Gate valves with grease retention skirts
Patent Information
- Application Number
- PCT/US2026/017123
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-27
- Filing Date
- 2026-02-27
- Publication Date
- 2026-09-03
Smart Images
Figure US2026017123_03092026_PF_FP_ABST
Abstract
Description
IS25.0263-WO-PCTGATE VALVES WITH GREASE RETENTION SKIRTSCROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to and benefit of U.S. Provisional Patent Application No. 63 / 764,205 filed February 27, 2025, which is hereby incorporated by reference herein in its entirety for all purposes.BACKGROUND
[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
[0003] In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth.Particularly, once a desired subterranean resource is discovered, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that control drilling or extraction operations.
[0004] Additionally, such wellhead assemblies may use a fracturing tree and other components to facilitate a fracturing process and enhance production from a well. As will be appreciated, resources such as oil and natural gas are generally extracted from fissures or other cavities formed in various subterranean rock formations or strata. To facilitate extraction of such resources, a well may beIS25.0263-WO-PCTsubjected to a fracturing process that creates one or more man-made fractures in a rock formation. This facilitates, for example, coupling of pre-existing fissures and cavities, allowing oil, gas, or the like to flow into the wellbore. Such fracturing processes typically include injecting a fracturing fluid — which is often a mixture including proppant (e.g., sand) and water — into the well to increase the well’s pressure and form the man-made fractures. The high pressure of the fluid increases crack size and crack propagation through the rock formation to release oil and gas, while the proppant prevents the cracks from closing once the fluid is depressurized. During fracturing operations, fracturing fluid may be routed via fracturing lines (e.g., pipes) to fracturing trees or other assemblies installed at wellheads.Conventional fracturing trees have valves that can be opened and closed to control flow of fluid through the fracturing trees into the wells.SUMMARY
[0005] Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
[0006] Embodiments of the present disclosure generally relate to valves for controlling fluid flow. More specifically, some embodiments relate to frac valves for controlling the flow of fracturing fluid in fracturing systems. The frac valves may be provided in a wellhead assembly (e.g., in a fracturing tree) or a fluid supply system (e.g., a fracturing manifold) to control the flow of fracturing fluid during fracturing operations at a wellsite, for example. In some embodiments, a frac valve includes a gate positioned in a cavity of a gate valve housing. The gate includes an aperture and can be moved within the cavity between open and closed positions to control flow through a bore of the gate valve. One or more grease skirts may be positioned in the cavity along the gate to inhibit grease loss from the cavity through the aperture during valve operation. Further, in at least some embodiments, the grease skirts are spring-biased to maintain contact of the grease skirts against the gate.IS25.0263-WO-PCT
[0007] Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0009] FIG. 1 generally depicts a fracturing system having valves for controlling flow in accordance with an embodiment of the present disclosure;
[0010] FIG. 2 is a perspective view of a valve having grease skirts in a valve cavity in accordance with one embodiment;
[0011] FIG. 3 is a cross-section of the valve of FIG. 2 and shows a gate of the valve in an open position in accordance with one embodiment;
[0012] FIG. 4 is a cross-section of the valve of FIG. 2 showing the gate in a closed position in accordance with one embodiment;
[0013] FIGS. 5 and 6 are additional section views of the valve of FIG. 2 in accordance with one embodiment;IS25.0263-WO-PCT
[0014] FIG. 7 is a detail view of the valve, grease skirts, and seats of FIG. 2 and shows biasing assemblies installed in rear surfaces of the grease skirts in accordance with one embodiment;
[0015] FIG. 8 depicts front surfaces of a seat and a grease skirt of FIG. 7 in the valve cavity in accordance with one embodiment;
[0016] FIG. 9 is a perspective view of a grease skirt and a biasing assembly of FIG. 7 in accordance with one embodiment;
