AU2015201953A1 - Improved Valve Apparatus - Google Patents

Abstract

A valve apparatus 30 for a well comprises a blowout preventer valve 31 through which a fluid flowing from the well is able to flow, and a diverter valve 32 operable to divert the fluid flowing from the well to prevent the fluid from flowing through the blowout preventer valve 31 and to actuate the blowout preventer valve 31.

Description

1 IMPROVED VALVE APPARATUS FIELD OF THE INVENTION [0001] The present invention relates generally to valve apparatus for controlling the flow of fluid from a well. [0002] Although the present invention will be described with particular reference to being used to control the flow of crude oil and/or natural gas from a subsea well, it will be appreciated that it is not necessarily limited to this particular use. BACKGROUND ART [0003] A blowout in the context of well drilling is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. [0004] There have recently been a number of significant oil well blowouts. On 21 August 2009 the West atlas oil rig was involved in a blowout that occurred in the Timor Sea off the coast of Western Australia. Another blowout which resulted in the destruction and sinking of the Deepwater Horizon oil rig occurred in the Gulf of Mexico on 20 April 2010. [0005] Both the Timor Sea blowout and the Gulf of Mexico blowout resulted in the uncontrolled release of large quantities of crude oil and natural gas into the surrounding environment. The release of this crude oil and natural gas has been quite harmful to the surrounding environments as well as to the wildlife inhabiting those environments. [0006] When drilling a well, a large specialised valve called a "blowout preventer" or "BOP" is normally used to cope with extreme erratic pressures and uncontrolled flow (formation kick) emanating from a well reservoir, and for preventing well blowouts. In addition to controlling the downhole pressure and the flow of oil and gas, blowout preventers are intended to prevent tubing (e.g. drill pipe and well casing), tools and drilling fluid from being blown out of the wellbore when a blowout threatens. Blowout preventers are critical to the safety of crew, rig, and the environment, and to the monitoring and maintenance of well integrity. Consequently, blowout preventers are intended to be fail-safe devices.

