IMPROVED ROBUSTNESS OF OPENING / CLOSING OF THE CHECK VALVE

Abstract

A valve assembly (100) used in subterranean wellbore systems includes a valve member (106) biased toward a closed position by a pair of opposing spring wires (120). The spring wires (120) provide sufficient torque to ensure robust operation of the valve member (106) and allow sufficient fluid flow through the limited space available in the valve assembly (100). Two symmetrical pairs of spring wires (120) can be robustly manufactured and individually installed without unnecessary accumulation of tolerances or manufacturing errors, thereby providing predictable torque levels to the valve member (106).The spring wires (120) may be secured in blind holes or other features defined in a circumferential surface of the valve member (106) to ensure that the springs remain engaged in the valve member (106) throughout operation of the valve assembly (100). Fig.2A.

Description

Title of the invention: IMPROVING THE ROBUSTNESS OF THE OPENING / CLOSING OF THE FLAP VALVE

[0001] CROSS REFERENCE TO AN ASSOCIATED APPLICATION

[0002] This application claims priority from non-provisional U.S. Patent Application No. 17 / 240,326 filed on April 26, 2021.

[0003] CONTEXT

[0004] The present invention relates generally to equipment and operations performed in conjunction with subterranean wellbores. Exemplary embodiments described herein include flapper valve assemblies that are biased toward a closed configuration.

[0005] Subterranean safety valves are often used to control fluid flow in a tubing string or other downhole casing strings. For example, a subterranean safety valve may be maintained in an open configuration during nominal operations and may be moved to a closed configuration to block upward flow of formation fluids through the tubing string in the event of a failure or unsafe condition at the surface. A valve member, or a "poppet," may be pivotably provided to configure the valve in the open and closed configurations. Hydraulic pressure may be applied to pivot the valve member to an open position, and when the hydraulic pressure is removed, either manually or automatically in response to an unsafe condition, a biasing member may operate to pivot the valve member to a closed position.

[0006] Torsion springs and helical extension springs are often provided as the biasing element that urges the valve member toward the closed position. These types of springs may have limited torque capacity due to the limited space available in a subsurface valve assembly. With limited torque capacity, these springs may not fully move the valve member to the closed position, which could potentially allow hazardous fluids to escape into the surrounding environment through the partially closed production string. Brief description of the drawings

[0007] The invention is described in detail below, by way of example only, on the basis of examples shown in the attached figures, among which:

[0008] [Fig. 1] is a partial cross-sectional side view of a wellbore system including a valve assembly according to aspects of the present invention;

[0009] [Fig.2A] is a perspective view of a valve assembly, which may be used in the wellbore system of [Fig.l], illustrating a valve member biased toward a closed position with a spring wire extending through a saddle defined in the valve member;

[0010] [Fig.2B] is a perspective view of the spring wire of [Fig.2A];

[0011] [Fig.3] is a perspective view of another embodiment of a spring wire including resistance bands thereon, which may be used in the valve assembly of [Fig.2A] engaged in the saddle of the valve member, according to aspects of the present invention;

[0012] [Fig.4] is a perspective view of another embodiment of a valve member including a plurality of saddle grooves defined therein, which may be used in the valve assembly of [Fig.2A] in engagement with a spring wire, in accordance with aspects of the present invention;

[0013] [Fig.5A] is a perspective view of a valve assembly according to aspects of the present invention, which may be used in the wellbore system of [Fig.1], illustrating a valve member biased toward a closed position with a pair of opposing spring wires engaged in a pair of blind holes defined in the valve member;

[0014] [Fig.5B] is a perspective view of the pair of spring wires of [Fig.5A], according to aspects of the present invention;

[0015] [Fig.6] is a perspective view of another embodiment of a valve member that may be used in the valve assembly of [Fig.5A], illustrating a pair of blind holes for receiving spring wire ends, in accordance with aspects of the present invention;

[0016] [Fig.7A] and [Fig.7B] are perspective and side views of another embodiment of a valve member including a channel defined therein for receiving free ends of spring wires, according to aspects of the present invention;

[0017] [Fig.8A] and [Fig.8B] are perspective and end views of another embodiment of a valve assembly according to aspects of the present invention, the valve assembly employing the valve member of Figs. 7A and 7B with spring wires engaged in the channel defined in the valve member; and

[0018] [Fig.9A] and [Fig.9B] are cross-sectional side views of another embodiment of a valve assembly in closed and open configurations respectively, illustrating a linear spring coupled in a closure mechanism with a connecting member, according to aspects of the present invention. DETAILED DESCRIPTION

[0019] The present invention describes valve assemblies that can be used in subterranean wellbore systems. In particular, flapper valve assemblies are described that utilize spring wires on opposite lateral sides of a flapper element, which cooperatively bias the flapper element toward a closed position. The spring wires provide sufficient torque to ensure robust operation of the flapper element and allow sufficient fluid flow through the limited available space through the valve assembly. A symmetrical pair of spring wires can be robustly manufactured and individually installed without unnecessary accumulation of tolerances or manufacturing errors, to provide predictable torque to the flapper element.The spring wires may be secured in blind holes or other features defined in the valve element, to ensure that the springs remain engaged with the valve element throughout operation of the valve assembly.

