant slurry, an acid, or a base, in a manner that results in degradation and subsequent disintegration of the material in a relatively brief time period, for example, a delay period of less than about 1 month, or less than about 1 week. In some embodiments, degradation can be even faster, for example, a delay period of less than about 72 hours, less than about 48 hours, less than about 36 hours, less than about 24 hours, less than about 12 hours, less than about 6 hours, less than about 3 hours, less than about 1 hour, less than about 30 minutes, or from about 1 hour to about 48 hours.

[0082] The delay period provides for at least two operational advantages.
First, the pressure initially used to open the valve can, during the delay period, be reduced by reducing the fluid flow from the surface. At reduced pressures, it is possible to inject fluid into the rock formation surrounding the valve assembly and form a fluid front to displace hydrocarbons and capture these in the well. It should be noted that such a fluid injection operation is different from a fracking operation, in that the rock formation at these pressures is not fractured, but rather fluid within the rock formation is displaced. Second, during the delay period, other hydraulically controllable tools present in the string can continue to be controlled.

[0083] In the closed position shown in FIGS. 3A-3B, the valve assembly 220a can be installed in the wellbore 202 in a manner in which there is no fluid communication between the inner bore 302 of the valve assembly 220a or the inner bore 216 of the tubular string 215, on the one hand, and the annulus 210 or surrounding rock formation 205, on the other hand. Therefore, the degradable barrier 360 in this closed position is not subject to degradation.

[0084] Turning now to FIG. 3C, in conjunction with FIG. 3A and FIG. 3B, in order to shift the valve assembly 220a from a port-closed position to a port-open position, a fluid flow can be established from the surface through the inner bore 216 of the tubular string 215 and the inner bore 302 of the valve assembly 220a. The fluid flow can exert fluid pressure (PR) via actuation aperture 355 on to the second tubular member 310. Upon the exertion of sufficient fluid pressure, shear pins and 316 are sheared, and the second tubular member 310 can move in a distal direction relative to the first tubular member 305. It is noted that fluid present in vent compartment 387 in the movement of the second tubular member 310 is displaced and can escape via the vent apertures 385 and 386. It is further noted that the fluid flow may be selected to have hydraulic pressures as desired, provided the hydraulic pressure is sufficient to shear the shear pins 315 and 316, and subsequently shift the second tubular member 310 in the distal axial direction relative to the first tubular member 305. In some embodiments, the fluid flow can be selected to have a hydraulic pressure substantially in excess of the hydraulic pressure used to subsequently treat the rock formation surrounding the valve, as hereinafter further described. Thus, in some embodiments, hydraulic pressures used to shift the valve assembly 220a can be about 1,000 psi or more, about 1,500 psi or more, about 2,000 psi, about 3,000 psi or more, or about 4,000 psi or more, or from about 1,000 psi to about 4,000 psi, or, for example, from about 1,000 psi to about 3,000 psi.

[0085] As noted in general, hydraulic pressures can be selected to be sufficient to shear shear pins 315 and 316. Shear pins 315 and 316 in turn can be selected to be shearable within the pressure ranges set forth herein. Pressure gauges, generally known to those in the art, can be installed at surface 120, and pressure can be applied using a fluid pump, for example deployed by a pump truck, at surface using techniques generally known to those in the art. The applied pressures can be monitored and adjusted until a desired pressure is achieved, based on the pressure gauge readings.

[0086] Turning now to FIGS. 4A-4B, shown therein is the valve assembly 220a in a port-open position shortly following actuation and axial displacement of the second tubular member 310 in the distal direction. It is noted that the displacement of the second tubular member 310 is stopped by displacement limiting surface that is located on an exterior surface of the tubular member 375.