2 [0007] Although blowout preventers are intended to be fail-safe devices, they nevertheless do occasionally fail. If a blowout preventer fails, it can be very difficult to regain control over the flow of oil and/or gas from the well. During the period that control is lost, a large quantity of oil and/or gas from the well may flow into the surrounding environment. [0008] Even if a blowout preventer successfully prevents a blowout from occurring, the sudden increase in pressure in the well that is caused by the operation of the blowout preventer can damage the well and also the geological formation in which the well has been drilled. In some cases, the damage to the well and the formation can be severe enough that oil and/or gas is/are able to escape from the well and flow into the formation. The escaped oil and/or gas may then find its way into the environment through geological fissures and the like. [0009] Our International Patent Publication No. WO 2012/068624 Al, the contents of which are incorporated herein by reference in their entirety, discloses a valve apparatus that can be used to control the flow of oil and gas from a well in the event of a well blowout. The valve apparatus comprises a diverter valve that includes a valve body, and a valve member. The valve body includes a first passage that extends through the valve body, at least one second passage that extends through the valve body and laterally from the first passage. The valve body is connectable to the well so that a fluid flowing from the well is able to flow out of the valve body through the first passage. The valve member is insertable into the first passage and is moveable relative to the valve body by one or more hydraulic cylinders or other suitable lifting means located externally of the first passage so as to thereby control the flow of the fluid from the first passage into each second passage so that the flow of the fluid out of the valve body through each second passage can be controlled. The fluid that flows out of the valve body through each second passage can then be directed to flow into a tanker through pipes or hoses that are connected to each second passage. In this way, the valve apparatus is able to control the flow of fluid from the well and prevent it from escaping into the surrounding environment. [0010] A particular version of the valve apparatus disclosed in WO 2012/068624 Al includes a blowout preventer mounted on the valve member of 3 the diverter valve. The blowout preventer can be closed hydraulically so that the flow of fluid from the well can be completely shutoff or so that fluid from the well can only flow out of the valve body through each second passage thereof. [0011] An issue with this particular version of our earlier valve apparatus is that if the blowout preventer has a hydraulic failure and cannot be closed, the flow of fluid from the well cannot be completely shut off or limited to only flowing out of the diverter valve body through each second passage thereof unless the blowout preventer is fixed or unless some other means is available that can take over the role of the blowout preventer. [0012] It is against this background that the present invention has been developed. SUMMARY OF THE INVENTION [0013] It is an object of the present invention to overcome, or at least ameliorate, one or more of the deficiencies of the prior art mentioned above, or to provide the consumer with a useful or commercial choice. [0014] Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed. [0015] According to a first broad aspect of the present invention, there is provided a valve apparatus for a well, the apparatus comprising a blowout preventer valve through which a fluid flowing from the well is able to flow, and a diverter valve operable to divert the fluid flowing from the well to prevent the fluid from flowing through the blowout preventer valve and to actuate the blowout preventer valve. [0016] Having the diverter valve operable to actuate the blowout preventer valve is advantageous in that it allows the blowout preventer valve to be actuated even in the event that the blowout preventer valve has a hydraulic failure which would ordinarily prevent the blowout preventer valve from being actuated. [0017] Preferably, the diverter valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow to the 4 blowout preventer valve, and at least one outlet connected to the passage so that the fluid flowing through the passage is able to be diverted to flow from the passage and out of the valve body through each outlet instead of to the blowout preventer valve, and a piston moveable along the passage so as to control the flow of the fluid through each outlet and to actuate the blowout preventer valve. [0018] Preferably, the passage of the diverter valve body comprises a bore. [0019] Preferably, the valve apparatus also comprises a hydraulic connector for connecting the apparatus to a riser pipe. [0020] Preferably, the valve body comprises a valve seat for the piston to rest against, and an inlet that extends to the valve seat so that a fluid injected through the inlet is able to clean the valve seat. [0021] Preferably, the valve apparatus also comprises a choke and kill line that is able to communicate with the passage of the valve body. Preferably, the valve apparatus also comprises a control valve that is connected to the choke and kill line. [0022] Preferably, the valve apparatus also comprises a guide structure for aligning the valve apparatus with the well. [0023] In a first preferred embodiment, the blowout preventer valve comprises an annular blowout preventer valve. Preferably, the annular blowout preventer valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow, a packing unit operable to at least partially seal the passage of the annular blowout preventer valve body, a primary piston operable to actuate the packing unit, and a secondary piston operable by the diverter valve piston to operate the main piston. [0024] Preferably, the passage of the annular blowout preventer valve body comprises a bore. [0025] In a second preferred embodiment, the blowout preventer valve comprises a spherical blowout preventer valve. Preferably, the spherical blowout preventer valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow, a packing unit operable to at least 5 partially seal the passage of the spherical blowout preventer valve body, and a piston operable by the diverter valve piston to actuate the packing unit. [0026] Preferably, the passage of the spherical blowout preventer valve body comprises a bore. [0027] Preferably, the valve apparatus also comprises an automatic fail-safe device/system that is able to operate the apparatus in the event of the failure of other systems that are operable to control the valve apparatus. [0028] According to a second broad aspect of the present invention, there is provided a method of operating the valve apparatus according to the first broad aspect of the present invention, the method comprising the steps of: operating the diverter valve of the apparatus to divert a fluid flowing from a well to prevent the fluid from flowing through the blowout preventer valve of the apparatus; and actuating the blowout preventer valve with the diverter valve. [0029] According to a third broad aspect of the present invention, there is provided a blowout preventer valve for a well, the blowout preventer valve comprising a valve body including a passage through which a fluid flowing from the well is able to flow, a packing unit operable to at least partially seal the passage, and a piston operable by a diverter valve to actuate the packing unit. [0030] According to a fourth broad aspect of the present invention, there is provided a diverter valve for a well, the diverter valve comprising a valve body including a passage through which a fluid flowing from the well is able to flow, and at least one outlet connected to the passage so that the fluid flowing through the passage is able to be diverted to flow from the passage and out of the valve body through each outlet, and a piston moveable along the passage so as to control the flow of the fluid through each outlet and to actuate a blowout preventer valve. BRIEF DESCRIPTION OF THE DRAWINGS [0031] In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: 6 Figure 1 is an exploded cross-sectional