[0020] [Fig.l] illustrates a wellbore system 10 according to exemplary embodiments of the present invention. In the wellbore system 10, a wellbore 12 extends from a surface location "S" through a geological formation "G". In some embodiments, the surface location "S" may be an onshore location as illustrated, and in other embodiments, the surface location "S" may be an offshore seabed, without departing from the scope of the invention. A casing string 16 may be cemented into the wellbore 12 to provide structural support and prevent collapse of the walls of the wellbore 18. Aspects of the invention may also be practiced in uncased or open-hole portions of the wellbore 12. The wellbore 12 intersects a hydrocarbon-producing formation 20 from which fluids 22 may be produced.A production string 26 extends between the hydrocarbon-producing formation 20 and the surface location "S" and provides a conduit for communicating fluids 22 to the surface location "S". A wellhead 28 at the surface location "S" includes one or more valves 30 for controlling the flow rate and distribution of fluids 22 received from the wellbore 12.

[0021] The wellbore system 10 further includes a valve assembly 100 disposed at a subterranean location within the wellbore 12. The valve assembly 100 is interconnected within the production string 26 and may alternatively be coupled within other types of wellbore casing strings, in other embodiments (not shown). The valve assembly 100 is operable between an open configuration, in which the flow of fluids 22 through the production string 26 is permitted, and a closed configuration in which the flow of fluids is prevented. A control line 32 extends from the valve assembly 100 to a controller 33 in the wellhead 28 or to another remote location where communication with the valve assembly 100 may be necessary. As illustrated, the control line 32 extends within an annulus 34 defined radially between the production string 26 and the casing string 16. In other embodiments, the control line 32 could alternatively be arranged within the production string 26, or otherwise formed in a sidewall of the production string 26.

[0022] The control line 32 may facilitate maintaining the valve assembly 100 in the open configuration during nominal operations, and closing the valve assembly 100 in the event of an emergency or hazardous condition at the surface location "S". For example, the control line 32 may include a hydraulic conduit that provides hydraulic pressure to the valve assembly 100 to maintain the valve assembly 100 in the open configuration. Reducing or eliminating the hydraulic pressure may operate to close the valve assembly 100 in response to instructions from an operator, or automatically in response to a predetermined wellbore condition.

[0023] Referring to [Fig. 2A], the valve assembly 100 includes a generally tubular body 102 extending along a longitudinal axis A1. The tubular body 102 defines a first end 102a and a second end 102b and is interconnectable within the production tubing 26 ([Fig. 1]), such that the first end 102a is disposed upstream of the second end 102b. A flow path 104 is defined along the longitudinal axis A1 through the production tubing 26 and the tubular body 102. A valve member 106 is pivotally coupled to the second end 102b of the tubular body 102 about a pivot axis A2. The valve member 106 is movable between the open and closed positions within the valve assembly 100.Most particularly, the valve member 106 is movable between the illustrated closed position, in which the valve member 106 engages a valve seat 108 obstructing the flow path 104, and an open position (see [Fig. 9B]) in which the valve member 106 pivots away from the valve seat 108, such that flow through the valve seat 108 is permitted. In some embodiments, the open position of the valve member 106 is generally orthogonal to the closed position of the valve member 106 (see [Fig. 9B]). For example, an axial face 110 of the valve member 106 may be oriented in a lateral direction when the valve member is rotated toward the open position about the pivot axis A2.

[0024] The flow path 104 extends through a fixed opening 112 defined through the valve seat 108. As illustrated, the fixed opening 112 is generally circular and centered about the longitudinal axis AL. Other geometries for the fixed opening 112 are contemplated within the scope of the invention. The flow path 104 extends from the fixed opening 112 along a cylinder 114 defined about the axis Al. and having a diameter D similar to the diameter D of the fixed opening 112. Generally, the valve assembly 100 is arranged so that the flow path 104 along the cylinder 114 is not obstructed when the valve member 106 is in the open position, so as not to impede the flow of fluid therethrough.

[0025] The valve assembly 100 includes a closure mechanism 116 that communicates a biasing force to the valve member 106, thereby urging the valve member 106 toward the valve seat 108. The closure mechanism 116 includes a spring wire 120 and a spring support 122 fixedly coupled to the tubular body 102. The spring support 122 includes a pair of side arms 124, 126 extending axially from the tubular body 102. A first end 122a of the spring support 122 is coupled to the tubular body 102 by fasteners 128, which may include screws, pins, threads, and the like. A second end 122b of the spring support 122 includes a circumferential cross member 130 coupling the side arms 124, 126 together.The crossmember 130 provides rigidity to the spring support 122 and extends circumferentially around the cylinder 114, such that the flow path 104 is not obstructed by the crossmember 130.