[0017] FIG. 10 is an exploded view of the grease skirt and the biasing assembly of FIG. 7 in accordance with one embodiment;
[0018] FIG. 11 is a detail view showing a portion of the biasing assembly of FIG. 7 having springs positioned between the grease skirt and a backing plate in accordance with one embodiment;
[0019] FIG. 12 is a detail view showing a seat, a seat holder, and a portion of a grease skirt in a valve cavity in accordance with one embodiment;
[0020] FIG. 13 is a perspective view of the seat of FIG. 12 in accordance with one embodiment;
[0021] FIG. 14 is a detail view showing the seat of FIG. 12 having a tapered lead surface in accordance with one embodiment;
[0022] FIG. 15 is a detail view showing the seat of FIG. 12 having a different tapered lead surface in accordance with one embodiment;
[0023] FIG. 16 is a perspective view of the seat, seat holder, and grease skirt of FIG. 6 in accordance with one embodiment;
[0024] FIG. 17 is a perspective view of a gate valve having grease skirts in a valve cavity in accordance with one embodiment;IS25.0263-WO-PCT
[0025] FIG. 18 is a perspective view of the gate valve of FIG. 17 with the bonnets and actuator omitted to show internal components of the valve in accordance with one embodiment;
[0026] FIG. 19 is a perspective view of internal components of the valve of FIG. 17 in accordance with one embodiment;
[0027] FIG. 20 is an exploded view of the internal components of FIG. 19 in accordance with one embodiment;
[0028] FIG. 21 is a cross-section of the valve of FIG. 18 in accordance with one embodiment;
[0029] FIG. 22 is a front perspective view of a grease skirt of FIG. 21 in accordance with one embodiment;
[0030] FIG. 23 is an exploded view of a grease skirt and biasing assembly of FIG. 21 in accordance with one embodiment;
[0031] FIG. 24 is a section view showing a grease skirt and a seat in a gate valve cavity in accordance with one embodiment;
[0032] FIG. 25 depicts the grease skirt of FIG. 24 in accordance with one embodiment;
[0033] FIG. 26 is a detail plan view showing the grease skirt of FIG. 24 in the gate valve cavity in accordance with one embodiment;
[0034] FIG. 27 is another section view of the grease skirt and seat of FIG. 24 in accordance with one embodiment;
[0035] FIG. 28 is an elevational view of the seat of FIG. 24 surrounded by the grease skirt in the valve cavity in accordance with one embodiment;IS25.0263-WO-PCT
[0036] FIG. 29 is a section view showing a grease skirt with an aperture in a gate valve cavity in accordance with one embodiment;
[0037] FIG. 30 is a section view showing another grease skirt with an aperture in a gate valve cavity in accordance with one embodiment;
[0038] FIG. 31 is a perspective view of the grease skirt of FIG. 29 in accordance with one embodiment;
[0039] FIG. 32 is a perspective view of the grease skirt of FIG. 30 in accordance with one embodiment;
[0040] FIG. 33 is an exploded view of the grease skirt of FIG. 30 in accordance with one embodiment; and
[0041] FIG. 34 is a detail section view showing a neck of one of the grease skirts of FIGS. 29 or 30 in the gate valve cavity in accordance with one embodiment.DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0042] Specific embodiments of the present disclosure are described below. 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.IS25.0263-WO-PCT
[0043] When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components.
[0044] Conventional frac valves often depend on a greasing process to maintain their operating integrity. This greasing process typically requires large quantities of grease to fill a grease cavity of a conventional frac valve, and its purpose is to provide lubrication to the gate-to-seat operation, to seal the valve, and to prevent other media such as sand from entering the cavity, which may cause the valve to leak or malfunction. Due to the operating conditions of frac valves, applied grease may get washed out of the cavity of a conventional frac valve. This can occur during the open / closing cycle of the frac valve when the cavity is exposed to the main bore, for example. In at least some embodiments of the present technique, however, a frac valve includes grease skirts that are biased against a gate to maintain a close fit to the gate throughout valve cycling and reduce grease loss from the valve. The grease skirts may be retrofitted to an existing valve without reworking the body of the valve in at least some cases.