[0087] Advantageously, displacement of the second tubular member 310 results in the exposure of degradable barrier 360 to the exterior of valve assembly 220a.
Thus, now contact is made between the fluid present in the annulus 210 and the degradable barrier 360, and thus degradation of the degradable barrier 360 is initiated. However, no fluid contact is made between the interior bore 302 of the valve assembly 220a and the exterior since the degradable barrier 360 covering port apertures 398 and 399, and the plugs 381 and 382, positioned radially interiorly relative to the barrier 360, prevent such contact. The port apertures 398 and 399 are located opposite one another on the first tubular member 305 near the proximal end portion of the first tubular member 305. In different embodiments, the plugs may have different shapes; however, they are shaped so as to sufficiently closely fit within the port aperture to prevent fluid contact between the interior bore and the degradable barrier. Thus, for example, cylindrical plugs may be used in conjunction with cylindrically shaped port apertures, as shown in FIGS. 4C and 5C, and octahedrally shaped plugs may be used in conjunction with octahedrally shaped port apertures.

[0088] It is further noted that during displacement of the second tubular member 310, compartment 365 volumetrically expands as a first surface of the flange portion of the tubular member 310 adjacent the compartment 365 moves away from the compartment 365 as the second tubular member 310 moves distally. At the same time, the volume of vent compartment 387 reduces until it is no longer substantially existent in the closed-port position shown in FIGS. 4A-4B (which is why the vent compartment 387 label does not appear in FIG. 4B). This is due to a second surface of the flange portion of the tubular member 310 adjacent the compartment 387 moving toward the compartment 387 as the second tubular member 310 moves distally. The first and second surfaces of the flange of the second tubular member 310 are opposite one another. Any fluid present in vent compartment 387 can escape to the exterior via vent apertures 385 and 386. In the shown embodiment, in a port-open position, set screws 342 and 343 are aligned with vent apertures 385 and 386, thus allowing access thereto from the exterior of the valve assembly 220a. Furthermore, as noted, shear pins 315 and 316 are sheared in the displacement of the second tubular member 310 leaving sheared shear pins 405 and 406, respectively.

[0089] As noted, upon exposure following displacement of the second tubular member 310 to a port-open position, degradation of the degradable barrier 360 is initiated. Such degradation starts from the outside in, and for a period of time (i.e., the delay period), the barrier 360 remains intact and there is no fluid communication between the annulus 210 and the inner valve bore 302, or vice-versa. Thus, during the delay period, fluid flow inside the inner bore 302 of the valve assembly 220a (i.e., the valve bore) can continue to be controlled without regard of the fluid flow and hydraulic pressure to the exterior of the valve assembly 220a. During the delay period, it is therefore possible, in one example embodiment, to hydraulically operate other components present on the tubular string 215, for example components distally located on the tubular string 215 relative to the valve assembly 220a, such as another valve assembly (not shown) or a packer (not shown). During the delay period, such tools can be hydraulically operated to cause a shift from a first operable position to a second operable position. Thus, for example, during the delay period, a hydraulically operable valve, for example, a valve located distally on the tubular string from valve assembly 220a, may be operated to shift from a port-closed position to a port-open position or vice-versa, or a hydraulically operable isolation element, such as a packer, may be operated to shift from a position where the isolating element forms a seal between a wellbore and a wellbore liner to another position in which the seal is broken, or vice-versa.

