Downhole Check Valve Assembly with a Swellable Element Mechanism

[0001] This section is intended to provide relevant background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.

[0002] Check valves and other floating equipment can be installed above ground within a pipe or casing and used during downhole operations, such as for controlling fluid flow. The check valve is installed into a segment of pipe which is later connected to the casing. The valve is assembled into this segment via concrete, resin, or even threading. Problems may be caused during the downhole operation if a check valve becomes unattached or slips from within the casing.

[0003] Therefore, there is a need for a check valve assembly that reliably maintains a gas-tight seal with the inner surface of the casing under relatively high pressures commonly experienced during downhole operations.

[0007] Valve systems and methods for inserting the valve system into a casing for a downhole environment and installing the casing in the downhole environment are provided. The valve system includes a mandrel, a check or flapper valve assembly, and a sealing element containing swellable polymeric material. The check valve assembly is coupled to the mandrel and operable to provide a fluid flow in a primary direction through a passageway of the mandrel and prohibit the fluid flow in a secondary direction through the passageway opposite of the primary direction. The sealing element is located on an outer surface of the mandrel. In some examples, the sealing element includes slip buttons located on the swellable polymeric material.

[0008] FIG. 1 depicts a schematic view of a well system 10 including a valve system 50 that is located in a casing 40 placed into a downhole environment, including a subterranean region 22 beneath the ground surface 20, according to one or more embodiments. The valve system 50 can be a check valve, a flapper valve, or another type of valve or flow control device. A string of pipes connected together form the casing 40 that is lowered into a wellbore 12.

[0009] The subterranean region 22 includes all or part of one or more subterranean formations, subterranean zones, and/or other earth formations. The subterranean region 22 shown in FIG. 1, for example, includes multiple subsurface layers 24. The subsurface layers 24 can include sedimentary layers, rock layers, sand layers, or any combination thereof and other types of subsurface layers. One or more of the subsurface layers 24 can contain fluids, such as brine, oil, gas, or combinations thereof. The wellbore 12 penetrates through the subsurface layers 24 and although the wellbore 12 shown in FIG. 1 is a vertical wellbore, the valve system 50 can also be implemented in other wellbore orientations. For example, the valve system 50 may be adapted for horizontal wellbores, slant wellbores, curved wellbores, vertical wellbores, or any combination thereof. The valve system 50 can be or include any of the valve systems and/or the check valve assemblies described and discussed below.

[0010] FIGS. 2A and 2B are schematic views of a valve system 100 with a swellable sealing element mechanism that can be positioned into a casing that is used in a downhole environment, according to one or more embodiments. The valve system 100 is insertable into the casing or pipe above ground and subsequently, the casing containing the installed valve system 100 is placed into a downhole environment, such as a borehole, a wellbore, a well, and/or a subterranean formation. Alternatively, the valve system 100 can be inserted into and attached inside the casing or pipe that is already positioned in a downhole environment.

[0011] The valve system 100 includes a mandrel 110, a setting system 120, and a check valve assembly 160. As depicted in FIG. 2B, the mandrel 110 includes an outer surface 111 and an inner surface 113. The inner surface 113 defines a passageway 112 extending or otherwise passing through the mandrel 110.

[0012] The check valve assembly 160 is coupled to the mandrel 110 and operable to provide a fluid flow 102 in a primary direction (depicted by arrows in FIG. 2B) through the passageway 112 and to prohibit the fluid flow 102 in a secondary direction (not shown) through the passageway 112 opposite of the primary direction. The check valve assembly 160 includes a valve body 162, a valve stem 163, a plunger 164, an actuator 166 (e.g., spring), and an engagement member 168. It should be appreciated that the check valve assembly 160 can include other or different components as well. Although the valve system 100 is depicted containing the check valve assembly 160, other types of valves, such as a flapper valve, can substituted for the check valve assembly 160.

[0013] As shown in FIG. 2B, fluid flowing along the path of the fluid flow 102 in the primary direction exerts sufficient pressure against the plunger 164 to overcome a force pressing the plunger 164 against the valve body 162. The force pressing the plunger 164 against the valve body 162 includes the actuator 166, as well as fluid pressure from outside of the casing produced from a flowing along a path in the secondary direction opposite of the fluid flow 102 in the primary direction. Whenever the pressure from inside the casing is less than the pressure outside of the casing, the actuator 166 and the outside pressure pushes the plunger 164 into sealing engagement with the valve body 162 therefore prohibiting fluid from flowing along the secondary direction.