perspective view of a first valve apparatus; Figure 2 is a diagrammatic cross-sectional view of the assembled first valve apparatus; Figure 3 is an exploded view of a second valve apparatus; Figure 4 is a diagrammatic cross-sectional view of the assembled second valve apparatus when a H4 connector or latch locking system is used to secure the spherical blowout preventer valve to the diverter valve, and when the removable head and valve body of the spherical blowout preventer valve are secured together with bolts; Figure 5 is a diagrammatic cross-sectional view of the assembled second valve apparatus when H4 connectors or latch locking systems are used to secure the spherical blowout preventer valve to the diverter valve, and to secure the removable head to the valve body of the spherical blowout preventer valve; Figure 6 is a diagrammatic cross-sectional view of a third valve apparatus; Figure 7 depicts a fourth valve apparatus; and Figure 8 depicts a fifth valve apparatus connected to a riser pipe and a wellhead. DESCRIPTION OF EMBODIMENTS [0032] In the drawings, like features have been referenced with like reference numbers. [0033] Referring to figures 1 and 2, there is depicted a first valve apparatus 30 for a subsea hydrocarbon well (not depicted) such as a crude oil and/or natural gas well. Valve apparatus 30 includes a blowout preventer valve 31 through which a fluid flowing from the well is able to flow. Valve apparatus 30 also includes a diverter valve 32 operable to divert the fluid from the well to prevent the fluid from flowing through the blowout preventer valve 31 and to actuate the blowout preventer valve 31. [0034] Diverter valve 32 includes a valve body 35 that includes a passage in the form of a bore 36 through which the fluid flowing from the well is able to flow to the blowout preventer valve 31. Valve body 35 also includes a plurality of 7 outlets 37 connected to the bore 36 by a plurality of passages 38 so that the fluid flowing through the bore 36 is able to be diverted to flow from the bore 36 and out of the valve body 35 through each outlet 37 instead of to the blowout preventer valve 31. [0035] Diverter valve 32 also includes a hollow piston 39 that is received by the bore 36 of the valve body 35. Piston 39 is slidingly moveable along the bore 36 of the valve body 35 so as to control the flow of the fluid through each outlet 37 and to actuate the blowout preventer valve 31. [0036] A lower end 40 of the valve body 35 is machined or otherwise configured so that it is able to be connected to the well either directly or indirectly. In the case where the lower end 40 is to be connected to the well indirectly, the lower end 40 may be machined or otherwise configured to suit a range of third party connectors for securing blind shears, or the lower ram assembly of grab rams to the lower end 40. The valve body 35 may be secured to the well such that the bore 36 is aligned with a bore of the well. [0037] The valve body 35 includes a valve seat 41, and a lower end 42 of a lower section 43 of the piston 39 is configured so that the lower end 42 is able to sealingly engage with the valve seat 41. [0038] Blowout preventer valve 31 comprises an annular blowout preventer valve 50. Annular blowout preventer valve 50 comprises an annular valve body 51 that includes a passage in the form of a bore 52 through which the fluid flowing from the well is able to flow. A lower section 53 of the valve body 51 is inserted into the bore 36 of the diverter valve body 35 such that the valve body 51 and the piston 39 overlap with each other as shown in figure 2. The diverter valve body 35 and the blowout preventer valve body 51 are secured together by a H4 connector or latch locking system (not depicted) such that the joint between the valve bodies 35, 51 is sealed. [0039] A piston chamber 54 which receives the piston 39 is defined by the valve bodies 35, 51. The piston chamber 54 is sealed by a plurality of steel 0 rings (not depicted) that are located in a plurality of grooves 55 in the valve body 35, and by a plurality of O-ring seals that are located in a plurality of grooves 57 in the valve body 51. The piston chamber 54 is divided into separate sealed 8 sections (i.e. an upper section and a lower section) by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 56 in the piston 39. [0040] The maximum length of travel of the piston 39 in the piston chamber 54 is the same as the length of the lower section 43 of the piston 39. [0041] A hollow secondary piston 58 is received by the bore 52 such that the piston 58 is slidingly moveable along the bore 52 and such that a lower section 59 of the secondary piston 58 overlaps with the piston 39 as shown. A piston chamber 60 is defined by the piston 58 and the valve body 51. The piston chamber 60 is sealed by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 61 in the piston 58, a plurality of grooves 62 in the piston 39, and in a plurality of grooves 63 in the piston 58. [0042] The maximum length of travel of the piston 39 in the piston chamber 60 is roughly 75% of the maximum length of travel of the piston 39 in the piston chamber 54. Consequently, the diverter valve 32 can only be opened by roughly 75% before the piston 39 reaches the maximum extent of its travel within the piston chamber 60. [0043] An annular primary piston 64 is received by the bore 52 such that the piston 64 is slidingly moveable along the bore 52. A plurality of rods 65 are each fixed at one end to the piston 64 such that the rods 65 are circumferentially spaced around the piston 64 and extend upwardly therefrom. Each rod 65 extends through a respective hole 66 in an annular guide member 67 that is received in the bore 52. Also, the secondary piston 58 is slidingly received by an annular groove 68 in the guide member 67. [0044] A piston chamber 69 is defined by the valve body 51 and the guide member 67. The piston chamber 68 is sealed by the plurality of O-ring seals located in the grooves 63 in the secondary piston 58, and by a plurality of O-ring seals (not depicted) located in grooves 70 in the guide member 67. The piston chamber 69 is divided into separate sealed sections by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 71 in the secondary piston 58, and in a plurality of grooves 72 in the primary piston 64. [0045] The maximum length of travel of the piston 39 in the piston chamber 60 is the same as the maximum length of travel of the piston 64 in the piston 9 chamber 69. Also the maximum length of travel of the piston 58 before it contacts the guide member 67 is the same as the maximum length of travel of the piston 58 in the piston chamber 69. [0046] A piston chamber 73 is defined by the guide member 67. The piston chamber 73 is sealed by some of the plurality of O-ring seals located in the grooves 70 of the guide member 67, an O-ring seal (not depicted) that is located in a groove 74 in the guide member 67, and by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 75 in the secondary piston 58. [0047] An upper end of each rod 65 is secured to an annular jaw member 76 that is received in the bore 52 such that the jaw member 76 is slidingly moveable along the bore 52. Jaw member 76 includes an inclined wedge face 77 on which rests an annular packing unit 78. Packing unit 78 comprises an annular rubber or elastomeric body 79 that has metal inserts (not depicted), and an annular seal 80 that is received by the body 79 and that rests on the guide member 67. A wear plate (not depicted) is located between the packing unit 78 and the guide member 67. [0048] A removable head 81 is received by the bore 52 and is secured to the valve body 51 with a H4 connector or latch locking system (not depicted) such that the joint between the valve body 51 and the head 81 is sealed. Removable head 81 includes a wedge face 82 which rests against the packing unit 78. A wear plate (not depicted) is located between the packing unit 78 and the head 81. [0049] A plurality of O-ring seals (not depicted) that are located in grooves 83 in the annular jaw 76 form a seal between the annular jaw 76 and the head 81. A plurality of O-ring seals (not depicted) that are located in grooves 84 in the valve body 51 form a seal between the valve body 51 and the head 81. [0050] An upper end 85 of the head 81 is machined to suit a range of connectors for securing