[0026] The spring wire 120 is axially constrained between the spring support 122 and a saddle 132 defined in the axial face 110 of the valve member 106. The saddle 132 is a curved groove extending laterally on the axial face 110 at a radial distance RI from the pivot axis A2. A first end 120a of the spring wire 120 engages the saddle 132 to impart torque to the valve member 106 about the pivot axis A2. The curved shape of the saddle 132 allows the saddle 132 to maintain engagement with the spring wire 120 as the valve member 106 pivots about the axis A2. At a second end 120b of the spring wire 120, the side arms 124, 126 of the spring support 122 provide a base against which the spring wire 120 can extend to impart a force to the valve member 106 to close the valve assembly 100.Generally, larger radial distances RI from the pivot axis A2 allow the closure mechanism 116 to provide greater torque to the valve member 106. However, larger radial distances RI may also require more complex closure mechanisms and / or closure mechanisms that occupy more of the limited space in a downhole valve assembly.

[0027] As illustrated in [Fig.2B], the spring wire 120 is generally made from a single strand of wire with a generally circular cross-section. The spring wire 120 may be made as a wire-like spring devoid of any coil or cylindrical structure that might impinge on the flow path 104. A straight wire segment 134 extends laterally through the spring wire 120 at a first end 120a of the spring wire 120. The straight wire segment 134 rolls inside the saddle 132 ([Fig.2A]) as the valve member 106 pivots between the open and closed positions. Extending from the straight wire segment 134 are generally symmetrical shoulder curves 136, 138 and side arms 140, 142. The side arms 140, 142 are comprised of straight sections 140a, 142a, major curves 140b, 142b, minor curves 140c, 142c, and straight sections 140d, 142d terminating in respective free ends 144, 146 at a second end 120b of the spring wire 120. The major curves 140b, 142b and minor curves 140c, 142c of the side arms 140, 142 provide flexibility to the spring wire 120, and specifically allow the spring wire 120 to be axially compressed (by bringing the free ends 144, 146 together with the straight wire segment 134).Thus, when the free ends 144, 146 are axially retained by the spring support 122 ([Fig. 2A]), the spring wire 120 may transmit an axial force to the valve member 106 ([Fig. 2A]). In some embodiments, the free ends 144, 146 may have end caps (not shown) or other features installed thereon to facilitate attachment of the free ends 144, 146 to the spring support 122.

[0028] The spring wire 120 has a relatively complex geometry, in order to provide sufficient axial force to reliably close the valve member 100 without impinging on the flow path 104. For example, the side arms 140, 142 of the spring wire 120 are not coiled, but are generally defined in a single plane, so that the side arms 140, 142 do not interfere with the pivotal movement of the valve member 106 or the flow of fluids through the flow path 104. Wire-shaped springs such as the spring wire 120 are generally made with automated presses and manual bending equipment. The wire-shaped springs are bent to include concavities and other features in their geometry that allow the spring to store energy.This complex geometry can sometimes lead to manufacturing difficulties and tolerance stacking that can cause the spring wire 120 to behave unexpectedly. For example, if the side arms 140, 142 are not exactly symmetrical, the spring wire 120 may tend to twist. If each of the sections, for example, 134, 136, 138, 140, 142 of the spring wire 120 is made to a predefined tolerance, defined for the particular section, but if the cumulative effect of manufacturing errors causes errors to accumulate throughout the spring wire 120, the spring wire may behave erratically, including pulling out of the saddle 132 of the valve member 106.

[0029] Referring to [Fig. 3], another embodiment of a spring wire 150 includes resistance bands 152 supported on a straight wire segment 154 thereof. ci. The spring wire 150 may be formed as a wire-like spring in the same general shape as the spring wire 120 ([Fig. 2B]) described above. The resistance bands 152 may be made of strips of rubber, molded elastomers, or other suitable materials to increase a frictional resistance between the straight wire segment 154 and the saddle 132 of a valve member 106 ([Fig. 2A]). As illustrated, three laterally spaced resistance bands 152 are provided, and in other embodiments, any number of resistance bands 152 is contemplated. The resistance bands 152 may help keep the straight wire segment 154 engaged in the saddle 132, particularly when the valve member 106 is in the open position within the valve assembly 100.The high lateral forces provided by the spring wire 150 could otherwise cause the straight wire segment 154 to slide out of the saddle 132 when the valve member 106 is rotated to the open position where the axial face 110 of the valve member 106 faces in a lateral direction.