[0090] Turning now to FIGS. 5A-5B, shown therein is the valve assembly 220a, upon completion of degradation (i.e., disintegration) of the degradable barrier 360.
Plugs 381 and 382 have also been displaced, which can be achieved by applying a fluid flow at low hydraulic pressure to the valve bore 302. Referring now to FIGS.
4B-4C, again in conjunction with FIGS. 5A-5B. Plugs 381 and 382 in the current example embodiment are separate metal cylinders that carry seals 444 and 445 on their periphery to ensure a fluid tight seal against the walls of port apertures 398 and 399. Plugs 381 and 382 can provide protection to the degradable barrier 360 from the hydraulic pressure that is applied to shift the valve assembly 220a from a port-closed position to a port-open position. Thus, it is possible to apply fluid flows in the inner bore 216 of the tubular string 215 at hydraulic pressures well in excess of the pressures used to inject fluid into the rock formation following disintegration of the barrier 360. For example, shifting pressures (i.e., pressure required to actuate the shiftable valve assembly 220a from a port closed position to a port open position) may be in excess of 1,000 psi, in excess of about 1,500 psi, in excess of about 2,000 psi, in excess of about 3,000 psi, or in excess of about 4,000 psi, or for example from about 1,000 psi to about 3,000 psi. Once the degradable barrier 360 has disintegrated, fluid flows applied from the valve bore 302 can displace the plugs 381 and 382 radially outward into the space previously occupied by the degradable barrier 360 and the second tubular member 310.
Fluid (F) can flow from the interior of the valve bore 302 through the incrementally narrowing portion 446 (see: FIG. 5C) and wider portion of the port apertures and 399 into the annulus 210, or vice-versa. Plugs 381 and 382 can be made of any material suitable for operation under wellbore conditions, or they may be optional. Thus, for example, in one embodiment, plugs may absent, and the degradable barrier may be protected from degradation by fluids in the valve interior by a surface coating applied to the interiorly disposed surface area of the degradable barrier. Upon disintegration of the barrier, the surface coating will break as fluid pressure is applied.

[0091] The shiftable valve assembly of the present disclosure is particularly useful to fluid-treat a rock formation using fluid flows at modest hydraulic pressures, notably fluid flows at hydraulic pressures sufficient to form a fluid-front to thereby displace hydrocarbons from a hydrocarbon bearing rock formation.
This is because after a higher hydraulic pressure is used to expose a degradable barrier so that the degradable barrier disintegrates, fluid flows at lower hydraulic pressures can be used to interact with the hydrocarbon formation. Fluid flows at hydraulic pressures sufficient to a form a fluid-front include pressures less than about 1,000 psi; less than about 750 psi; less than about 500 psi; less than about 400 psi; less than about 300 psi; less than about 200 psi; and less than about 100 psi; or from about 100 psi to about 1,000 psi. Under such hydraulic pressures, fluid can migrate through a rock formation surrounding at a volumetric flow rate of, for example, from about 20 m3/day to about 120 m3/day. In this manner, the shiftable valve assembly may be implemented according to effect a fluid flow in a hydrocarbon bearing rock formation disclosure as further illustrated in an example embodiment in FIGS.

7D.

[0092] Referring now to FIGS. 7A-70, shown therein is an example well configuration 700 including a wellbore 709 having a proximal end p and distal end d and a zone 701 in the hydrocarbon bearing rock formation 205 identified for low pressure fluid treatment. Following the establishment of fluid communication between the tubular string 715 and the rock formation 205, operating a valve assembly 220 as hereinbefore described, a fluid flow (F) having a hydraulic pressure sufficient to form a fluid-front can be set up at surface 707. The fluid flow F can exit the valve assembly 220 to establish a migrating and expanding fluid front 702 within the treatment zone 701 of rock formation 205. As the fluid front 702 migrates outward in a more or less radial direction into the rock formation 205 surrounding the valve 220, the fluid front 702 displaces hydrocarbons present in the treatment zone 701, allowing a hydrocarbon flux to develop, including a hydrocarbon flux (H) towards the wellbore 709. The hydrocarbons entering the wellbore 709 may be recovered at surface 707.

[0093] In another aspect, the present disclosure relates to processes for controlling fluid flow in a subterranean well. Accordingly, the present disclosure further provides, in one broad aspect, in at least one example embodiment, a process for controlling fluid flow in a tubular string (also referred to as a wellbore string), the process comprising: installing a tubular string 215 in a wellbore and applying fluid flows to the inner bore 216 of the tubular string 215.