[0045] Turning now to the present figures, an example of a fracturing system 10 is provided in FIG. 1 in accordance with certain embodiments. The fracturing system 10 facilitates extraction of natural resources, such as oil or natural gas, from a subterranean formation via a well 12 and a wellhead 14. Particularly, by injecting a fracturing fluid into the well 12, the fracturing system 10 increases the number or size of fractures in a rock formation or strata to enhance recovery of natural resources present in the formation. Well 12 is a surface well in some embodiments, but it will be appreciated that resources may be extracted from other wells 12, such as platform or subsea wells.IS25.0263-WO-PCT
[0046] The fracturing system 10 includes various components to control flow of a fracturing fluid into the well 12. For instance, the fracturing system 10 depicted in FIG. 1 includes a wellhead assembly 16 that receives fracturing fluid from a fluid supply system 22. In some embodiments, the wellhead assembly 16 includes one or more frac valves 18 to control flow of fracturing fluid into the well 12. More particularly, the wellhead assembly 16 can include a fracturing tree 20 having one or more frac valves 18. Various examples of frac valves are described below in accordance with the present techniques. In some embodiments, a fracturing tree 20 may include one or more of these frac valves to control flow of fracturing fluid through the tree 20 into the well 12 (or from the well 12 in some instances, such as during a flowback operation). Any of the described frac valves could be used as an upper master valve or a lower master valve of the fracturing tree 20, for instance. The sizes and pressure ratings of the frac valves 18 may vary depending on the intended application. In some instances, the frac valves 18 are constructed for high-pressure applications, such as up to 10000 psi, 12000 psi, or 15000 psi (approximately 70000 kPa, 80000 kPa, or 100000 kPa). The frac valves 18 may have large bores, such as a nominal bore diameter of five and one-eighth inches (approximately 13 cm) or seven and one-sixteenth inches (approximately 18 cm) in some embodiments. Those skilled in the art will appreciate that the fracturing tree 20 could include other elements, such as connection blocks, wing valves, a swab valve, and a frac head. In other embodiments, the wellhead assembly 16 may include one or more frac valves 18 without a fracturing tree mounted over the wellhead 14.
[0047] The fracturing fluid supply system 22 may also (or instead) include one or more frac valves 18 for controlling flow of fracturing fluid to the well 12. The frac valves 18 of the fracturing fluid supply system 22 may be provided in the form of a frac valve described below or in any other suitable form. In some embodiments, the fracturing fluid supply system 22 includes trucks that pump the fracturing fluid to the wellhead assembly 16, but any suitable sources of fracturing fluid and manners for transmitting such fluid to the wellhead assembly 16 may be used. In some instances, the fracturing fluid supply system 22 includes a fracturing manifold for distributing fracturing fluid to multiple wells 12 via respective wellheadIS25.0263-WO-PCTassemblies 16. The fracturing manifold may include frac valves 18 to control flow of fracturing fluid to the individual wells 12.
[0048] In some embodiments, a frac valve 18 of the fracturing system 10 is embodied by one of the valves 30 described below. Various examples of valves 30 are described below as frac valves 30 for controlling flow of fracturing fluids. But the various valves 30 described herein could also or instead be used in other applications to convey and control flow of other fluids.
[0049] An example of a frac valve 30 is depicted in FIGS. 2-6 in accordance with one embodiment. More specifically, FIG. 2 is a perspective view of the frac valve 30, and FIGS. 3-6 are section views of the valve 30. The frac valve 30 includes a housing having a main body 32 and may be fastened between other components to selectively control flow of pressurized fluid between the other components through the valve 30. The depicted main body 32 includes connection flanges 34 to facilitate connection to the other components, but other manners of connecting the frac valve 30 to such other components may be used.
[0050] The main body 32 includes a bore 36, for conveying fracturing fluid (or other fluid) through the frac valve 30, and a cavity 38 transverse to the bore 36. The valve 30 includes an internal gate 42 having an aperture 44 that may be selectively aligned with the bore 36 to control flow through the frac valve 30. Flow through the frac valve 30 may be controlled by moving the gate 42 within the cavity 38 (transverse to the bore 36) between an open position (FIG. 3) that allows flow through the bore 36 via the aperture 44 and a closed position (FIG. 4) in which the body of the gate 42 blocks flow through the bore 36. The gate 42 has been omitted from some figures, such as FIGS. 2, 5, and 6, to better show other valve components.
[0051] It will be appreciated that the valve housing may include bonnets fastened to the upper and lower surfaces of the main body 32 to enclose the gate 42 within the cavity 38. The bonnets may be fastened to the main body 32 with studded connections or in any other suitable manner. Further, it will be understood that theIS25.0263-WO-PCTvalve 30 may include an actuator for moving the gate 42 between the open and closed positions and controlling flow through the valve 30. For instance, the actuator may include a hydraulic actuator, a manual actuator, an electric actuator, a pneumatic actuator, or combinations of such actuators.