[0030] [Fig.4] illustrates another embodiment of a valve element 160 including a plurality of saddle grooves 162 defined in a saddle 164 thereof. The saddle grooves 162 extend laterally through the saddle 164 and increase the frictional resistance between the saddle 164 and a straight wire segment 134 ([Fig.2B]) 154, ([Fig.3]) of a spring wire 120, 150. The poppet member 160 may be installed in place of the poppet member 106 in the valve assembly 100 and may be used with either of the spring wires 120, 150.

[0031] Referring to [Fig.5A], another embodiment of a valve assembly 200 is illustrated, which may be employed in the wellbore system 10 of [Fig.1]. The valve assembly 200 includes a poppet member 202 biased toward a closed position with a pair of opposing spring wires 204, 206. The poppet member 202 includes a pair of opposing blind holes 212, 214 defined in an outer circumferential surface 216 thereof, and each of the blind holes 212, 214 receives a free end 204a, 206a ([Fig.5B]) of one of the opposing spring wires 204, 206. The blind holes 212, 214 retain the free ends 204a, 206a in axial and radial directions, and are sized to provide freedom of rotation of the free ends 204a, 206a relative to the poppet member 202 about an axis A3. The axis A3 defined by the blind holes 212, 214 is generally parallel to the pivot axis A4.In some embodiments, a resistance band (see [Fig.3]), end cap, or non-metallic washer may be attached to the spring wires 204, 206 adjacent the respective free ends 204a, 206a, to provide a secure fit in the blind holes 212, 214. The resistance bands, end caps, or non-metallic washers may prevent the spring wires 204, 206 from disengaging from the valve member 202 during operation.

[0032] The axis A3 extends through the blind holes 212, 214 and is radially spaced from the pivot axis A4 about which the valve member 202 pivots. The valve assembly 200 may use the same generally tubular body 102 and spring support 122 as described above for use with the valve assembly 100 ([Fig. 2A]). The valve member 202 is movable between the illustrated closed position, in which the valve member 202 engages the valve seat 108, and an open position in which the valve member 202 pivots away from the valve seat 108. The pair of opposing spring wires 204, 206 may be implemented as wire-like springs lacking any coil or cylindrical structure.The spring wires 204, 206 may have mirror symmetry, allowing the spring wires 204, 206 to cooperate to impart a biasing force to the valve member 202, thereby urging the valve member 202 toward the valve seat 108 and the closed position.

[0033] As illustrated in [Fig.5B], the opposing spring wires 204, 206 each include a straight wire segment 222, 224 terminating in a respective free end 204a, 206a. The free ends 204a, 206a may roll within the blind holes 212, 214 as the valve member 202 pivots between the open and closed positions. The opposing spring wires 204, 206 may include shoulder curves 218, 220 and side arms 222, 224 identical to the shoulder curves 136, 138 and side arms 140, 142 of the spring wire 120 ([Fig.2B]), as described above. The pair of opposing spring wires 204, 206, however, is not as susceptible to the manufacturing and operating difficulties of the spring wire 120 described above.

[0034] The opposing spring wires 204, 206 have a simpler geometry than the spring wire 120, and thus, lower tolerances and higher manufacturing accuracy can be achieved. Not all manufacturing errors will be accumulated to the same degree, and thus the structural behavior of the pair of opposing spring wires 204, 206 can be more predictable and the design can be more easily analyzed, adjusted, and scaled for different valve sizes and loading conditions. A higher level of torque can thus be provided to the poppet member 202 to maintain the valve assembly 200 in a closed configuration. Additionally, since the free ends 204a, 206a may be secured in the axial and radial directions in the blind holes 212, 214, the spring wires 204, 206 may not be as likely to disengage from the valve member 202 in operation.

[0035] Referring now to [Fig. 6], a valve member 230 is illustrated which may be used in place of the valve member 202 in the valve assembly 200 ([Fig. 5A]). The valve member 230 is saddle-free, which may simplify the machining operations in the construction of a valve assembly. The blind holes 232, 234 extend from the lateral openings 232a, 234a in an outer circumferential surface 236 of the valve member 230 to a hole depth HD. In some embodiments, the hole depth HD is chosen so that the free ends 204a, 206a of the spring wires 204, 206 ([Fig.5B]) can abut a lower surface of the blind holes 232, 234. In this way, a predetermined lateral position of the spring wires 204, 206 can be maintained. In some embodiments, the hole depth HD can be chosen so that the free ends 204a, 206a do not reach the lower surface of the blind holes 232, 234.

[0036] Referring to Figures 7A and 7B, another embodiment of a valve member 302 is illustrated for use in a valve assembly 300 ([Fig. 8A]). The valve member 302 includes a channel 304 defined therein for receiving the free ends of the spring wires 306 ([Fig. 8A]). The channel 304 extends through a central rib 308 of the valve member 302 that projects beyond shoulders 310 on either lateral side of the central rib 308. The channel 304 is generally parallel to and radially offset from a pair of pivot holes 312 defining a pivot axis A5 of the valve member 302. An axial force F1 applied through the channel 304 may cause the valve member 302 to pivot about the pivot axis A5. The channel 304 is elongated in a radial direction, which may facilitate pivoting of the valve member 302 with the spring wires 306 engaged.