another blowout preventer valve (e.g. an annular blowout preventer valve) to the head 81, or for securing other equipment such as blind shears, a grab ram, flexi joint, or a lower marine riser package to the head 81. [0051] The valve apparatus 30 is assembled by firstly inserting the piston 39 into the bore 36 of the valve body 35. The valve body 51 is then inserted into the 10 bore 36 of the valve body 35 so that the piston 39 is captured between the valve bodies 35, 51 and so as to form the piston chamber 54. The valve bodies 35, 51 are then secured to each other in the manner described earlier. The secondary piston 58 is inserted into the bore 52 of the valve body 51 so as to form the piston chamber 60. [0052] The rods 65 are fixed to the primary piston 64 and are inserted through the holes 66 in the annular guide member 67. The rods 65 are then fixed to the annular jaw 76. The assembly comprising the primary piston 64, rods 65, and guide member 67 is then inserted into the bore 52 of the valve body 51 so that the primary piston 64 rests on the secondary piston 58, and so that the secondary piston 58 is inserted into the annular groove 68 in the guide member 67. [0053] After inserting one of the wear plates into the bore 52 so that the wear plate rests on top of the guide member 67, the annular packing unit 78 which comprises the body 79 and the annular seal 80 inserted into the body 79 is then inserted into the bore 52 such that the packing unit 78 rests on the wedge face 77 of the annular jaw 76 and on the wear plate. The other wear plate is placed on top of the packing unit 78. Finally, the head 81 is inserted into the bore 52 and is secured to the valve body 51 in the manner described earlier. [0054] A drill string may extend through a riser which is connected to the valve apparatus 30 and through the valve apparatus 30 and into the wellbore of the well to which the valve apparatus 30 is secured such that the drill string extends through the bore 36 of the valve body 35 and through the bore 52 of the valve body 51. [0055] In normal use, the piston 39 is in the closed position so that its lower end 42 is sealingly engaged with the valve seat 41 so that fluid flowing from the wellbore into the bore 36 is unable to flow from the bore 36 and through the outlets 37. [0056] If sensors monitoring the well alert well operators to a kick in the well which begins to go out of control and turn into a well blowout, the diverter valve 32 is opened by around 75% so that the fluid (e.g. hydrocarbons) flowing from the well and into the bore 36 is diverted to flow from the bore 36 and out of the 11 valve body 35 through each outlet 37 instead of to the annular blowout preventer valve 50. After passing out of the valve body 35 through the outlets 37, the fluid flows through hoses or pipes that are connected to the outlets 37 and that lead to storage tanks which may be located on a ship or elsewhere so that the fluid is captured and does not pollute the environment. [0057] The diverter valve 32 is opened by pumping hydraulic fluid into a lower section of the piston chamber 54 through a port 90 in the valve body 35, allowing hydraulic fluid in an upper section of the piston chamber 54 to be vented through a port 91 in the valve body 35, and by allowing hydraulic fluid in the piston chamber 60 to be vented through a port 92 in the valve body 51. [0058] Diverting the fluid to flow through the outlets 37 instead of to and through the annular blowout preventer valve 50 and up to the rig or intervention vessel relieves the flow of fluid going through the riser to the rig or intervention vessel. This loss of pressure in the riser that is connected to the valve apparatus 30 and that leads to the rig or intervention vessel will allow the drillers on the rig or intervention vessel to regain control over the drill string so that it can be removed from the well. [0059] Once the drill string has been removed from the well so that the drill string does not extend past the packing unit 78, the process of shutting down the well can commence. The well is shut down by pumping hydraulic fluid into the section of the piston chamber 69 between the secondary piston 58 and the primary piston 64 through a port in the valve body 51 and by allowing hydraulic fluid in the section of the chamber 69 located above the piston 64 to be vented through a port 94 in the valve body 51. This moves the piston 64 and, hence, the rods 65, and the annular jaw 76 upwardly along the bore 52. As the jaw 76 moves upward it translates force to packing unit 78 through wedge face 77. The force translated to packing unit 78 from wedge face 77 is directed upward toward the head 81, and inward toward a central axis of the wellbore which is aligned with the bore 52 of the valve body 51 and the bore 36 of the valve body 35. Because the packing unit 78 is retained against the head 81 of the annular blowout preventer 50, the packing unit 78 does not displace upward from the force translated to the packing unit 78 from the annular jaw 76. However, the packing unit 78 does displace inward from the translated force, which 12 compresses the packing unit 78 toward the central axis of the wellbore. In the event that a drill pipe is located within the bore 52, with sufficient radial compression, the packing unit 78 will seal about the drill pipe into a closed position. [0060] In the event that a drill pipe is not present in the bore 52, the packing unit 78, with sufficient radial compression, will completely seal the bore 52 so that fluid flowing from the well is unable to flow through/past the annular blowout preventer 50. In this situation, all of the fluid will be diverted to flow from the bore 36 and out of the valve body 35 through the outlets 37. [0061] Once the packing unit 78 is in the closed position, the ports 93 and 94 can be blocked so as to prevent the piston 64 and, hence, the rods 65 and annular jaw 76 from moving downwardly. [0062] Once the packing unit 78 is in the closed position, the diverter valve 32 can be closed by pumping hydraulic fluid into the upper section of the piston chamber 54 through the port 91, pumping hydraulic fluid into the piston chamber 60 through the port 92, and by allowing hydraulic fluid in the lower section of the piston chamber 54 to be vented out through the port 90. The diverter valve 32 is closed once the lower end 42 of the piston 39 sealingly engages with the valve seat 41 so that fluid from the well is no longer able to flow from the bore 36 and out of the valve body 35 through the outlets 37. [0063] Once the diverter valve 32 is closed along with the annular blowout preventer 50 (by virtue of the packing unit 78 being in the closed position), the well is shutdown so that fluid can no longer flow out of it. [0064] The annular blowout preventer 50 can be opened by opening the packing unit 78. This can be accomplished by pumping hydraulic fluid into the section of the piston chamber 69 which is located above the piston 64 through the port 94, and by allowing hydraulic fluid in the section of the chamber 69 between the pistons 58 and 64 to be vented out through the port 93. [0065] In the event of the annular blowout preventer 50 having a hydraulic failure which prevents the packing unit 78 from being moved to the closed position by pumping hydraulic fluid in through the port 93 and venting hydraulic fluid out through the port 94 as described above, the packing unit 78 can be 13 moved to the closed position by the diverter valve 32 so that the diverter valve 32 thereby actuates the annular blowout preventer 50. This can be accomplished by pumping more hydraulic fluid into the piston chamber 54 through the port 90 so that the piston 39 is moved further upwards towards the piston 58. As the piston 39 moves further towards the piston 58, hydraulic fluid in the piston chamber 60 is vented therefrom through the port 92. Once the piston 39 reaches the piston 58, a timing switch (not depicted) locks ports 93 and 94 so that hydraulic fluid cannot flow out of the piston chamber 69 through the port 93, or in to the piston chamber 69 through the port 94. Also, hydraulic fluid is pumped into the lowermost section of the piston chamber 69 through a port 95 in the valve body 51. The hydraulic fluid that is pumped in to the piston chamber 69 through the port 95 pushes upwardly on the