[0052] As shown in FIGS. 3-6, the valve 30 includes annular seats 46 positioned to seal against opposite sides of the gate 42. In at least some embodiments, the seats 46 are installed in the valve 30 along with annular seat holders 48. The seats 46 may be telescoping seats that move relative to the seat holders 48 in operation, such as in response to pressure of fluid from the bore 36 or the cavity 38. The seats 46 provide metal-to-metal sealing against the gate 42 in at least some embodiments. The seats 46 may also or instead carry a polymer seal (e.g., an elastomer or plastic seal ring) that seals against the gate 42 in some instances.
[0053] The cavity 38 may be filled with a lubricant (e.g., grease), which may facilitate operation of the valve 30 and inhibit ingress of particulates (e.g., proppant from fracturing fluid in the bore 36) into the cavity 38. The valve 30 of FIGS. 2-6 also includes grease skirts 54 installed in the cavity 38. These grease skirts 54 facilitate retention of grease (or other lubricant) within the cavity 38 and, as such, may also be referred to as grease retention skirts or grease retainers.
[0054] As shown in FIGS. 3 and 4, a pair of grease skirts 54 are installed in an upper end of the cavity 38 on opposite sides of the gate 42. The grease skirts 54 may protrude from the main body 32, such as presently shown, or may be positioned fully within the main body 32. In at least some instances, the grease skirts 54 include slots 56 to facilitate installation or removal of the grease skirts 54 from the cavity 38.
[0055] Biasing assemblies may also be installed in the cavity 38 to push the grease skirts 54 against the gate 42. In the embodiment depicted in FIGS. 2-6, for example, biasing assemblies with backing plates 58 are installed behind the grease skirts 54 to bias the grease skirts 54 toward the gate 42. Additional details of these grease skirts 54 and biasing assemblies may be better understood with reference toIS25.0263-WO-PCTthe detail view of FIG. 7, in which the gate 42 has been omitted for clarity. Each of the grease skirts 54 of FIG. 7 is installed with a biasing assembly, including a backing plate 58 and springs 60, positioned in a recess 62 in a rear surface of the grease skirt 54. When installed in the cavity 38, the springs 60 are compressed between the grease skirt 54 and the backing plate 58. The compressed springs 60 bias the grease skirt 54 toward the gate 42 and bias the backing plate 58 away from the gate 42 (and toward a sidewall of the cavity 38). This causes a front surface or face 64 of the grease skirt 54 to press against the gate 42, while the backing plate 58 presses against the main body 32 (specifically, a sidewall of the cavity 38). In some embodiments, including the embodiment depicted in FIGS. 2-8, the grease skirts 54 and their associated seats 46 are formed as separate bodies and are arranged such that the biasing assemblies (e.g., backing plates 58 and springs 60) of the grease skirts 54 do not bias the seats 46 toward the gate 42 of the valve 30.
[0056] As the gate 42 is moved to close the valve 30, the aperture 44 moves from the open position in which the aperture 44 is aligned with the bore 36 through the main body 32 (e.g., as in FIG. 3) to the closed position in which the aperture 44 is isolated from the bore 36 (e.g., as in FIG. 4). This movement of the aperture 44 is generally represented by the dashed lines 68 in FIG. 8, with the dashed circle representing a position of the aperture 44 along the grease skirt 54 when the gate 42 is in a closed position and the aperture 44 is isolated from the bore 36. When the valve 30 is closed, the grease skirts 54 substantially cover (i.e., cover at least ninety percent of) the aperture 44 of the gate 42. In at least some instances, this may include covering at least ninety-five percent of the aperture 44 or fully covering the aperture 44. As the gate 42 strokes from the open position to the closed position, the aperture 44 is drawn out of alignment with the seats 46 along the bore 36. The grease skirts 54 overlap the aperture 44 as it moves between the open and closed positions and inhibit loss of grease from the cavity 38 into the bore 36 via the aperture 44. Moreover, the biasing assemblies can provide a preload to the grease skirts 54 that maintains contact between the front faces 64 of the grease skirts 54 and the gate 42, which may further limit grease loss from the cavity 38 through the aperture 44 during valve operation. Although specific examples of the biasingIS25.0263-WO-PCTassemblies are described herein, the bias may be applied to the grease skirts 54 in other manners, such as with other mechanical devices or with gas pressure.