[0037] Referring to Figures 8A and 8B, the valve assembly 300 includes a generally tubular body 314, which may be interconnected in the production string 26 ([Fig.l]), the valve member 302, and a closure mechanism 318. The closure mechanism 318 includes a spring support 320 fixedly coupled to the tubular body 314 and a pair of spring wires 322, 324 that may be decoupled from each other. A flow path 326 is defined along a longitudinal axis A6 through the tubular body 314, which is closed with the valve member 302 in the illustrated closed position. The valve member 302 is pivotably coupled to the spring support 320 such that the valve member 302 can pivot to an open configuration, in which the flow path 326 is not obstructed.

[0038] The closure mechanism 318 imparts a biasing force to the valve member 302, thereby urging the valve member 302 toward the illustrated closed position. The pair of spring wires 322, 324 are engaged with the valve member 302, such that the free ends 322a, 324a are disposed within the channel 304 and are axially constrained by the central rib 308. The free ends 322a, 324a are free to rotate relative to the valve member 302 and can slide along of the elongated channel 304 when the valve member 302 pivots. The spring wires 322, 324 are illustrated in a relaxed configuration where the free ends 322b, 324b are disengaged from the spring holder 320. In the relaxed configuration, when the free ends 322a, 324a at a first end of the spring wires 322, 324 are received in the channel 304, the free ends 322b, 324b at a second end of the spring wires are displaced axially and laterally relative to the axial holes 338, 340 defined in the spring holder 320. In an operative configuration, the free ends 322b, 324b may be installed in the axial holes 338, 340 to preload the spring wires 322, 324 between the spring holder 320 and the valve member 302 such that the spring wires 322, 324 push the valve element toward the closed configuration.

[0039] The spring support 320 extends axially along the longitudinal axis A6 and includes a pair of side arms 330, 332 axially spaced from the valve member 302. A circumferential cross beam 334 couples the side arms 330, 332 together. The circumferential cross beam 334 extends circumferentially around the flow path 326 between the side arms 330, 332 such that the flow path 326 is not obstructed. The side arms 330, 332 each include an axial hole 338, 340 defined therein for receiving a free end 322b, 324b of the spring wires 322, 324. The axial holes 338, 340 are positioned such that the spring wires 322, 324 can be axially compressed between the side arms 330, 332 and the valve member 302 when the free ends 322b, 324b are received therein.The spring wires 322, 324 may also be shaped such that the spring wires 322, 324 are laterally compressed between the spring support 320 and the valve member 302 when the free ends 322b, 324b are engaged in the axial holes 338, 340. The lateral compression of the springs 322, 324 may serve to maintain the free ends 322a, 324a within the channel 304.

[0040] The decoupled spring wires 322, 324 may be installed individually by first installing the free ends 322a, 324a in the channel 304 and then installing the free ends 322b, 324b in the axial holes 338, 340. The decoupled spring wires 322, 324 may be installed individually without permanently deforming the spring wires 322, 324. A combination spring (not shown) that would be formed if the free ends 322a, 324a were joined would not be as easily installed through the channel 304 without permanently deforming the spring and would not provide as reliable and predictable a closing force to the valve member 302.

[0041] Referring now to Figures 9A and 9B, a valve assembly 400 is illustrated in closed ([Fig.9A]) and open ([Fig.9B]) configurations. The valve assembly 400 may be interconnected in the production tubing 26 ([Fig.1]) and generally includes a tubular body 402, a valve member 404, and a closure mechanism 406 that biases the valve member 404 toward the closed configuration. The tubular body 402 defines a longitudinal axis A7 and a flow path 408 extending therethrough. The valve member 404 pivots about a pivot axis A8 and engages a valve seat 410 in the closed configuration. One or more side openings 412 are defined in the valve member 404 for engaging the closure mechanism 406. The side openings 412 may be defined in an outer circumferential surface of the valve member 404 (similar to the blind holes of the valve member 230, [Fig. 6]) or in a central rib of the valve member 404 (similar to the channel 304 of the valve member 302, [Fig. 7A]). The side openings 412 may be defined at a radial distance R2 from the pivot axis A8.In some embodiments, the radial distance R2 may be large enough that the side openings 412 are defined generally at the center of the valve member 404 or further from the pivot axis A8.

[0042] The closure mechanism 406 includes a spring support 414 extending axially from the tubular body 402. The spring support 414 may be fixedly coupled to the tubular body 402 and define a fixed reference support 416 thereon. The spring support 414 may include side arms and a circumferential cross member similar to the spring support 122 ([Fig. 2A]) or 320 ([Fig. 8A]). In some embodiments, the fixed reference support 416 may include a feature defined on one of the side arms similar to the axial holes 328 ([Fig. 8A]).