secondary piston 58 and assists the piston 39 to move the piston 58 upwardly along the bore 52. As the secondary piston 58 is moved upwardly along the bore 52, it pushes upwardly on the primary piston 64 which in turn pushes upwardly on the rods 65 and the annular jaw 76. This upward movement of the annular jaw 76 exerts a force on the packing unit 78 which causes it to move to the closed position in the manner previously described. Hydraulic fluid in the piston chamber 73 is vented through a port 96 in the valve body 51 as the piston 58 moves upwards. The diverter valve 32 is fully open after the piston 39 has moved the piston upwardly 58 to such an extent that the annular blowout preventer 50 is closed. [0066] Once the secondary piston 58 has been moved upwardly to the maximum possible extent so that the packing unit 78 is in the closed position, hydraulic fluid can then be pumped into the upper section of the piston chamber 54 through the port 91 and into the piston chamber 60 through the port 92, and hydraulic fluid can be vented from the lower section of the piston chamber 54 through the port 90 so that the piston 39 is moved to the closed position where its lower end 42 sealingly engages with the valve seat 41. Once the piston 39 has been moved to the closed position and fluid from the well no longer flows from the bore 36 and out through the outlets 37, ports 92 and 95 are blocked to prevent downward movement of the secondary piston 58 along the bore 52. Blocking port 92 also prevents the piston 43 from moving upwardly along the valve body 35. Thus, the piston 39 and the piston 58 are effectively locked apart 14 from each other so that the diverter valve 32 and the annular blowout preventer 50 remain closed. [0067] The primary piston 64, secondary piston 58, and the piston 39 each have their own independent hydraulic power supply for operating them. Consequently, primary piston 64 is able to be operated independently of secondary piston 58, and piston 39 is able to be operated independently of both primary piston 64 and secondary piston 58. If hydraulic pressure is lost by secondary piston 58 through port 93, as an override for this problem it would be possible to operate piston 58 by applying pressure through port 95 to apply force to the lower part of the piston 58 so that the piston 58 is lifted. Secondary piston 58 can also be moved upwardly by applying positive pressure to port 90 so that the piston 39 moves upwardly, engages with piston 58, and forces piston 58 upward. [0068] A second valve apparatus 100 is depicted in figures 3 and 4. The valve apparatus 100 is more or less identical to the first valve apparatus 30 except that the blowout preventer valve 31 of the second valve apparatus 100 comprises a spherical blowout preventer valve 101. [0069] Diverter valve 32 of the second valve apparatus 100 is more or less identical to the diverter valve 32 of the first valve apparatus 30 and will therefore not be described any further here. [0070] The spherical blowout preventer valve 101 comprises an annular valve body 102 that includes a passage in the form of a bore 103 through which the fluid flowing from the well is able to flow. A lower section 104 of the valve body 102 is inserted into the bore 36 of the diverter valve body 35 such that the valve body 102 and the piston 39 overlap with each other as shown in figure 4. The diverter valve body 35 and the blowout preventer valve body 102 are secured together by a H4 connector or a latch locking system, a portion 105 of which is depicted in figure 4. The valve bodies 35, 102 are secured together such that the joint between them is sealed. [0071] A piston chamber 106 is defined by the valve bodies 35, 102. The piston chamber 106 is sealed by the plurality of O-ring seals (not depicted) that are located in the grooves 55 in the valve body 35, and by a plurality of 0-ring 15 seals (not depicted) that are located in a plurality of grooves 107 in the valve body 102. The piston chamber 106 is divided into separate sealed sections by the plurality of O-ring seals (not depicted) that are located in the plurality of grooves 56 in the piston 39. [0072] The maximum length of travel of the piston 39 in the piston chamber 106 is the same as the length of the lower section 47 of the piston 39. [0073] A hollow piston 108 is received by the bore 103 such that the piston 108 is slidingly moveable along the bore 103 and such that a lower section 109 of the piston 108 overlaps with the piston 39 as shown. A piston chamber 110 is defined by the valve body 102. The piston chamber 110 is sealed by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 111 and 112 in the piston 108, and by the plurality of O-ring seals (not depicted) in the plurality of grooves 62 in the piston 39. [0074] The maximum length of travel of the piston 39 in the piston chamber 110 is roughly 75% of the maximum length of travel of the piston 39 in the piston chamber 106. Consequently, the diverter valve 32 can only be opened by roughly 75% before the piston 39 reaches the maximum extent of its travel within the piston chamber 110. [0075] A seal ring 113 is inserted into the bore 103 such that it extends around the piston 108. The seal ring 113 is secured to a removable head 114 that includes a curved, spherical inner surface 115. A packing unit 116 is disposed between the piston 108 and the head 114. The head 114 is secured to the valve body 102 by a plurality of bolts 117. A wear plate (not depicted) is located between the head 114 and the packing unit 116, and another wear plate (not depicted) is located between the piston 108 and the packing unit 116. [0076] An upper end 118 of the head 114 is machined to suit a range of connectors for securing another blowout preventer valve (e.g. an annular blowout preventer valve) to the head 114, or for securing other equipment such as blind shears, a grab ram, flexi joint, or lower marine riser package to the head 114. [0077] The packing unit 116 includes a curved, rubber or elastomeric annular body 119, and a plurality of curved metal inserts (not depicted) corresponding to the curved, spherical inner surface 115 of the head 114. The metal inserts are 16 disposed within the annular body 119 in a generally circular fashion and spaced apart in radial planes extending from a central axis of the bore 103. [0078] The piston 108 resides in a piston chamber 120 which is sealed by the plurality of O-ring seals located in the grooves 112 in the piston 108, and by a plurality of O-ring seals (not depicted) that are located in grooves 121 in the seal ring 113. The seal ring 113 and the O-rings located in the grooves 121 seal the chamber 120 off from the packing unit 116. The piston chamber 120 is divided into separate sealed sections by a plurality of O-ring seals (not depicted) that are located in a plurality of grooves 122 in the piston 108. [0079] The piston 108 reaches its maximum extent of upward travel in the piston chamber 120 when the piston 39 reaches its maximum extent of upward travel in the piston chamber 106. [0080] The valve apparatus 100 is assembled by firstly inserting the piston 39 into the bore 36 of the valve body 35. The valve body 102 is then inserted into the bore 36 of the valve body 35 so that the piston 39 is captured between the valve bodies 35, 102 as so as to form the piston chamber 106. The valve bodies 35, 102 are then secured to each other in the manner described earlier. The piston 108 is inserted into the bore 103 of the valve body 102 so as to form the piston chamber 110. [0081] The seal ring 113 is inserted into the bore 103 of the valve body 102 such that it extends around the outside of the piston 108 and sealingly engages with the piston 108. One of the wear plates is placed on top of the piston 108, and the packing unit 116 is then placed on top of the wear plate. The other wear plate is placed on top of the packing unit 116, and then the head 114 is fitted over the packing unit 116 and is secured to the valve body 102 with the bolts 117. [0082] A drill string may extend through a riser which is connected to the valve apparatus 100 and through the valve apparatus 100 and into the wellbore of the well to which the valve apparatus 100 is secured such that the drill string extends through the bore 36 of the valve body 35 and through the bore 103 of the valve body 102.

