Description

Field of the Invention

The present invention relates to valves and specifically subsurface safety valve assembly for controlling fluid flow in a wellbore and more specifically ball subsurface safety valves. These may be for both oil and gas production and wireline applications, but may also be usable in other borehole applications, such as fracking, water wells, etc.

Background to the Invention

In a typical oil and gas well a casing string extends from the ground Surface to a ground formation containing hydrocarbons to be produced. A production tubing string extends within the casing string. A packer is provided downhole to prevent flow of hydrocarbon and other fluids in the annulus between the production tubing string and the casing string. A portion of the casing extends below the packer and the bottom of the production tubing string. Fluid flow is typically from the formation through perforations in the portion of the casing below the packer, into the production string, and through the production tubing string to the wellhead. Fluids may be liquid or gaseous state and may include, among other things, oil, gas, and water. Surface Control Subsurface Safety Valves (“SCSSV”) are used to prevent uncontrolled flow of reservoir fluids through the tubing string. A SCSSV is part of the production tubing string or insertable in the well via wireline. Typically, the SCSSV is positioned at least several hundred feet below the surface of the earth, or in a typical offshore well, several hundred feet below the mudline. A typical SCSSV comprises a single flapper valve that is rotatably disposed within the valve, and rotates downward to an open position, and is failsafe rotated upwardly by a spring, and thereby closed. Usually, the SCSSV comprises an internal sliding cylindrical sleeve or flow tube that is spring biased in an upward direction. When the flow tube is in its uppermost position, it permits the flapper to rotate (under spring bias) to its closed position, blocking the bore of the flow tube and consequently closing the valve. When the flow tube is forced downward against its spring bias and the spring bias of the flapper, the flow tube forces the flapper out of the bore of the valve, thereby opening the valve. Reversal of this procedure moves the flow tube upward, out of the way of the flapper, which then rotates back to its closed position.

It can be appreciated that any upward fluid flow during this closing process tends to force the flapper into its closed position. For hydraulically operated valves, hydraulic pressure is applied down a control line to a fluid chamber in the SCSSV, forcing the flow tube to slide downwards thereby pushing the flapper downwards to open the valve. When hydraulic pressure is removed, the fail-safe closure spring on the flow tube pushes the flow tube back up and exposes the flapper to the flowing fluid, causing the flapper to shut. The flapper will fail-safe shut with no flowing fluid when the sleeve is removed. Flapper valves are susceptible to failure for various reasons including corrosion, sand, slam closures, debris, wireline cuts, and other downhole operating conditions. In prior art SCSSVs, upon failure of the flapper valve, installation of a secondary valve within the SCSSV may be required. Atypical installation of the secondary valve within the SCSSV requires two wireline processes. The first process involves using a wireline tool to lock out the flapper within the SCSSV. The second process involves using a wireline tool to install a secondary valve within the SCSSV.

Summary of the Invention

According to a first aspect of the present invention there is provided a valve comprising a body, the body having an interior bore, an entry aperture, an exit aperture, and a valve member located within the bore and between the entry aperture and exit aperture, a hydraulic sleeve provided within at least part of the body, an internal hydraulic chamber, one or more hydraulic entry ports provided through the body and communicating with the internal hydraulic chamber, the hydraulic sleeve being movable from a first or closed position to a second or open position under the action of hydraulic fluid feed to the internal hydraulic chamber, the hydraulic sleeve being connected to the valve member by a mechanical linkage, wherein a fluid conduit is provided between the internal hydraulic chamber and the valve member.

The fluid conduit may allow a quantity of a hydraulic fluid to pass from the internal hydraulic chamber to the valve member thereby lubricating the valve member.

The hydraulic fluid may flow through the conduit and onto the valve member between the first or closed position and the second or open position.

There may be a hydraulic reservoir located between the internal hydraulic chamber and the valve member. The fluid conduit may comprise an initial fluid conduit between the internal hydraulic chamber and the hydraulic reservoir, the hydraulic reservoir, and a secondary fluid conduit between the hydraulic reservoir and the valve member.

The hydraulic sleeve may provide part of the fluid conduit.

There may be an external hydraulic fluid supply.