[0043] Coupled between the valve member 404 and the fixed reference support 416, the closure mechanism 406 includes one or more connecting members 420, a hinge 422, and a biasing member 424. At a first end 420a of the one or more connecting members 420, the connecting members 420 are pivotally coupled to the valve member 404 at the one or more side openings 412. In some embodiments, a pair of opposing side openings 412 may receive respective free ends of a pair of individual connecting members 420 such that the free ends may rotate within the side openings 412. In other embodiments, a connecting member may be threaded through a channel defined in the valve member (see [Fig.7B]).The connecting members 420 may be generally rigid or may be flexible in operation, and may include any of the spring wires 204, 206, 306, 322, 324 described herein. A second end 420b of the one or more connecting members 420 is coupled to the hinge 422. The hinge 422 may be formed as a disc with a central rotation ring therein. The hinge 422 pivotally couples the one or more connecting members 420 to the biasing member 424. The member . biasing member 424 is supported between the fixed reference support 416 and the hinge 422, and may include a linear coil spring, a stack of spring washers, or another axially compressible structure.

[0044] As illustrated in [Fig.9A], when the valve assembly 400 is in the closed configuration, the biasing member 424 is axially extended against the fixed reference support 416 to maintain the hinge 422 and the second end 420b of the one or more connecting members 420 at a location axially spaced from the fixed reference support 416. A force F2 provided by the biasing member 424 is transferred through the one or more connecting members 420 to the valve member 404 to maintain the valve member 404 in engagement with a valve seat 426. When the valve assembly 400 is moved to an open configuration ([Fig.9B]), for example with a hydraulically actuated flow tube (not shown), the biasing member 424 is axially compressed against the fixed reference support 416.The hinge 422 and the second end 420b of the one or more connecting members 420 are moved to an axially approximate location relative to the fixed reference support 416 allowing the valve member 404 to pivot to a position that is generally orthogonal to the position of the valve member 404 in the closed configuration. In this orthogonal position, the valve member 404 does not impinge on the flow path 408 defined by the tubular body and extending into the spring support 414.

[0045] The aspects of the invention described below are provided to describe a selection of concepts in simplified form that are described in more detail above. This section is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used to assist in determining the scope of the claimed subject matter.

[0046] According to a first aspect, the invention relates directly to a downhole valve assembly.The assembly includes a tubular body defining a longitudinal axis and a flow path therethrough, a valve member pivotally coupled to the tubular body about a pivot axis and movable between a closed position where the valve member prevents fluid flow through the flow path and an open position where fluid flow through the flow path is permitted, the valve member including a pair of opposed side openings defined therein radially spaced from the pivot axis, a spring support coupled to the tubular body and extending axially along the longitudinal axis, and a pair of opposed spring wires each individually coupled between the spring support and the valve member, the spring wires each including a free end retained in a respective one of the side openings defined in the valve member.

[0047] In one or more embodiments, the pair of opposing spring wires are formed as wire-like springs devoid of coils and cylindrical structures. The pair of opposing spring wires may have mirror symmetry with respect to each other.

[0048] In some embodiments, the pair of opposing spring wires each includes a non-metallic resistance band thereon engaging the valve member. In some embodiments, the side openings are defined on an outer circumferential surface of the valve member extending into opposing blind holes, and the free ends of the spring wires may be retained in the side openings each abutting a bottom surface of a respective one of the opposing blind holes. In some embodiments, the side openings are defined on an elongated channel extending through a central rib of the valve member.

[0049] In one or more embodiments, the spring support includes a pair of side arms connected by a circumferential cross member, and each of the pair of opposing spring wires is supported in a hole provided in a respective one of the side arms of the spring support. Free ends of the spring wires opposite the free ends retained in the side openings of the valve member may be axially and laterally spaced from the holes in the spring support when the spring wires are in a relaxed configuration. In some embodiments, the assembly further includes a linear spring and a hinge coupled between the spring wires and the spring support.

[0050] In another aspect, the invention relates to a wellbore system. The wellbore system includes a tubular string disposed at a downhole location in a wellbore, a tubular body coupled within the tubular string, the tubular body defining a longitudinal axis and a flow path therethrough, a valve member pivotally coupled to the tubular body about a pivot axis and movable between a closed position where the valve member prevents fluid flow through the flow path and an open position where fluid flow through the flow path is permitted, the valve member including a pair of opposed side openings defined therein radially spaced from the pivot axis, a spring support coupled to the tubular body and extending axially along the longitudinal axis,and a pair of opposing spring wires each individually coupled between the spring support and the valve member, the spring wires each including a free end retained in a respective one of the side openings defined in the valve member.