17 [0083] In normal use, the piston 39 is in the closed position so that its lower end 42 is sealing engaged with the valve seat 41 so that fluid flowing from the wellbore into the bore 36 is unable to flow from the bore 36 and through the outlets 37. [0084] If sensors monitoring the well alert well operators to a kick in the well which begins to go out of control and turn into a well blowout, the diverter valve 32 is opened by around 75% so that the fluid (e.g. hydrocarbons) flowing from the well and into the bore 36 is diverted to flow from the bore 36 and out of the valve body 35 through each outlet 37 instead of to the spherical blowout preventer valve 101. After passing out of the valve body 35 through the outlets 37, the fluid flows through hoses or pipes that are connected to the outlets 37 and that lead to storage tanks which may be located on a ship or elsewhere so that the fluid is captured and does not pollute the environment. [0085] The diverter valve 32 is opened by pumping hydraulic fluid into a lower section of the piston chamber 106 through the port 90 in the valve body 35, allowing hydraulic fluid in an upper section of the piston chamber 106 to be vented through the port 91 in the valve body 35, and by allowing hydraulic fluid in the piston chamber 110 to be vented through a port 123 in the valve body 102. [0086] Diverting the fluid to flow through the outlets 42 instead of to and through the spherical blowout preventer valve 101 and up to the rig or intervention vessel relieves the flow of fluid going through the riser to the rig or intervention vessel. This loss of pressure in the riser that is connected to the valve apparatus 100 and that leads to the rig or intervention vessel will allow the drillers on the rig or intervention vessel to regain control over the drill string so that it can be removed from the well. [0087] Once the drill string has been removed from the well so that the drill string does not extend past the packing unit 116, the process of shutting down the well can commence. The well is shut down by pumping hydraulic fluid into the lower section of the piston chamber 120 through port 125 in the valve body 102, and by allowing hydraulic fluid in the upper section of the chamber 120 to be vented through a port 126 in the valve body 102. This moves the piston 108 upwardly along the bore 103. As the piston 108 moves upward it translates force to packing unit 116. The force translated to the packing unit 116 from the piston 18 108 is directed upward toward the head 114. Because the packing unit 116 is retained against the curved, spherical inner surface 115 of the head 114, the packing unit 116 displaces upward and inwardly, which compresses the packing unit 116 toward the central axis of the wellbore. In the event that a drill pipe is located within the bore 103, with sufficient radial compression, the packing unit 116 will seal about the drill pipe into a closed position. [0088] In the event that a drill pipe is not present in the bore 103, the packing unit 116, with sufficient radial compression, will completely seal the bore 103 so that fluid from the well is unable to flow through/past the spherical blowout preventer 101. In this situation, all of the fluid will be diverted to flow from the bore 36 and out of the valve body 35 through the outlets 37. [0089] Once the packing unit 116 is in the closed position, the ports 124, 125, 126 can be blocked so as to prevent the piston 108 from moving downwardly. [0090] Once the packing unit 116 is in the closed position, the diverter valve 32 can be closed by pumping hydraulic fluid into the upper section of the piston chamber 106 through the port 91, pumping hydraulic fluid into the piston chamber 110 through the port 123, and by allowing hydraulic fluid in the lower section of the piston chamber 106 to be vented out through the port 90. The diverter valve 32 is closed once the lower end 42 of the piston 39 sealingly engages with the valve seat 41 so that fluid from the well is no longer able to flow from the bore 36 and out of the valve body 35 through the outlets 37. [0091] Once the diverter valve 32 is closed along with the spherical blowout preventer 101 (by virtue of the packing unit 116 being in the closed position), the well is shutdown so that fluid can no longer flow out of it. [0092] The spherical blowout preventer can be opened by opening the packing unit 116. This can be accomplished by pumping hydraulic fluid into the upper section of the piston chamber 120 through the port 126, and by allowing hydraulic fluid in the lower section of the chamber 120 to be vented out through the ports 124, 125. [0093] In the event of the spherical blowout preventer 101 having a hydraulic failure which prevents the packing unit 116 from being moved to the closed 19 position by pumping the hydraulic fluid into the piston chamber 120 through the port 125 and by venting hydraulic fluid out of the chamber 120 through the port 126 as described above, the packing unit 116 can be moved to the closed position by the diverter valve 32 so that the diverter valve 32 thereby actuates the spherical blowout preventer 101. This can be accomplished by pumping more hydraulic fluid into the piston chamber 106 through the port 90 so that the piston 39 is moved further upwards towards the piston 108. As the piston 39 moves further towards the piston 108, hydraulic fluid in the piston chamber 110 is vented therefrom through the port 123. A sensor (not depicted) senses when the piston 39 reaches the piston 108, and this will trigger the pumping of hydraulic fluid into the lower section of the piston chamber 120 through the ports 124, 125 which will assist the piston 39 to move the piston 108 upwardly and thereby move the packing unit 116 to the closed position. Once the packing unit 116 is closed, the piston 39 is in the fully open position so that the diverter valve 32 is fully open. [0094] Once the packing unit 116 is in the closed position, the hydraulic ports 125 and 126 are locked to prevent the piston 108 from moving downwards and causing the packing unit 116 to open. [0095] The diverter valve 32 remains in the fully open position for as long as is required for the well to remain open so that fluid flowing from the well is diverted to flow from the bore 36 and out of the valve body 35 through the outlets 37. [0096] To close the well down completely, hydraulic fluid is pumped in to the piston chamber 110 through ports 123, 124 so that the resultant pressure in the chamber 110 pushes down on the top of the piston 39. Even pressure can be supplied to ports 123, 124 through a splitter or tee piece (not depicted) connected to those ports 123, 124. At the same time, hydraulic fluid is pumped into the upper section of the piston chamber 106 through the port 91 so as to assist in moving the piston 43 downwards. The piston 39 is moved downwards until the lower end 42 of the piston 39 sealingly engages with the valve seat 41 [0097] Once the well has been shut down completely, a survey can be conducted of the seabed for hydrocarbons. If the survey determines that hydrocarbons are leaking through the seabed from the shutdown well, the 20 diverter valve 32 can be reopened to reduce the pressure inside the well. If the survey determines that no hydrocarbons are leaking through the seabed from the shutdown well, the diverter valve 32 can remain shut. [0098] If positive hydraulic pressure is applied to the piston 108 via the ports 123, 124 when the packing unit 116 is closed and when the diverter valve 32 is closed, this hydraulic pressure will also act to keep the piston 39 closed. This consequently forms a double hydraulic locking system which provides added safety. [0099] Each piston 39, 108 is operated by its own independent hydraulic power supply so that the pistons 39, 108 can be operated independently of each other. [00100] Figure 5 depicts the second valve apparatus 100 when the head 114 is secured to the valve body 102 by a latch locking system 127. It also depicts a latch locking system 128 that secures the valve bodies 35, 102 together and that includes the portion 105 depicted in figure 4. [00101] Figure 6 depicts a third valve apparatus 150 which is identical to the second valve apparatus 100 except that it also includes an automatic fail-safe device/system 151 that is able to operate the apparatus 150 in the event of the failure of other systems that are operable to control the apparatus 150. The automatic fail-safe device/system 151 includes a coil spring 152 that extends around the piston 39 and that is located on a lifting side of the piston 39 between the piston 39 and the diverter valve body 35. The coil spring 152 is compressed when the diverter valve 32 of the apparatus 150 is closed. If a problem arises and power or a signal is lost to the stack, a solenoid-operated valve (not depicted) of the apparatus 150 will open so that hydraulic pressure on the opposite side of the piston 39 to the spring 152 will be released so as to allow the spring 152 to lift the piston 39 and open the diverter valve 32. Once the diverter valve 32 is opened the diverter valve 32 is able to divert the flow of fluid in the usual manner. [00102] Figure 7 depicts a fourth valve apparatus 160 which is similar to both the second valve apparatus 100 and the third valve apparatus 150. Apparatus 160 includes a hydraulic connector 161 for connecting the apparatus 160 to a 21 riser pipe (not shown). The hydraulic connector 161 extends from a head 114 of the blowout preventer valve 31. In addition, the valve body 35 of the diverter valve 32 of the apparatus 160 includes an inlet 162 that extends to the valve seat 41 of the apparatus 160. The inlet 162 is part of a flushing or cleaning system that is operable to clean the valve seat 41 to ensure that a lower end of the piston 39 of the apparatus 160 is able to properly seal against the valve seat 41 when the diverter valve 32 of the apparatus 160 is closed. The flushing system functions by injecting a suitable cleaning fluid through the inlet 162 so that the fluid cleans the valve seat 41. [00103] Figure 8 depicts a fifth valve apparatus 170 which is similar to the valve apparatus 160. The apparatus 170 is shown connected to a riser pipe 171 and a wellhead 172 which is in turn connected to a well 173. The apparatus 170 includes a plurality of choke and kill lines 174 that are able to communicate with the bore 36 of the valve body 35. Each line 174 is able to be used to supply kill mud to the well 173, measure the pressure in the well 173 at a location which is below the blowout preventer valve 31 of the apparatus 170, periodically flush or clean the interior of the apparatus 170, and/or quench gas which may emanate from the well 173. A respective control valve 175 which is connected in series with each line 174 is operable to open or close the line 174. [00104] Rather than having choke and kill lines 174 to supply kill mud to the well 173, a bell nipple (not depicted) and flow line (not depicted) may be connected to the blowout preventer valve 31 of the apparatus 170 so that kill mud can be supplied to the well 173 via the bell nipple and the flow line connected thereto. [00105] Also shown in figure 8 is a plurality of flow lines 176 which are connected to the diverter valve 32 of the apparatus 170 so that, when the diverter valve 32 is open, fluid will flow from the well 173, out of the diverter valve 32, and through the flow lines 176. The flow lines 176 are connected to storage tanks (not depicted) which may be located on a barge or other vessel floating above the well 173 so that the fluid that flows through the lines 176 can be stored in the tanks. In the event of a loss of electrical power and/or hydraulic supply to the apparatus 170, the diverter valve 32 of the apparatus 170 will open so that fluid will flow from the well 173 and through the flow lines 176.