[0014] The setting system 120 is located on the outer surface 111 of the mandrel 110 and includes a sealing element 130 and a plurality of gripping elements 140. In one or more embodiments, the sealing element 130 containing the swellable polymeric material circumscribes or encompasses at least a portion of or completely around the mandrel 110, as depicted in FIG. 2. In other aspects, the sealing element 130 containing the swellable polymeric material only partially encircles the mandrel 110 (not shown). The sealing element 130 has an inner surface 132 and an outer surface 134. The inner surface 132 of the sealing element 130 is located on the outer surface 111 of the mandrel 110. The gripping elements 140 are located on the outer surface 134 of the sealing element 130 and/or at least partially contained within the sealing element 130 and extending from the outer surface 134. For example, the gripping elements 140 can be located on and/or within the swellable polymeric material. The sealing element 130 forms a gas-tight seal when sealingly engaged with the inner surface of the casing.

[0015] The gripping elements 140 can be or include, but are not limited to one or more slip buttons, one or more teeth, or any combination thereof. The gripping elements 140 extend from the outer surface of the swellable polymeric material of the sealing element 130. The gripping elements 140 can extend from the sealing element 130 at an angle (as shown in FIG. 2B), or alternative, the gripping elements 140 can extend perpendicular from the sealing element 130 (not shown). The gripping elements 140 are configured to make contact with and grip the inner surface of the casing. Each gripping element 140 can have an upper gripping surface that makes contact to the casing. Once in contact, the gripping elements 140 produce enough friction against the inner surface of the casing to hold the valve system 100 into place within the casing.

[0016] The gripping elements 140 generally contain a material durable enough to withstand the pressures and temperatures experienced downhole in the casing. The gripping elements 140 can contain, but are not limited to, one or more materials that include metal (e.g., cast iron, steel, aluminum, magnesium, or alloys thereof), metal carbide (e.g., tungsten carbide), ceramic, thermoplastic (e.g., phenolic resins or plastic), or any combinations thereof. In another embodiment, the gripping elements 140 contain a dissolvable material that can be readily dissolved or deteriorated when exposed to an aqueous fluid, such as a cement or a water-based mud, that is an acidic or alkaline. Exemplary dissolvable materials can be or include, but are not limited to, one or more of aluminum, magnesium, aluminum-magnesium alloy, iron, alloys thereof, degradable polymer, or any combination thereof.

[0017] The sealing element 130 can be directly formed on the mandrel 110 by applying one or more swellable materials thereon. In other examples, the sealing element 130 can be manufactured separately from the mandrel 110 and later placed on the mandrel 110, such as a slip-on swellable sealing element. The sealing element 130 is swellable and contains a swellable material that can be or include, but is not limited to, one or more of polymers, oligomers, rubbers, elastomers, or any combination thereof. For example, the swellable polymeric material can be or include a swellable elastomer.

[0018] As used herein, the terms “swell” or “swellable” means an increase in volume through molecular incorporation of one or more fluids within a component or material of the sealing element. For example, terms used to describe the component or material of the sealing element can be or include, but is not limited to, “swellable sealing element,” “swellable material,” “swellable polymeric material,” “swellable polymer,” and “swellable elastomer.”

[0019] The swellable sealing element or swellable polymeric material can remain dormant until activated by or contacted with one or more fluids or other activation agents. The swelling of the components or materials to be expanded may occur through contact with the activation agent, such as one or more aqueous fluids (e.g., water, brine, or solutions or mixtures containing water), one or more organic fluids (e.g., oil, solvents, or hydrocarbons), or any combination thereof (e.g., aqueous-organic fluid mixtures, emulsions, or inverse emulsions). In some examples, the swellable polymeric material is expandable upon contact with an aqueous fluid. In other examples, the swellable polymeric material is expandable upon contact with an organic fluid. In further examples, the swellable polymeric material is a hybrid swelling material and is expandable upon contact with an aqueous-organic fluid mixture. Once activated and at least partially expanded, the sealing element 130 forms a gas-tight seal when in sealing engagement with the inner surface of the casing.

[0020] In one or more embodiments, the swellable polymeric material can be or contain one or more rubbers. For example, the swellable polymeric material can be or include, but is not limited to, ethylene propylene diene monomer (EPDM) rubber, ethylene propylene monomer rubber, ethylene-propylene-copolymer rubber, ethylene propyl ene-diene terpolymer rubber, ethylene vinyl acetate rubber, polynorbornene rubber, styrene butadiene rubber (SBR), hydrogenized acrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chloroprene rubber, chlorinated polyethylene (CPE) rubber, silicone rubber, natural rubber, crosslinks thereof, or any combination thereof. The swellable polymeric material can also be or include, but is not limited to, methyl methacrylate, polyvinyl chloride (PVC), ethylacetate, acrylonitrile, or any combination thereof. The swellable polymeric material can also include one or more additives, one or more solvents, or other materials to adjust the swellability of the swellable polymeric material.