In use, a working fluid may flow within the valve when in a non-closed position at a well pressure. It will be understood that in common with most valve types, fluid flow is only prevented in the fully closed position, and fluid flow occurs anywhere between that and the fully open position.

The external hydraulic fluid supply may be supplied to the hydraulic chamber at a hydraulic supply pressure.

The hydraulic supply pressure may exceed the well pressure.

With the hydraulic supply pressure exceeding the well pressure, working fluid is prevented from entering the hydraulic chamber through the fluid conduit.

The internal hydraulic chamber may surround at least part of the bore.

The external hydraulic sleeve may surround at least part of the bore.

There may be provided two valve seats within the central bore which the valve member is seated and is rotatable. The fluid conduit may run from the internal hydraulic chamber to one or both valve seats.

The valve member may be a valve ball.

The valve member may be a butterfly, diaphragm, gate, pinch, piston, or plug type.

The mechanical linkage may be a yoke.

The mechanical linkage may be a rack and pinion mechanism.

The mechanical linkage may be two rack and pinion mechanisms.

The two rack and pinion mechanisms may be located on opposite sides of the body.

The mechanical linkage may be a trunnion.

The fluid conduit may run at least partly through the body.

A spring bias may be provided which biases the sleeve into the first or closed position.

The spring bias may be a coil spring.

The coil spring may be located within the body. Brief of the

Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which:

Fig. 1 is a perspective view of a valve according to the present invention;

Fig. 2 is a side elevation of the valve of Fig. 1 ;

Fig. 3 is a part-sectional plan elevation of the valve of Fig. 1 in the closed position;

Fig. 4 is a part-sectional side elevation of the valve of Fig. 1 in the open position;

Fig. 5 is a perspective partially exploded detail view of the valve of Fig. 1 ;

Fig. 6 is a perspective partially exploded detail sectional view of the valve of Fig. 1 ;

Fig. 7 is a perspective view of a valve member housing of the valve of Fig. 1 ;

Fig. 8 is a perspective detail view of the valve of Fig. 1 ;

Fig. 9 is a perspective part-sectional detail view of the valve of Fig. 1 ; Fig. 10 is a further perspective part-sectional detail view of the valve of Fig. 1 in a first or closed position;

Fig. 11 is a further perspective part-sectional detail view of the valve of Fig. 1 in a second or open position;

Fig. 12 is a perspective view of an alternative embodiment valve member housing compatible with the valve of Fig. 1 ; and

Fig. 13 is a perspective view of an alternative embodiment mechanical linkage compatible with the valve of Fig. 1 .

Referring to the drawings and initially to Fig. 1 there is depicted a first embodiment valve according to the present invention generally referred to as 10.

The valve 10 comprises a body 12, the body 12 having an interior bore 14, an entry aperture 16, an exit aperture 18, and a valve member 20 located within the bore 14 and between the entry aperture 16 and exit aperture 18, a hydraulic sleeve 22 provided within at least part of the body 12, an internal hydraulic chamber 24, one or more hydraulic entry ports 26 provided through the body 12 and communicating with the internal hydraulic chamber 24, the sleeve 22 being movable from a first or closed position to a second or open position under the action of hydraulic fluid feed to the internal hydraulic chamber 24, the hydraulic sleeve 22 being connected to the valve member 20 by a mechanical linkage 28, wherein a fluid conduit is provided between the internal hydraulic chamber 24 and the valve member 20. An external hydraulic fluid supply (not shown) attaches to the valve 10 to supply it and specifically the internal hydraulic chamber 24 via the ports 26 with hydraulic fluid. This may be of a known type, provided that it also has a lubricating quality as well as a suitability to be used as a hydraulic fluid.

The valve member 20 is a ball valve member 20 in the present embodiment, although it will be appreciated by the skilled addressee that other types of valve member 20 may be used, such as butterfly, diaphragm, gate, pinch, piston, plug type, etc.

Two valve seats 32 are provided on the interior bore 14 in which the valve member 20 is mounted and is rotatable about.

The body 12 is formed from several individual modular sections which are attached together to form an elongate cylindrical form. The body 12 has a leading edge 34 (generally the right-hand side of the Figs) and a trailing edge 36 (generally the left-hand side of the Figs).