[0051] In some embodiments, the pair of opposing spring wires are mirror-symmetrical to each other and are formed as springs. wire form devoid of coils and cylindrical structures. The side openings may be defined on an outer circumferential surface of the valve member extending into opposed blind holes and wherein the free ends abut a bottom surface of a respective one of the opposed blind holes. In some embodiments, the side openings are defined on an elongated channel extending through a central rib of the valve member.

[0052] In one or more embodiments, the spring support includes a pair of side arms connected by a circumferential cross member, and wherein each of the pair of opposing spring wires is supported in a hole provided in a respective one of the side arms of the spring support. Free ends of the spring wires opposite the free ends retained in the side openings of the valve member may be axially and laterally spaced from the holes in the spring support when the spring wires are in a relaxed configuration. In some embodiments, the system further includes a linear spring and a hinge coupled between the spring wires and the spring support.

[0053] In another aspect, the invention relates to a method of making a downhole valve assembly.The method includes pivotally coupling a valve member to a tubular body such that the valve member is movable between a closed position where the valve member prevents fluid flow through a flow path defined by the tubular body and an open position where fluid flow through the flow path is permitted, attaching a spring holder to the tubular body, the spring holder extending axially from the tubular member and circumferentially around the flow path, retaining the free ends of a pair of opposing spring wires in a respective one of a pair of opposing side openings defined in the valve member, and preloading each of the spring wires between the spring holder and the valve member such that the spring wires cooperate to bias the valve member toward the closed position.

[0054] In one or more aspects, the method further includes forming the spring wires as wire-shaped springs devoid of coils and cylindrical structures such that the spring wires have mirror symmetry with respect to one another. In some embodiments, preloading each of the spring wires includes installing the free ends of the spring wires opposite the free ends retained in the side openings of the valve member into holes defined in the spring holder.

[0055] The abstract of the invention is intended only to provide the Patent Office and the general public with a means of quickly determining, from a cursory reading, the nature and gist of the technical description, and this represents only one or several examples.

[0056] Although various examples have been illustrated in detail, the description is not limited to the examples shown. Modifications and adaptations of the above examples may occur to those skilled in the art. Such modifications and adaptations are within the scope of the invention.

Claims

Claims

1. A downhole valve assembly (100, 200, 300, 400), characterized in that it comprises: a tubular body (102, 314, 402) defining a longitudinal axis and a flow path (104, 326, 408) therethrough; a valve member (106, 160, 202, 230, 404, 302) pivotably coupled to the tubular body (102, 314, 402) about a pivot axis and movable between a closed position where the valve member (106, 160, 202, 230, 404, 302) prevents fluid flow through the flow path (104, 326, 408) and an open position where fluid flow through the flow path (104, 326, 408) is permitted, the valve member (106, 160, 202, 230, 404, 302) including a pair of opposing side openings (232a, 234a, 412) defined inside it radially spaced from the pivot axis;a spring support (122, 320, 414) coupled to the tubular body (102, 314, 402) and extending axially along the longitudinal axis; and a pair of opposed spring wires (120, 150, 204, 206, 306, 322, 324) each individually coupled between the spring support (122, 320, 414) and the valve member (106, 160, 202, 230, 404, 302), the spring wires (120, 150, 204, 206, 306, 322, 324) each including a free end (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) retained in a respective one of the side openings (232a, 234a, 412) defined in the valve member (106, 160, 202, 230, 404, 302).;

2. The assembly (200) of claim 1, wherein the pair of opposing spring wires (204, 206) are formed as wire-shaped springs devoid of coils and cylindrical structures.

3. The assembly (200) of claim 2, wherein the pair of opposing spring wires (204, 206) are mirror-symmetrical to each other.

4. The assembly (100) of claim 1, wherein the pair of opposing spring wires (150) each includes a non-metallic resistance band (152) thereon engaged with the valve member (106).

5. The assembly (200) of claim 1, wherein the side openings (232a, 234a) are defined on an outer circumferential surface (236) of the valve member (230) extending into opposing blind holes (232, 234).

6. The assembly (200) of claim 5, wherein the free ends (204a, 206a) of the spring wires (204, 206) retained in the side openings (232a, 234a) each abut against a lower surface of a respective one of the opposing blind holes (232, 234).

7. The assembly (300) of claim 1, wherein the side openings are defined on an elongated channel (304) extending through a central rib (308) of the valve member (302).

8. The assembly (100, 300) of claim 1, wherein the spring support (122, 320) comprises a pair of side arms (124, 126, 140, 142, 330, 332) connected by a circumferential cross member (130, 334), and wherein each of the pair of opposing spring wires (120, 150, 306, 322, 324) is supported in a hole provided in a respective one of the side arms (124, 126, 140, 142, 330, 332) of the spring support (122, 320).

9. The assembly (100, 200, 300, 400) of claim 8, wherein the free ends of the spring wires (120, 150, 204, 206, 306, 322, 324) opposite the free ends (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) retained in the lateral openings (232a, 234a, 412) of the valve member (106, 160, 202, 230, 404, 302) are axially and laterally spaced from the holes in the spring support (122, 320, 414) when the spring wires (120, 150, 204, 206, 306, 322, 324) are in a relaxed configuration.