[0021] In one or more embodiments, a method for installing a valve system (e.g., valve system 100 or other valve systems) into a casing or a pipe used in a downhole environment is provided. The method can include inserting or positioning the valve system into the casing and affixing or connecting the valve system to an inner surface of the casing by exposing the swellable polymeric material to a fluid and expanding the swellable polymeric material into engagement with the inside of the casing, thereby preventing fluid flow through the casing outside of the valve system. The valve system includes a mandrel, a check valve assembly coupled to the mandrel, and a sealing element located on an outer surface of the mandrel. The sealing element contains one or more swellable polymeric materials and a plurality of gripping elements. The valve system can be affixed, set, coupled, connected, or otherwise attached to the inner surface of the casing when the casing is above ground, prior to placing the casing into a downhole environment. The method can also include placing or positioning the casing containing the affixed, connected, or otherwise attached valve system into a borehole, a wellbore, a well, a subterranean formation, or other downhole environment. Once inside the wellbore or other downhole environment, the valve system prevents fluids (e.g., wellbore fluid, drilling fluid, or fracturing fluid) from entering the casing.

[0022] During oil and gas production, the process of cementing a casing into the wellbore of an oil or gas well includes several steps. A string of casings is run in the wellbore to the desired depth. Then, a cement slurry is pumped from outside of the wellbore (e.g., ground surface) and into the casing to fill an annulus between the casing and the wellbore wall to a desired height. A displacement medium, such as a drilling or circulation fluid, is pumped behind the cement slurry in order to push the cement slurry to exit the inside of the casing and enter the annulus. The cement slurry is typically separated from the circulation fluid by at least one cementing plug. Due to the difference in specific gravity between the circulating fluid and the cement slurry, the heavier cement slurry initially drops inside the casing without being pumped by hydrostatic pressure. After the height of cement slurry column outside the casing in the annulus equals the height of the cement slurry column inside the casing, hydrostatic pressure must be exerted on the displacement fluid to force the rest of cement slurry out of the casing and into the annulus. After the desired amount of cement slurry has been pumped into the annulus, it is desirable to prevent the backflow of cement slurry into the casing until the cement slurry sets and hardens. This backflow is produced by the difference in specific gravity of the heavier cement and the lighter displacement fluid.

[0023] In one or more embodiments, a method of preventing the backflow of cement slurry involves placing a check valve, as discussed and described herein, in the lower end of the casing string to prevent the backflow of the cement slurry and/or other fluids into the casing. The check valve is generally located on a conventional casing string near or at the bottom of the casing string. Then, the cement slurry is pumped through the check valve and into the borehole. As the casing is cemented into place in the downhole or subterranean environment, the check valve prevents fluid flow into the casing from the well or formation. Since the check valve maintains the cement and/or fluid from entering the casing, the casing has more buoyancy and does not need to be supported as much as if the end of the casing was open to backflow. Cement is then pumped down the inside of the casing, out of the check valve, and back up the annulus between the casing and the wellbore wall where the cement is allowed to cure.

[0024] In addition to the embodiments described above, embodiments of the present disclosure further relate to one or more of the following paragraphs:

[0025] 1. A valve system insertable into a casing used in a downhole environment, comprising: a mandrel comprising a passageway therethrough; a check valve assembly coupled to the mandrel and operable to provide a fluid flow only in a primary direction through the passageway; and a sealing element located on an outer surface of the mandrel and comprising a swellable polymeric material expandable into sealing engagement with an inner surface of the casing.

[0026] 2. The valve system of paragraph 1, wherein an outer surface of the sealing element comprises gripping elements for gripping the inner surface of the casing.

[0027] 3. The valve system of paragraph 2, wherein the gripping elements are located on the swellable polymeric material.

[0028] 4. The valve system according to any one of paragraphs 1-3, wherein the gripping elements comprise slip buttons, teeth, or a combination thereof.

[0029] 5. A valve system insertable into a casing used in a downhole environment, comprising: a mandrel comprising a passageway therethrough; a check valve assembly coupled to the mandrel and operable to provide a fluid flow only in a primary direction through the passageway; a sealing element located on an outer surface of the mandrel, wherein the sealing element comprises: a swellable polymeric material circumscribing around at least a portion of the mandrel; and slip buttons located on the swellable polymeric material.