A front portion 38 is provided at the leading edge 34 and comprises a generally cylindrical form with a leading cylindrical socket portion 40, a greater diameter central portion 42 and a trailing edge elongate shaft 44. The diameter of the socket portion 40 and elongate shaft 44 are less than that of the central portion 44. The socket portion 40 will face downward into the wellbore (not shown).

An inner leading edge sleeve 39 is provided partly within the front portion

38 and is slidable within a cavity 41 provided within the front portion. The inner leading edge sleeve 39 comprises an initial elongate lesser diameter portion 43 located towards the leading edge 34, and a greater diameter boss portion 45 towards the trailing edge 36. The initial elongate lesser diameter portion 43 sits within the cavity 41 , whereas the boss portion 45 is external to and abuts the trailing edge elongate shaft 44. This limits the extent to which the inner leading edge sleeve 39 is may enter the front portion 38.

A valve member housing 46 fits on the end of the front portion 38 and attaches into the central bore 14 of the trailing edge elongate shaft 44. The valve member housing 46 is composed of two identical submembers 47 (towards the leading edge 34 of the valve 10) and 49 (towards the trailing edge 36 of the valve 10) which are attached together with brackets 51. The brackets 51 are located adjacent the mechanical linkage 28. The valve member housing 46 is generally cylindrical with a leading edge cylindrical boss portion 48 which fits into the elongate shaft 44. A central valve member housing portion 50 extends from the cylindrical boss portion 48. The valve member housing portion 50 has a greater external diameter than the leading edge cylindrical boss portion 48, being approximately the same as the elongate shaft 44. The valve member housing portion 50 contains the valve member 20 and the valve seats 32. The mechanical linkage 28 is provided on either side of the valve member housing portion 50. A trailing edge boss portion 52 extends from the valve member housing portion 50. The valve member housing portion 50 has a partly curved and partly flat outer profile, with a flat upper and lower profile 53 upon which the brackets 51 and mechanical linkage 28 are seated. The valve seats 32 are formed in the flat upper and lower profiles 53 with a valve spindle 21 projecting upwardly from the valve member 20 from the flat upper and lower profile. Two curved outer sidewalls 43 connect the flat upper and lower profiles 53.

The mechanical linkage 28 in the first embodiment is a yoke-type linkage 28. A linkage aperture 29 is provided on the upper and lower portions of the valve member 20. Upper and lower linkage pins 31 are provided which cooperate with the linkage aperture 29. Upper and lower connecting rods 33 span the valve member housing portion 50 and are connected to the hydraulic sleeve 22 which drives the upper and lower connecting rods 33 towards and back to rotate the valve member 20 from open to closed positions. The upper and lower connecting rods 33 are generally elongate bars, with a slightly curved outer portion to fit within the body 12. The leading edge of the connecting rods 33 are attached to the boss portion 45 of the inner leading edge sleeve 39. Thus, the hydraulic sleeve 22, the connecting rods 33 and the inner leading edge sleeve 39 may reciprocate back and forward within the body 12 as the valve member 20 is opened and closed. The inner leading edge sleeve 39 acts to stabilise the leading edge of the mechanism.

The hydraulic sleeve 22 is provided around the trailing edge boss portion 52. The hydraulic sleeve 22 comprises a flanged leading edge portion 54 and a lesser external diameter central hydraulic sleeve portion 56. A trailing edge sleeve boss portion 58 extends from the central hydraulic sleeve portion 56. The trailing edge sleeve boss portion 58 comprises an initial greater diameter portion 60 and a second lesser diameter portion 62.

An external cover sleeve 64 is attached to the front portion 38, the leading edge 66 of which abuts the greater diameter central portion 42 and the trailing edge 68 of which surrounds the leading edge cylindrical boss portion 48 and abuts the central valve member housing portion 50 of the valve member housing 46. The external cover sleeve provides a uniform exterior diameter for the body 12 and a cover for the various internal components.