[0094] The process begins with installing a tubular string 215 in a wellbore 202.
The tubular string 215 has an inner bore 216 (also referred to as a central bore) therethrough and includes a shiftable tubular valve assembly 220 (also referred to as a side-ported two member tubular valve assembly) interconnecting two successive portions of the tubular string 215. The valve assembly 220 has a first tubular member 305 (which has a port) and a second tubular member 310. The valve assembly 220 is shiftable from a port-closed position to a port-open position and has a fluid degradable barrier 360 covering the port. The degradable barrier 360 is covered by the first tubular member 305 in the port-closed position to prevent fluid contact between the exterior of the valve assembly 220 and the degradable barrier 360.

[0095] The process continues with applying fluid flows to the inner bore 216 at sufficient hydraulic pressures to cause changes to the valve assembly 220.
These various pressures can be determined experimentally or by mounting sensors at locations of the valve assembly 220 to confirm that the changes have occurred.

One change is to cause the valve assembly 220 to shift from the port-closed position to the port-open position. Another change is to expose the degradable barrier 360 to the exterior of the valve assembly 220 to permit fluid contact between the degradable barrier 360 and fluid to the exterior of the valve assembly 220.
Another change is to degrade the degradable barrier 360 during a delay period until the degradable barrier 360 is disintegrated. Another change is to establish fluid communication between the inner bore 216 and the exterior of the valve assembly 220 when the degradable barrier 360 is disintegrated.

[0096] In at least one embodiment, the process can further include applying a first fluid flow at a first hydraulic pressure sufficient to cause the valve assembly 220 to shift from the port-closed position to the port-open position, and then applying, after the degradable barrier 360 has disintegrated, a second fluid flow at a second hydraulic pressure to establish fluid communication between the inner bore 216 and the exterior of the valve assembly 220.

[0097] In at least one embodiment, the second fluid flow at the second hydraulic pressure can further be sufficient to form a fluid-front in a hydrocarbon-bearing rock formation surrounding the valve assembly 220 to displace hydrocarbons from the rock formation into the wellbore 202.

[0098] In at least one embodiment, the first hydraulic pressure can be higher than the second hydraulic pressure.

[0099] In at least one embodiment, the first hydraulic pressure can be in excess of about 1,000 psi, in excess of about 1,500 psi, in excess of about 2,000 psi, in excess of about 3,000 psi, or in excess of about 4,000 psi, and the second hydraulic pressure can be less than about 1,000 psi; less than about 750 psi;
less than about 500 psi; less than about 400 psi; less than about 300, psi; less than about 200 psi; or less than about 100 psi.

[00100] In at least one embodiment, the process can further include, during the delay period, hydraulically shifting at least one other hydraulically controllable component installed on the tubular string 215 together with the valve assembly 220 from a first operable position to a second operable position.

[00101] In at least one embodiment, the tubular string 215 comprises two or more of the side-ported valve assemblies of the present disclosure separated from one another by a portion of the tubular string 215, for example, 3, 4, 5, 6, 7, 8, 9, 10, or more side-ported valve assemblies. The process can then further include applying fluid flow at a sufficient pressure to the inner bore 216 to cause each of the two or more side-ported valve assemblies to shift from the port-closed to the port-open position. Such shifts may be effected more or less simultaneously, or sequentially.
In one embodiment, in which a first and second shift are effected sequentially, a first shift may result in a first valve assembly 220a to be shifted from a port-closed position to a port-open position, and following disintegration of the degradable barrier 360 (and the concomitant expiration of the delay period) of the first valve assembly 220a, a second shift may result in a second valve assembly 220b to be shifted from a port-closed position to a port-open position.

[00102] In at least one embodiment, the tubular string 215 can be installed in a wide-diameter tubular string 620, which is another, larger diameter wellbore string.

[00103] In at least one embodiment, the wide-diameter tubular string 620 includes other side-ported valves 615, and upon establishing fluid communication between the inner bore 216 and the valve assembly 220, further fluid communication is established between the valve assembly 220 and the wellbore 202 via the side ports of the other side-ported valves 615.