[0057] The grease skirts 54 may include grease channels 66 to facilitate lubrication of the gate-to-seat motion of gate 42 and seats 46. In FIGS. 6 and 8, for instance, the grease skirts 54 include grease channels 66 in the front faces 64 that contact the gate 42. These grease channels 66 allow grease in the cavity 38 to propagate down the front faces 64 and be applied to the abutting gate 42. In FIG. 8, for instance, the front face 64 of the grease skirt 54 includes three grease channels 66 extending downward along the face 64 from an upper end of the grease skirt 54 — two longer grease channels 66 on opposite sides of the face 64 and a shorter central grease channel 66. As shown in FIG. 8, the grease channels 66 do not overlap the aperture 44 (whose movement is generally represented by the dashed lines 68) during operation. Although three parallel grease channels 66 are shown in FIG. 8, the grease skirt 54 could have any suitable number and arrangement of grease channels 66. In some instances, the grease channels 66 are omitted.
[0058] As discussed above, biasing assemblies may be used to bias the grease skirts 54 against the gate 42. One example of such a biasing assembly received in a grease skirt 54 is shown in FIGS. 9-11 in accordance with one embodiment. When installed in the grease skirt 54, such as shown in FIGS. 9 and 11, the biasing assembly protrudes from a recess 62 in the rear surface of the grease skirt 54. The depicted biasing assembly includes the backing plate 58, the springs 60, and fasteners 72, which attach the backing plate 58 to the grease skirt 54. The springs 60 may be provided in any suitable number and form. In some instances, the springs 60 are disc springs (e.g., Belleville springs), wave springs, coiled springs, leaf springs, or elastomer springs.
[0059] The fasteners 72 are received in apertures 74 of the backing plate 58 and holes 76 of the grease skirt 54. The fasteners 72 may also be provided in any suitable number and form but are depicted in FIGS. 9-11 as having enlarged heads received in the apertures 74 to retain the backing plate 58 and threaded ends for engagement with threaded holes 76 of the grease skirt 54. The backing plate 58 can move withIS25.0263-WO-PCTrespect to the grease skirt 54 along the fasteners 72. As noted above, when the grease skirt 54 is positioned in the valve 30 between the gate 42 and the sidewall of the cavity 38, the springs 60 are compressed and bias the grease skirt 54 against the gate 42 and bias the backing plate 58 against the sidewall of the cavity 38.
[0060] As shown in FIGS. 9 and 10, the grease skirt 54 includes an arcuate surface 78 for partially surrounding the annular seat 46 when installed in the valve 30. The arcuate surface 78 may conform to a portion of the circumferential outer curved surface of the annular seat 46 to limit space between the grease skirt 54 and the annular seat 46 when these components are installed in the valve housing. This may reduce fluid communication between the cavity 38 and the aperture 44 of the gate 42, such as when the gate 42 is moved to or from the closed position, and reduce loss of grease from the cavity 38 during valve operation.
[0061] A detail section view of the grease skirt 54 positioned next to a seat 46 and seat holder 48 within the main body 32 is provided in FIG. 12, and a perspective view of the seat 46 is provided in FIG. 13. As shown, the seat 46 includes annular grooves 84, 88, and 90 and the seat holder 48 includes annular grooves 86.Polymeric rings may be positioned in the grooves 84, 86, 88, and 90, such as for sealing, scraping, or other purposes. Such polymeric rings may include any suitable material, examples of which may include elastomer, thermoplastic, or fluoropolymer rings, among others. In at least one embodiment, the rings installed in the grooves 84 are polytetrafluoroethylene (PTFE) rings, the rings installed in the grooves 86 are PTFE or polyetheretherketone (PEEK) rings, and the ring installed in the groove 88 is an elastomer ring. Further, a ring 92 of any suitable material (e.g., a polymer) may be installed in the groove 90 to abut the arcuate surface 78 of the grease skirt 54 and limit ingress of proppants or other particulates into the cavity 38 through the gap between the grease skirt 54 and the seat 46. The number and location of grooves in the seat 46 and seat holder 48 vary in different embodiments. One of the grooves 84 in the front face of the seat 46 (e.g., the outer groove 84) or both grooves 84 may be omitted in some embodiments, for example. Additional grooves, such as an annular groove 96 on the outer surface of the seat holder 48 and an annular groove 98 spanning the inner surfaces of the seat 46 and seat holder 48,IS25.0263-WO-PCTmay also receive rings (e.g., sealing rings, scraping rings, or trash rings), be left empty, or be omitted.