10. The assembly (400) of claim 1, further comprising a linear spring and a hinge (422) coupled between the spring wires and the spring support (414).

11. A wellbore system (10) characterized in that it comprises: a tubular string disposed at a downhole location in a wellbore (12, 18); a tubular body (402) coupled within the tubular string, the tubular body (402) defining a longitudinal axis and a flow path (104, 326, 408) therethrough; a valve member (106, 160, 202, 230, 404, 302) pivotably coupled to the tubular body (102, 314, 402) about a pivot axis and movable between a closed position where the valve member (106, 160, 202, 230, 404, 302) prevents fluid flow through the flow path (104, 326, 408) and an open position where fluid flow through the flow path (104, 326, 408) is permitted, the valve member (106, 160, 202, 230, 404, 302) including a pair of opposed side openings (232a, 234a, 412) defined therein radially spaced from the pivot axis; a spring support (122, 320, 414) coupled to the tubular body (102, 314, 402) and extending axially along the longitudinal axis; and a pair of opposed spring wires (120, 150, 204, 206, 306, 322, 324) each individually coupled between the spring support (122, 320, 414) and the valve member (106, 160, 202, 230, 404, 302), the spring wires (120, 150, 204, 206, 306, 322, 324) each including a free end (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) retained in a respective one of the side openings (232a, 234a, 412) defined in the valve member (106, 160, 202, 230, 404, 302).

12. The system (10) of claim 11, wherein the pair of opposing spring wires (204, 206) are mirror-symmetrical to each other and are formed as wire-like springs devoid of coils and cylindrical structures.

13. The system (10) of claim 11, wherein the side openings (232a, 234a) are defined on an outer circumferential surface (236) of the valve member (230) extending into opposing blind holes (232, 234) and wherein the free ends (204a, 206a) abut a lower surface of a respective one of the opposing blind holes (232, 234).

14. The system (10) of claim 11, wherein the side openings are defined on an elongated channel (304) extending through a central rib (308) of the valve member (302).

15. The system (10) of claim 11, wherein the spring support (122, 320) comprises a pair of side arms (124, 126, 140, 142, 330, 332) connected by a circumferential cross member (130, 334), and wherein each of the pair of opposing spring wires (120, 150, 306, 322, 324) is supported in a hole provided in a respective one of the side arms (124, 126, 140, 142, 330, 332) of the spring support (122, 320).

16. The system (10) of claim 15, wherein the free ends of the spring wires (120, 150, 204, 206, 306, 322, 324) opposite the free ends (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) retained in the lateral openings (232a, 234a, 412) of the valve member (106, 160, 202, 230, 404, 302) are axially and laterally spaced from the holes in the spring support (122, 320, 414) when the spring wires spring (120, 150, 204, 206, 306, 322, 324) are in a relaxed configuration.

17. The system (10) of claim 11, further comprising a linear spring and a hinge (422) coupled between the spring wires and the spring support (414).

18. A method of constructing a downhole valve assembly (100, 200, 300, 400), characterized in that it comprises: pivotally coupling a valve member to a tubular body (102, 314, 402) such that the valve member can be moved between a closed position where the valve member prevents fluid flow through a flow path (104, 326, 408) defined by the tubular body (102, 314, 402) and an open position where fluid flow through the flow path (104, 326, 408) is permitted; attaching a spring support (122, 320, 414) to the tubular body (102, 314, 402), the spring support (122, 320, 414) extending axially from the tubular member and circumferentially around the flow path (104, 326, 408);retaining the free ends (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) of a pair of opposing spring wires (120, 150, 204, 206, 306, 322, 324) in a respective one of a pair of opposing side openings (232a, 234a, 412) defined in the valve member (106, 160, 202, 230, 404, 302); and preloading each of the spring wires (120, 150, 204, 206, 306, 322, 324) between the spring support (122, 320, 414) and the valve member (106, 160, 202, 230, 404, 302) such that the spring wires (120, 150, 204, 206, 306, 322, 324) cooperate to bias the valve member (106, 160, 202, 230, 404, 302) toward the closed position.;

19. The method of claim 18, further comprising constructing the spring wires (204, 206) as wire-shaped springs devoid of coils and cylindrical structures such that the spring wires (204, 206) have mirror symmetry with respect to each other.

20. The method of claim 18, wherein preloading each of the spring wires (120, 150, 204, 206, 306, 322, 324) comprises installing the free ends of the spring wires (120, 150, 204, 206, 306, 322, 324) opposite the free ends (144, 146, 204a, 206a, 322a, 322b, 324a, 324b) retained in the side openings (232a, 234a, 412) of the valve element (106, 160, 202, 230, 404, 302) in holes defined in the spring support (122, 320, 414).

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