[00104] Turning to FIG. 6 now, shown therein is an example well arrangement 600. Well arrangement 600 contains a wellbore 605 in which has been installed a wide-diameter tubular string 620. The wide-diameter tubular string 620 contains a side-ported valve 615. The side-ported valve 615 may have been used to fracture rock formation 205 and extract hydrocarbon from the rock formation 205. Upon having completed the hydrocarbon recovery from the fracturing operation, the ports 610 of the side-ported valve 615 were left in a port-open position;
alternatively, the ports 610 were left in a port-closed position and are now opened.
In order to perform an enhanced recovery operation, a narrow-diameter tubular string 625 can be installed inside the wide-diameter tubular string 620. The narrow-diameter tubular string 625 contains the valve assembly 220 of the present disclosure. In some embodiments, the narrow-diameter tubular string 625 can be inserted in such a manner that the valve assembly 220 is positioned in close proximity to the side-ported valve 615, for example so that the valve assembly and the side-ported valve 615 are spaced apart less than about 10 meters, less than about 5 meters, or less than about 2 meters from one another. This may be achieved in particular when it is known where in the wellbore 605 (i.e., at what depth) the side-ported valve 615 is located, for example, based on information relating to the prior fracturing operation for which the side-ported valve 615 was used. The narrow-diameter tubular string 620 can then be designed to include the valve assembly 220 at a position within the narrow-diameter tubular string 620, so that the narrow-diameter tubular string 620 can be inserted in a manner that allows valve assembly 220 to become positioned in close proximity of the side-ported valve 615. Accordingly, the insertion can then be performed using a methodology that allows the determination of the depth of the side-ported valve 615 to be made, for example, by measuring the length of the section of wellbore liner between valve assembly 615 and the surface, or using other known methodologies.

[00105] In another embodiment, the narrow-diameter tubular string can be inserted within the wide-diameter tubular string so that upon completion of the insertion, the valve assembly 220 is not located distally or proximally relative to the side-ported valve 615, but instead is inserted therein.

[00106] The valve assembly 220 can then be actuated and shifted from a port-closed position to a port-open position as hereinbefore described. Upon disintegration of the fluid degradable barrier (not shown) of the valve assembly 220, a low-pressure fluid flow can be established from the surface through the side ports (not shown) of valve assembly 220 and the ports 610 of side-ported valve 615, and a fluid-front can be formed within rock formation 205 surrounding the side-ported valve 615. Displacement of the hydrocarbon results in flow of the hydrocarbon to the wide-diameter tubular string 620 and narrow diameter tubular string 625 whence the hydrocarbon can be recovered at surface.

[00107] In further different embodiments, the wide-diameter tubular string 620 can include a plurality of side-ported valves 615, and the narrow-diameter tubular string 625 can contain a corresponding plurality of valve assemblies 220 that each interact with one of the side-ported valves 615. In some embodiments, upon installation of the narrow-diameter tubular string 625, two or more valve assemblies 220 may be spaced closely to two or more side-ported valves 615, and different zones of the rock formation 205 may be treated sequentially as hereinbefore described.

[00108] As can now be appreciated, the various embodiments of the valve assembly described herein can be conveniently used to control fluid flow in wells by using modest pressure levels to provide enhanced hydrocarbon recovery and, optionally to hydraulically control other components in a wellbore. The various .. embodiments of the valve assembly described herein can be applied in various oil or gas extraction processes.

[00109] The above disclosure generally describes various aspects of various example embodiments of apparatuses and processes of the present disclosure. It will be appreciated by a person skilled in the art having carefully considered the above description of representative example embodiments of the present disclosure that a wide variety of modifications, amendments, adjustments, substitutions, deletions, and other changes may be made to these specific example embodiments, without departing from the scope of the present disclosure.
Accordingly, the foregoing detailed description is to be understood as being given by way of example and illustration only, the spirit and scope of the present disclosure being limited solely by the appended claims.