A hydraulic chamber piston 70 is provided around the trailing edge sleeve boss portion 58. The hydraulic chamber piston 70 is a generally cylindrical sleeve comprising a greater diameter leading edge portion 72 which fits around the trailing edge sleeve boss portion 58 and a lesser diameter trailing edge portion 74 connected by a transitional frustum portion 76. A piston sleeve shoulder 78 is provided within the hydraulic chamber piston 70 adjacent the lesser diameter trailing edge portion 74 and the transitional frustum portion 76. The piston sleeve shoulder 78 abuts the trailing edge 23 of the hydraulic sleeve 22.

A spring housing 80 is connected to the valve member housing 46 around the trailing edge boss portion 52. An initial cylinder portion 82 of the spring housing 80 fits around the trailing edge boss portion 52 and houses the hydraulic chamber piston 70. An internal lip 84 is provided around the interior bore 14 of the spring housing which separates the initial cylinder portion 82 from the remainder of the spring housing. The lip 84 is a chamfered flange with an O-ring seal 85 provided at its centre within a seal slot 88.

A central connector 100 is provided around the lesser external diameter central hydraulic sleeve portion 56 and connects the spring housing portion 80 to the external cover sleeve 64. The central connector 100 comprises a leading edge boss 102 which fits within external cover sleeve 64 and a trailing edge boss portion 104 which fits within the spring housing portion 80. A central webbed portion 106 is abutted on either side by the external cover sleeve 64 and the spring housing portion 80. Grub screws 108 are used to attach the central connector 100 external cover sleeve 64 and the spring housing portion 80. An O-ring seal 110 is provided in a seal groove 112 surrounding the central webbed portion 106.

The internal hydraulic chamber 24 is defined by the initial cylinder portion 82 of the spring housing as its exterior, the central hydraulic sleeve portion 56 of the hydraulic sleeve 22 as its interior, the trailing edge boss portion 104 as its leading edge and the greater diameter leading edge portion 72 as its trailing edge portion.

As the internal hydraulic chamber 24 is pressurised with hydraulic fluid through the ports 26, the chamber 24 expands and the hydraulic chamber piston 70 is urged towards the trailing edge 36, which in turn urges the hydraulic sleeve 22, the upper and lower connecting rods 33 and the inner leading edge sleeve 39 towards the trailing edge 36 of the valve 10, thereby rotating the valve member 20 into the open position. As can be seen from the Figs, the internal hydraulic chamber 24 surrounds a part of the bore 14; furthermore, the hydraulic sleeve 22 surrounds a part of the bore 14.

An initial fluid conduit portion 30a is provided between the outside of hydraulic sleeve 22 and the interior of the connector 100. As there is a sliding fit, there is a slight gap through which hydraulic fluid may pass. A hydraulic reservoir 114 is defined distally from internal hydraulic chamber 24 between the leading edge boss 102 at its trailing edge, the hydraulic sleeve 22 as its interior, the external cover sleeve 64 as its exterior and the flanged leading edge portion 54 of the hydraulic sleeve as its leading edge portion. Hydraulic fluid flows from the port 26, through the internal hydraulic chamber 24, along the initial fluid conduit portion 30 and collecting in the hydraulic reservoir 114.

A secondary fluid conduit portion 30b is provided between the hydraulic reservoir 114 and the valve member 20. As there is a sliding fit, there is a slight gap through which hydraulic fluid may pass. The secondary fluid conduit portion 30b is provided between the leading edge boss 102 and the external cover sleeve 64 (flowing parallel to the bore 12), and further on between the leading edge boss 102 and onto the trailing edge submember 49 of the valve member housing 46. A small amount of hydraulic fluid covers the valve member housing 46 as it exits the secondary fluid conduit portion 30b. The initial fluid conduit portion 30a, the hydraulic reservoir 114 and the secondary fluid conduit portion 30b function as a single fluid conduit 30 between the hydraulic chamber 24 and the valve member 20.