22 [00106] Apparatus 170 is connected to the wellhead 172 by a wellhead connector 177 that is secured to the wellhead 172 and to a lower end of the valve body 35 of the apparatus 170. Apparatus 170 is connected to the riser pipe 171 by a sleeve 178 that extends over and is secured to the hydraulic connector 161 of the apparatus 170. The sleeve 178 is also secured to a flexi joint 170 which is in turn secured to the riser pipe 171. [00107] Apparatus 170 also includes a guide structure 180 for assisting in properly aligning the apparatus 170 with the well 173. The guide structure 180 comprises a lower structure 181 secured relative to the wellhead 172, and an upper structure 182 secured relative to the valve body 35 of the apparatus 170. The lower structure 181 includes a plurality of guide posts 183 that are each received by a respective hollow guide post 184 of the upper structure 182. A plurality of support members 85 secure the posts 184 to the wellhead 172. [00108] The valve apparatus 30, 100, 150, and 160 are each configurable as work through apparatus so that drill strings, wire lines, or other equipment are able to be inserted through them and the bore of the well to which the apparatus are connected so that work can be carried out through the bore while the apparatus is connected to the well. [00109] It will be appreciated by those skilled in the art of variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. [00110] Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. [00111] Throughout the specification and claims, unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms. [00112] It will be clearly understood that, if a prior art publication is referred to herein, that reference does not constitute an admission that the publication forms 23 part of the common general knowledge in the art in Australia or in any other country.