Claims (24)

1. A tubular valve assembly for directing and controlling fluid flow in a wellbore, the valve assembly comprising:
a first tubular member having a port through a wall of the first tubular member, the port being covered by a fluid degradable barrier; and a second tubular member located exteriorly to the first tubular member and displaceable relative to the first tubular member from a port-closed position to a port-open position;
the second tubular member being arranged so that in a port-closed position there is no fluid communication from an exterior of the valve assembly to an inner passage of the first tubular member through the port, and the second tubular member covers the degradable barrier to prevent fluid contact between the exterior of the valve assembly and the degradable barrier; and the second tubular member being displaceable by application of a fluid flow in the inner passage of the first tubular member at a hydraulic pressure that is sufficient to cause the second tubular valve to shift from the port-closed position to the port-open position, the degradable barrier in the port-open position being exposed to and contacted by fluid to the exterior of the valve assembly causing the degradable barrier to gradually degrade for a delay period during which the applied fluid flow in the inner passage can be controlled without regard to an exterior fluid flow that is exterior of the valve assembly, and upon disintegration of the degradable barrier a fluid communication is established between the exterior of the valve assembly and the inner passage.

2. The valve assembly according to claim 1, wherein the valve assembly comprises a hydraulic actuation member.

3. The valve assembly according to claim 2, wherein the hydraulic actuation member comprises an actuation aperture forming a second fluid communication between the interior of the valve assembly and the second tubular member.

4. The valve assembly according to claim 1, further comprising a plug or a surface coating that is disposed between the degradable barrier and the inner passage of the first tubular member to protect the degradable barrier from degradation due to fluids in the inner passage of the first tubular member.

5. The valve assembly according to claim 4, wherein the plug is a cylindrical plug radially disposed between the inner passage of the first tubular member and the degradable barrier, and upon disintegration of the degradable barrier the plug member is radially exteriorly displaceable by the fluid flow through the inner passage of the first tubular member.

6. The valve assembly according to claim 1, wherein the port is an inwardly radially narrowing port.

7. The valve assembly according to claim 1, further comprising a shear pin that is arranged to couple the first tubular member to the second tubular member and during the application of the fluid flow in the inner passage of the first tubular member the shear pin is arranged to shear thereby allowing displacement of the second tubular member.

8. The valve assembly according to claim 1, wherein the delay period is sufficiently long to hydraulically shift at least one other hydraulically controllable component installed on a tubular string together with the valve assembly from a first operable position to a second operable position.

9. The valve assembly according to claim 8, wherein the delay period is from about 48 hours to about 1 hour.

10. The valve assembly according to claim 1, wherein fluid communication between the exterior of the valve assembly and the inner passage is established by a second fluid flow at a hydraulic pressure that is sufficient to form a fluid-front in a hydrocarbon bearing rock formation surrounding the valve assembly installed in the wellbore.

11. The valve assembly according to claim 10, wherein the hydraulic pressure is from about 100 psi to about 1,000 psi.

12. The valve assembly according to claim 10, wherein the hydraulic pressure that is sufficient to displace the second tubular member is larger than the hydraulic pressure that is sufficient to form a fluid-front in a hydrocarbon bearing rock formation.

13. A process for controlling fluid flow in a wellbore string, the process comprising:
installing a wellbore string in a wellbore, the wellbore string having a central bore therethrough and comprising a side-ported two member tubular valve assembly interconnecting two successive portions of the string, the tubular valve assembly being shiftable from a port-closed position to a port-open position, and having a fluid degradable barrier covering the port, the degradable barrier being covered by one of the tubular valve members in the port-closed position to prevent fluid contact between an exterior of the tubular valve and the degradable barrier; and applying fluid flows to the central bore at sufficient hydraulic pressures to:
cause the tubular valve assembly to shift from the port-closed position to the port-open position;
expose the degradable barrier to the exterior of the tubular valve assembly to permit fluid contact between the barrier and fluid to the exterior of the tubular valve assembly;
degrade the barrier during a delay period until the degradable barrier is disintegrated; and establish fluid communication between the central bore and the exterior of the tubular valve assembly when the degradable barrier is disintegrated.