It will be appreciated that the volumes of the internal hydraulic chamber 24 and the hydraulic reservoir 114 are variable and inversely proportional to one another: with the valve member 20 closed (see Fig. 10) the internal hydraulic chamber 24 has a very small if not virtually nil volume, whereas the volume of the hydraulic reservoir 114 is at its greatest. As hydraulic fluid is fed into the hydraulic chamber 24 via the ports 26 at a hydraulic supply pressure, the movement of the hydraulic sleeve 22 towards the trailing edge 36 of the valve 10 causes the volume of the internal hydraulic chamber 24 to increase and accordingly the volume of the hydraulic reservoir 114 to decrease. In this transitionary process, it is only when hydraulic pressure is being applied to the internal hydraulic chamber 24 that there is a pressure within the hydraulic reservoir 114 sufficient to inject hydraulic fluid across the valve member housing 46 and onto the valve member 20. When the valve member 20 is fully closed there is no pressure within the internal hydraulic chamber 24 and therefore no downstream pressure through the initial conduit 30a, the reservoir 114 or the secondary conduit 30b, i.e. the conduit as a whole. Similarly, when the valve member 20 is fully open (see Fig. 11), the volume of the hydraulic reservoir 114 becomes virtually nothing, and the pressure is static between the well pressure and the hydraulic fluid in the conduit 30 as a whole. Thus, it is only when the hydraulic fluid supply is pressurised to cause a transition between the closed and open states of the valve member 20 that hydraulic fluid is injected onto the valve member 20. Moreover, the mechanical linkage 28 is continually bathed in hydraulic fluid, thereby mitigating wear on the parts.

In the present embodiment, it is envisaged that well fluid flowing within the bore 12 will be at a well pressure of approximately 1000 psi (6900 kPa). The hydraulic fluid will be fed into the internal hydraulic chamber 24 at approximately 3000 psi (20700 kPa). As the valve member 20 is turning, the pressure in the hydraulic reservoir 114 will be approximately 2000 psi (13800 kPa). This means that well fluid cannot flow back along the fluid conduit 30 to contaminate the hydraulic fluid supply; there is always a greater hydraulic supply pressure than well pressure, preventing contamination. It is envisaged that a relatively small amount of hydraulic fluid will be injected onto the exterior surface of the valve member, thereby lubricating it. Typically, this will be a quantity of 5ml or less. A main spring housing portion 86 extends towards the trailing edge 36 from the lip 84 and initial cylinder portion 82. A coil spring 88 is provided within the main spring housing portion 86. A spring washer 90 is provided at the leading edge side of the coil spring 88 adjacent the lip 84. The spring washer 90 abuts the trailing edge of the lesser diameter trailing edge portion 74 of the hydraulic chamber piston 70. Thus, the coil spring 88 urges the hydraulic chamber piston 70 towards the leading edge 34 and consequently the valve member 20 into a closed position. The lip 84 acts as a shoulder beyond which the spring washer 90 may not pass (see Fig. 11).

A spring mandrel 92 is provided within the main spring housing portion 86 which together encase the coil spring 88. The spring mandrel 92 is a sleeve which defines part of the internal bore 14.

A locking portion 94 attaches to the main spring housing portion at the trailing edge. The locking portion 94 comprises a typical prior art threaded locking portion 94 and will not be described further, its functioning being well within the knowledge of the skilled addressee.

A tail portion 120 fits onto the trailing edge of the locking portion 94. A tail mandrel portion 122 fits into the locking portion 94.

Fig. 12 depicts a second embodiment valve sub-member 247. The second embodiment valve sub-members are largely identical to the first embodiment shown in Fig. 7, and a similar numbering scheme has been applied with a prefixing “2” to differentiate them. The only significant difference is the addition of fluid apertures 255 through the curved sidewalls 243. These fluid apertures 255 allow hydraulic fluid to pass through them and more readily onto the valve member (not shown).

Fig. 13 depicts a second embodiment mechanical linkage 228 which may be used in place of the yoke type mechanism described above. The second embodiment mechanical linkage 228 is a rack and pinion mechanism. Upper and lower connecting rods 233 are provided which connect to the hydraulic sleeve 222 at their trailing edge and the inner leading edge sleeve 239 at their leading edge. Racks 235 are provided on the connecting rods 233 and a cooperating pinion 231 which attaches to the valve member 220 via an appropriately shaped pinion aperture 229, which in the present embodiment is a squircle shape i.e. a generally square aperture with filleted corners. It will also be understood that other mechanical linkages are able to be used and especially a trunnion mechanism may be in used either in place of the yoke-type mechanism of the first embodiment or the rack and pinion of the second embodiment.