[0062] In FIG. 12, the grease skirt 54 is shown with a lip 80 provided along the arcuate surface 78 (e.g., along the entire arc of the surface 78). This lip 80 overlaps and partially covers a tapered lead surface 94 of the seat 46 such that a distal end of the lip 80 is positioned between the seat 46 and the gate 42. In other instances, the lip 80 may be omitted from the grease skirt 54. The angle of the tapered lead surface 94 with respect to the front sealing face of the seat 46 may vary between embodiments. Two examples of seats 46 with differently angled tapered lead surfaces 94 are depicted in FIGS. 14 and 15, with the seat 46 of FIG. 14 having a deeper lead angle than that of FIG. 15. With or without a lip 80, the curved end of the grease skirt 54 (along arcuate surface 78) may receive the seat 46, such as shown in FIG. 16, when the grease skirt 54 is installed in the main body 32 of the valve 30.
[0063] Another example of a frac valve 30 is depicted in FIGS. 17-23. Like that of FIGS. 2-6, the frac valve 30 depicted in FIG. 17 and 18 includes a main body 32, flanges 34, a bore 36, and a cavity 38. Bonnets 102 are shown fastened to the upper and lower ends of the main body 32 to enclose the cavity 38. An actuator 104 may be used to open and close the valve 30 by moving a gate 42 in the cavity 38, such as described above. Although depicted as a manual actuator 104 (i.e., a handwheel) in FIG. 17, any suitable actuator may be used with the valve 30.
[0064] Certain internal components of this valve 30 are depicted in FIGS. 19 and 20, while FIG. 21 is a cross-section of the valve 30 showing these internal components installed within the cavity 38. As shown in FIGS. 19 and 20, the valve 30 includes a gate 42 positioned between annular seats 46 and having an aperture 44 that may be selectively aligned with the seats 46 and the bore 36 to control flow of fracturing fluid through the valve 30. Grease skirts 54 may be positioned about portions of the seats 46 and may include biasing assemblies with backing plates 58 for biasing the grease skirts 54 against the gate 42 to limit grease loss through the aperture 44 during valve cycling, such as described above. An actuation rod 106 is coupled to the gate 42 and can move the gate 42 between theIS25.0263-WO-PCTopen and closed positions. An additional rod 108 (e.g., a balancing rod) may also be coupled to the gate 42. The assembly depicted in FIGS. 19 and 20 also includes inserts 112 that may be installed above the grease skirts 54 (e.g., in a bonnet 102) and additional grease skirts 114 that may be positioned about portions of the seats 46 within the cavity 38. In FIG. 21, the grease skirts 54 are shown above the seats 46 while the grease skirts 114 are shown below the seats 46.
[0065] A grease skirt 54 of FIGS. 19-21 is depicted in more detail in FIGS. 22 and 23. Each of the grease skirts 54 includes an arcuate surface 78 for receiving a seat 46 and a front face 64 with grease channels 66, such as described above. The biasing assembly includes a backing plate 58 movably coupled to the grease skirt 54 and springs 60 that bias the backing plate 58 toward the sidewall of the cavity 38 and bias the grease skirt 54 toward the gate 42. The springs 60 are shown in FIG. 23 as wave springs but may be provided in any other suitable form. The biasing assembly also includes retaining heads 122 that are received in apertures 74 of the backing plate 58. Fasteners 72 are received through the retaining heads 122 and the apertures 74 and threaded into holes 76 in mounting pillars 118 of the grease skirt 54. In this arrangement, the retaining heads 122 and fasteners 72 couple the backing plate 58 to the grease skirt 54 while allowing the backing plate 58 to move with respect to the grease skirt 54 along the pillars 118.