Claims (22)

1. A valve apparatus for a well, the apparatus comprising a blowout preventer valve through which a fluid flowing from the well is able to flow, and a diverter valve operable to divert the fluid flowing from the well to prevent the fluid from flowing through the blowout preventer valve and to actuate the blowout preventer valve.

2. The valve apparatus defined by claim 1, wherein the diverter valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow to the blowout preventer valve, and at least one outlet connected to the passage so that the fluid flowing through the passage is able to be diverted to flow from the passage and out of the valve body through each outlet instead of to the blowout preventer valve, and a piston moveable along the passage so as to control the flow of the fluid through each outlet and to actuate the blowout preventer valve.

3. The valve apparatus defined by claim 2, wherein the passage of the diverter valve body comprises a bore.

4. The valve apparatus defined by any one of the preceding claims, wherein the valve apparatus also comprises a hydraulic connector for connecting the apparatus to a riser pipe.

5. The valve apparatus defined by any one of claims 2 to 4, wherein the valve body comprises a valve seat for the piston to rest against, and an inlet that extends to the valve seat so that a fluid injected through the inlet is able to clean the valve seat.

6. The valve apparatus defined by any one of claims 2 to 5, wherein the valve apparatus also comprises a choke and kill line that is able to communicate with the passage of the valve body.

7. The valve apparatus defined by claim 6, wherein the valve apparatus also comprises a control valve that is connected to the choke and kill line.

8. The valve apparatus defined by any one of the preceding claims, wherein the valve apparatus also comprises a guide structure for aligning the valve apparatus with the well. 25

9. The valve apparatus defined by claim 2, wherein the blowout preventer valve comprises an annular blowout preventer valve.

10. The valve apparatus defined by claim 9, wherein the annular blowout preventer valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow, a packing unit operable to at least partially seal the passage of the annular blowout preventer valve body, a primary piston operable to actuate the packing unit, and a secondary piston operable by the diverter valve piston to operate the main piston.

11. The valve apparatus defined by claim 10, wherein the passage of the annular blowout preventer valve body comprises a bore.

12. The valve apparatus defined by claim 2, wherein the blowout preventer valve comprises a spherical blowout preventer valve.

13. The valve apparatus defined by claim 12, wherein the spherical blowout preventer valve comprises a valve body including a passage through which the fluid flowing from the well is able to flow, a packing unit operable to at least partially seal the passage of the spherical blowout preventer valve body, and a piston operable by the diverter valve piston to actuate the packing unit.

14. The valve apparatus defined by claim 13, wherein the passage of the spherical blowout preventer valve body comprises a bore.

15. The valve apparatus defined by any one of the preceding claims, wherein the valve apparatus also comprises an automatic fail-safe device/system that is able to operate the apparatus in the event of the failure of other systems that are operable to control the valve apparatus.

16. A method of operating the valve apparatus according to any one of the preceding claims, the method comprising the steps of: operating the diverter valve of the apparatus to divert a fluid flowing from a well to prevent the fluid from flowing through the blowout preventer valve of the apparatus; and actuating the blowout preventer valve with the diverter valve.

17. A blowout preventer valve for a well, the blowout preventer valve comprising a valve body including a passage through which a fluid flowing from 26 the well is able to flow, a packing unit operable to at least partially seal the passage, and a piston operable by a diverter valve to actuate the packing unit.

18. A diverter valve for a well, the diverter valve comprising a valve body including a passage through which a fluid flowing from the well is able to flow, and at least one outlet connected to the passage so that the fluid flowing through the passage is able to be diverted to flow from the passage and out of the valve body through each outlet, and a piston moveable along the passage so as to control the flow of the fluid through each outlet and to actuate a blowout preventer valve.

19. A valve apparatus substantially as hereinbefore described with reference to the drawings.

20. A method of operating a valve apparatus substantially as hereinbefore described with reference to the drawings.

21. A blowout preventer valve for a well, the blowout preventer valve being substantially as hereinbefore described with reference to the drawings.

22. A diverter valve for a well, the diverter valve being substantially as hereinbefore described with reference to the drawings.