[0030] 6. The valve system of paragraph 5, wherein the swellable polymeric material is expandable into sealing engagement with an inner surface of the casing upon contact with an aqueous fluid, an organic fluid, or a combination thereof.

[0031] 7. A method for installing a valve system into a casing used in a downhole environment, comprising: inserting the valve system into the casing, wherein the valve system comprises: a mandrel comprising a passageway therethrough; a check valve assembly coupled to the mandrel and operable to provide a fluid flow only in a primary direction through the passageway; and a sealing element located on an outer surface of the mandrel and comprising a swellable polymeric material; and connecting the valve system to an inner surface of the casing by exposing the swellable polymeric material to a fluid and expanding the swellable polymeric material into sealing engagement with the inner surface of the casing; and placing the casing and the valve system into a wellbore within the downhole environment.

[0032] 8. The method of paragraph 7, wherein connecting the valve system to the inner surface of the casing is conducted above ground prior to placing the casing into the downhole environment.

[0033] 9. The method according to paragraph 7 or 8, wherein the valve system prevents wellbore fluid from entering the casing when in the wellbore.

[0034] 10. The method according to any one of paragraphs 7-9, further comprising cementing the casing in the wellbore by injecting cement from the ground surface through the inside of the casing, out the valve system, and back up the wellbore outside of the casing.

[0035] 11. The method according to any one of paragraphs 7-10, wherein an outer surface of the sealing element comprises gripping elements for gripping the inner surface of the casing.

[0036] 12. The method of paragraph 11, wherein the gripping elements comprise slip buttons, teeth, or a combination thereof.

[0037] 13. The method of paragraph 12, wherein the gripping elements comprise a material selected from the group consisting of ceramic, metal, metal carbide, thermoplastic, and combinations thereof.

[0038] 14. The method according to any one of paragraphs 7-13, wherein the swellable polymeric material is expanded by contacting the swellable polymeric material with the fluid.

[0039] 15. The valve system or the method according to any one of paragraphs 1-14, wherein the gripping elements comprise a material selected from the group consisting of ceramic, metal, metal carbide, thermoplastic, and combinations thereof.

[0040] 16. The valve system or the method according to any one of paragraphs 1-15, wherein the swellable polymeric material is expandable upon contact with an aqueous fluid.

[0041] 17. The valve system or the method according to any one of paragraphs 1-16, wherein the swellable polymeric material is expandable upon contact with an organic fluid.

[0042] 18. The valve system or the method according to any one of paragraphs 1-17, wherein the swellable polymeric material comprises a swellable elastomer.

[0043] 19. The valve system or the method according to any one of paragraphs 1-18, wherein the swellable polymeric material comprises a rubber selected from the group consisting of ethylene propylene diene monomer (EPDM) rubber, ethylene propylene monomer rubber, ethylene-propylene-copolymer rubber, ethylene propylene-diene terpolymer rubber, ethylene vinyl acetate rubber, polynorbornene rubber, styrene butadiene rubber (SBR), hydrogenized acrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chloroprene rubber, chlorinated polyethylene (CPE) rubber, silicone rubber, natural rubber, crosslinks thereof, and any combination thereof.

[0044] 20. The valve system or the method according to any one of paragraphs 1-19, wherein the swellable polymeric material comprises a compound selected from the group consisting of methyl methacrylate, polyvinyl chloride (PVC), ethylacetate, acrylonitrile, and any combination thereof.

[0045] 21. The valve system or the method according to any one of paragraphs 1-20, wherein the swellable polymeric material circumscribes around at least a portion of the mandrel.

[0046] One or more specific embodiments of the present disclosure have been described. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0047] In the following discussion and in the claims, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “including,” “comprising,” and “having” and variations thereof are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, any use of any form of the terms “connect,” “engage,” “couple,” “attach,” “mate,” “mount,” or any other term describing an interaction between elements is intended to mean either an indirect or a direct interaction between the elements described. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” “upper,” “lower,” “up,” “down,” “vertical,” “horizontal,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.

[0048] Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function.

[0049] Reference throughout this specification to “one embodiment,” “an embodiment,” “an embodiment,” “embodiments,” “some embodiments,” “certain embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, these phrases or similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0050] Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and/or the combination of any two upper values are contemplated unless otherwise indicated. Certain lower limits, upper limits and ranges appear in one or more claims below. All numerical values are “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

[0051] The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.