[0066] In some other embodiments, a valve 30 includes grease skirts 54 that surround the seats 46 in the cavity 38. In FIGS. 24-28, for example, a grease skirt 54 includes an aperture 132 for receiving a seat 46. The grease skirt 54 surrounds the full outer circumference of the seat 46 and, as shown in FIG. 24, fills portions of the cavity 38 above and below the seat 46. While FIG. 24 is a section view showing one side of the valve 30, it will be understood that the other side of the valve 30 may include an additional grease skirt 54 and seat 46 (which are identical to those depicted in FIG. 24 in at least some instances), and that the grease skirts 54 may be biased toward a gate 42 installed between the grease skirts 54 and seats 46 to limit fluid communication between the cavity 38 and an aperture 44 of the gate 42, such as described above.IS25.0263-WO-PCT
[0067] While these grease skirts 54 could include a backing plate 58 and springs 60 positioned between the backing plate 58 and the grease skirt 54 like those described above, the biasing assembly for each of the grease skirts 54 of the valve 30 of FIG. 24 may instead include one or more springs positioned between the grease skirt 54 and a sidewall of the cavity 38 to bias the grease skirt 54 toward the gate 42. As shown in FIG. 25, for example, each grease skirt 54 includes recesses 134 in a rear surface 136 of the grease skirt 54. The recesses 134 receive springs 138, which protrude from the recesses 134. The springs 138 may take any suitable form but are compressible elastomer or other polymer material in some embodiments. More specifically, in FIG. 25 the depicted springs 138 are lengths of elastomer O-ring cord having a square profile. When the grease skirts 54 are installed in the cavity 38, the springs 138 are compressed between the grease skirts 54 and the sidewall of the cavity 38, as generally shown in FIG. 26. This causes the springs 138 to apply a biasing force to the grease skirts 54, which pushes the front faces 64 of the grease skirts 54 against the gate 42 of the valve 30. The grease skirts 54 of FIGS. 24-28 and their associated seats 46 are formed as separate bodies and are arranged such that the biasing assemblies (e.g., springs 138) of the grease skirts 54 do not bias the seats 46 toward the gate 42 of the valve 30. The grease skirts 54 of any of the valves 30 described herein may be made of any suitable material, such as metal or plastic. In some embodiments, the grease skirts 54 are made of Phenolic 6401 or another thermoset molding compound.
[0068] The seats 46 may also be formed of any suitable material but are provided as metal rings in some embodiments and provide metal-to-metal sealing against a metal gate 42. The seats 46 may be installed in the cavity 38 with seat holders 48 in some instances, such as shown in FIG. 27. A barrier ring 142 (e.g., a trash ring) may be provided along the inner surfaces of the seat 46 and seat holder 48 to limit ingress of proppant or other particulates from the bore 36 into the interstitial space between the seat 46 and the seat holder 48. In some instances, opposite edges of the grease skirt 54 near the aperture 132 may bulge outward to accommodate the seat 46, such as shown in FIG. 28.IS25.0263-WO-PCT
[0069] While some examples of grease skirts 54 and associated seats 46 being formed as separate bodies are discussed above, in some embodiments the separate seats 46 are omitted and the sealing operation of the seats 46 is incorporated into the grease skirts 54. In such instances, the grease skirts 54 seal around the aperture 44 of the gate 42 without separate annular seats 46 when the gate is in the open position and may be referred to as seat skirts. Examples of such seat skirts are depicted in FIGS. 29-34. In FIG. 29, the depicted grease skirt 54 extends through the cavity 38 and includes an aperture 144 to allow flow through the bore 36 when the valve 30 is open. The grease skirt 54 in FIG. 30 similarly includes an aperture 144 but is shortened at one end and fills less of the cavity 38. Although the section views of FIGS. 29 and 30 show just one side of the valve 30, the other side of the valve 30 may also include an additional grease skirt 54 (e.g., an identical grease skirt 54) so that the grease skirts 54 abut opposite sides of the gate 42.
[0070] The grease skirts 54 of FIGS. 29 and 30 are depicted in FIGS. 31 and 32, respectively. The grease skirt 54 is depicted in FIG. 31 as including springs 138, such as described above, while springs 138 are omitted from the grease skirt 54 of FIG. 32. Both of these grease skirts 54 include a neck 146 that may be received in a socket of the main body 32 when the grease skirt 54 is installed in the valve 30, such as shown in FIG. 34. These grease skirts 54 may also include a seal 148, a spring 150, and a trash ring 152, such as shown in FIGS. 31-34. The seal 148 (e.g., an elastomer O-ring) seals between the neck 146 and the main body 32. The trash ring 152 inhibits ingress of proppant or other particulates behind the neck 146 from the bore 36. Further, the spring 150 is compressed between the grease skirt 54 and the main body 32 and biases the grease skirt 54 against the gate 42 to facilitate sealing engagement of the front face 64 of the grease skirt 54 with the gate 42.