14. The process according to claim 13, wherein the process further comprises applying a first fluid flow at a first hydraulic pressure sufficient to cause the tubular valve assembly to shift from the port-closed position to the port-open position, and then applying a second fluid flow at a second hydraulic pressure to establish fluid communication between the central bore and the exterior of the tubular valve assembly.

15. The process according to claim 14, wherein the second fluid flow at the second hydraulic pressure further is sufficient to form a fluid-front in a hydrocarbon-bearing rock formation surrounding the valve assembly to displace hydrocarbons from the rock formation into the wellbore.

16. The process according to claims 14 or 15, wherein the first hydraulic pressure is higher than the second hydraulic pressure.

17. The process according to claim 16, wherein the first hydraulic pressure is a pressure of from about 1,000 psi to about 4,000 psi, and the second hydraulic pressure is a pressure of from about 100 psi to about 1,000 psi.

18. The process according to claim 13, wherein the process further comprises, during the delay period, hydraulically shifting at least one other hydraulically controllable component installed on the tubular string together with the valve assembly from a first operable position to a second operable position.

19. The process according to claim 13, wherein the wellbore string comprises two or more of the side-ported valve assemblies separated from one another by a portion of the wellbore string, and wherein the process further includes applying fluid flow at a sufficient pressure to the central bore to cause each of the two or more side-ported valve assemblies to simultaneously or sequentially shift from the port-closed to the port-open position.

20. The process according to claim 19, wherein the process further includes applying fluid flow at a sufficient pressure to the central bore to cause each of the two or more side-ported valve assemblies to (i) shift from the port-closed to the port-open position;
(11) expose the degradable barrier in each of the valve assemblies to the exterior of the valve assemblies to permit fluid contact between the barriers and fluid to the exterior of the valve assemblies;
(iii) degrade the barriers during a delay period until the degradable barrier is disintegrated; and (iv) establish fluid communication between the central bore and the exterior of the tubular valve assemblies when the barriers are disintegrated; and wherein the performance of all of steps (i) to (iv) is completed for a first of the two or more side-ported valves before the performance of these steps is initiated in respect of a second of the two or more side-ported valves.

21. The process according to any one of claims 13 to 20, wherein the wellbore string is installed inside another larger diameter wellbore string.

22. The process according to claim 21, wherein the larger diameter wellbore string comprises an additional side-ported valve, and upon establishing fluid communication between the central bore and an exterior of the tubular valve assembly, further fluid communication is established between the tubular valve assembly and the wellbore by actuating the side ports of the additional side-ported valve.

23. The method according to claim 21, wherein the larger diameter wellbore string includes two or more other side-ported valves, and the process further includes upon establishing fluid communication between the central bore and an exterior of the tubular valve assembly, establishing fluid communication between the tubular valve assembly and the wellbore by actuating the side ports of the two or more other side-ported valves.

24. A use of a tubular valve assembly to establish a contiguous fluid front in a hydrocarbon bearing rock formation to thereby displace the hydrocarbon from the rock formation into a wellbore, the assembly comprising:
a first tubular member having a port through a wall of the tubular member, the port covered by a fluid degradable barrier;
a second tubular member located exteriorly to the first tubular member and being displaceable relative to the first tubular member from a port-closed position to a port-open position;

the second tubular member further being arranged so that in the port-closed position there is no fluid communication from an exterior of the valve assembly to an inner passage of the first tubular member through the port, and the second tubular member covers the degradable barrier to prevent fluid contact between the exterior of the valve assembly and the degradable barrier; and the second tubular member being displaceable by application of a fluid flow in the inner passage at a hydraulic pressure that is sufficient to cause the tubular valve to shift from the port-closed position to the port-open position, the degradable barrier in the port-open position being exposed to and contacted by fluid to the exterior of the valve assembly causing the degradable barrier to gradually degrade for a delay period during which the applied fluid flow in the inner passage can be controlled without regard to the fluid flow to the exterior of the tubular valve system, and upon disintegration of the degradable barrier, a fluid communication is established between the exterior of the valve assembly and the inner passage.