[0071] While the aspects of the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, andIS25.0263-WO-PCTalternatives falling within the spirit and scope of the invention as defined by the following appended claims.
Claims
IS25.0263-WO-PCTCLAIMS1. A fracturing apparatus comprising:a frac valve to control flow of fracturing fluid through the frac valve, the frac valve comprising:a housing having a bore to convey the fracturing fluid and a cavity that is transverse to the bore;a gate positioned in the cavity, wherein the gate is movable within the cavity between an open position and a closed position and has an aperture that allows the fracturing fluid to flow through the frac valve via the bore and the aperture when the gate is in the open position;a grease skirt positioned in the cavity between the gate and the housing such that the grease skirt substantially covers the aperture of the gate when the gate is in the closed position and inhibits loss of grease from the cavity into the bore via the aperture as the gate moves between the open position and the closed position; anda biasing assembly positioned to bias the grease skirt toward the gate.
2. The fracturing apparatus of claim 1, wherein the grease skirt includes a front surface and a rear surface, the front surface of the grease skirt abuts the gate, the rear surface of the grease skirt includes a recess, and the biasing assembly is positioned in the recess of the rear surface of the grease skirt.
3. The fracturing apparatus of claim 2, wherein the biasing assembly protrudes from the recess of the rear surface of the grease skirt and presses against a sidewall of the cavity.
4. The fracturing apparatus of claim 2, wherein the biasing assembly includes:IS25.0263-WO-PCTa backing plate received in and protruding from the recess of the rear surface of the grease skirt; anda spring positioned between the backing plate and the grease skirt.
5. The fracturing apparatus of claim 4, wherein the spring includes a disc spring.
6. The fracturing apparatus of claim 2, wherein the biasing assembly includes a spring received in and protruding from the recess of the rear surface of the grease skirt.
7. The fracturing apparatus of claim 6, wherein the spring includes an elastomer.
8. The fracturing apparatus of claim 7, wherein the elastomer includes a length of O-ring cord.
9. The fracturing apparatus of claim 1, wherein the frac valve includes an annular seat positioned to seal against the gate around the aperture when the gate is in the open position.
10. The fracturing apparatus of claim 9, wherein the grease skirt and the annular seat are arranged such that the biasing assembly does not bias the annular seat toward the gate.
11. The fracturing apparatus of claim 9, wherein the grease skirt includes a lip that overlaps a tapered lead surface of the annular seat such that a distal end of the lip is positioned between the annular seat and the gate.IS25.0263-WO-PCT12. The fracturing apparatus of claim 9, wherein the grease skirt surrounds the annular seat.
13. The fracturing apparatus of claim 1, wherein the grease skirt is a seat skirt that seals around the aperture of the gate without a separate annular seat when the gate is in the open position.
14. The fracturing apparatus of claim 1, wherein the grease skirt includes a front surface having at least one channel to communicate grease to the gate while the front surface abuts the gate.
15. A fracturing apparatus comprising:a grease skirt configured to be positioned in a cavity of a valve housing, between a gate and the valve housing, such that the grease skirt substantially covers an aperture of the gate when the gate is in a closed position and inhibits loss of grease from the cavity into a bore of the valve housing via the aperture of the gate as the gate moves between an open position and the closed position; anda biasing assembly configured to bias the grease skirt toward the gate.
16. The fracturing apparatus of claim 15, wherein the biasing assembly is installed in a recess of the grease skirt.
17. The fracturing apparatus of claim 15, wherein the biasing assembly includes a spring.
18. A method of operating a frac valve that includes a housing, having a bore and a cavity transverse to the bore, and a gate positioned in the cavity, the method comprising:IS25.0263-WO-PCTbiasing a grease skirt positioned in the cavity between the gate and the housing against the gate;moving the gate from an open position to a closed position while the grease skirt is biased against the gate; andsubstantially covering an aperture of the gate with a front face of the biased grease skirt.
19. The method of claim 18, comprising biasing a backing plate installed in a recess of a rear surface of the grease skirt away from the gate and against a sidewall of the cavity.
20. The method of claim 18, comprising applying grease to the gate from a grease channel running along the front face of the biased grease skirt.