EP1570153B1 - Downhole safety valve for central circulation completion system - Google Patents
Downhole safety valve for central circulation completion system Download PDFInfo
- Publication number
- EP1570153B1 EP1570153B1 EP02793981A EP02793981A EP1570153B1 EP 1570153 B1 EP1570153 B1 EP 1570153B1 EP 02793981 A EP02793981 A EP 02793981A EP 02793981 A EP02793981 A EP 02793981A EP 1570153 B1 EP1570153 B1 EP 1570153B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- gate
- completion system
- bore
- central circulation
- circulation completion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000004519 manufacturing process Methods 0.000 claims description 52
- 239000012530 fluid Substances 0.000 claims description 21
- 230000004888 barrier function Effects 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 6
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 241000191291 Abies alba Species 0.000 description 10
- 238000009434 installation Methods 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- 210000004907 gland Anatomy 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
- E21B33/0355—Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/04—Casing heads; Suspending casings or tubings in well heads
Definitions
- the present invention relates to a downhole safety valve for a central circulation completion system. More particularly, the invention relates to a valve for selectively sealing the annular production bore between the inner tubing string and the outer tubing string in a central circulation completion system.
- a tubing string is suspended from a tubing hanger which is landed in a wellhead housing or in a christmas tree that is installed over the wellhead housing.
- the tubing string extends into the hydrocarbon reservoir and defines a production bore through which well fluids may be produced.
- the tubing string is usually positioned within a casing string which is typically suspended from the wellhead housing.
- the casing string also extends into the reservoir, and the annulus between the tubing string and the casing string defines a service bore through which fluids may be circulated, for example during installation of the completion system.
- Subsea completion systems normally comprise at least one downhole safety valve, such as a surface controlled subsea safety valve (“SCSSV”), which functions to close off the production bore in the event of an emergency.
- SCSSV surface controlled subsea safety valve
- a typical prior art SCSSV comprises a ball valve which is disposed in a cylindrical housing that is mounted within or between successive sections of the tubing string. The ball valve is held in the open position by hydraulic control pressure but is biased toward the closed position by a spring or the like. Accordingly, if a need to close off the production bore arises, the hydraulic pressure is relieved, thus allowing the valve to close.
- the inner tubing string defines a service bore which may be used to circulate fluids during installation and workover operations.
- the annulus between the inner tubing string and a second, outer tubing string defines a production bore through which well fluids are produced.
- central circulation completion systems must also be provided with means to shut off the production bore in the event of an emergency.
- most downhole safety valves are designed to be used with conventional completion systems, wherein well fluids are communicated through the inner tubing string, they generally cannot be used with central circulation completion systems.
- a downhole safety valve for a central circulation completion system comprising an inner tubing string which extends through an outer tubing string and a production bore which is defined between the inner and outer tubing strings.
- the downhole safety valve comprises a generally cylindrical body which includes an outer surface and a through bore that extends generally axially through the body, a mechanism for securing the body to the inner tubing string, and at least one seal for sealing the body to the outer tubing string.
- the body forms a pressure barrier between a first portion of the production bore located below the body and a second portion of the production bore located above the body.
- the downhole safety valve also comprises at least one flow passage which extends through the body and communicates between the first and second portions of the production bore, and at least one closure member which is disposed across the flow passage.
- the inner tubing string comprises at least first and second successive sections
- the securing means comprises first and second threaded receptacles which are aligned with the through bore, and the first and second sections are threadedly connected to corresponding ones of the first and second receptacles.
- the closure member comprises a gate valve which includes a gate that is movable across the flow passage.
- the gate valve includes an actuating mechanism for moving the gate between a closed position in which a hole in the gate is offset from the flow passage and an open position in which the hole is aligned with the flow passage.
- the actuating mechanism comprises a piston which is connected to the gate and which is responsive to a predetermined amount of hydraulic pressure to move the gate from the closed position to the open position.
- the actuating mechanism also comprises a return biasing mechanism which forces the gate from the open position to the closed position in the absence of the predetermined amount of hydraulic pressure.
- the downhole safety valve of the present invention forms an effective pressure barrier for the annulus-shaped production bore of the central circulation completion system.
- the safety valve permits well fluids to flow through the production bore only when a predetermined amount of hydraulic pressure is applied to the actuating mechanism. In the absence of this hydraulic pressure, the return biasing mechanism will close the safety valve and thereby close off the production bore.
- the downhole safety valve of the present invention is shown installed in an exemplary central circulation completion system 12.
- a central circulation completion system can take many forms.
- the central circulation completion system 12 comprises a tubing hanger 14 which is supported in a christmas tree 16 that is installed on a wellhead housing 18.
- the wellhead housing 18 in turn is mounted to the top of a casing string 20 which extends into the hydrocarbon reservoir.
- the casing string 20 may comprise a number of sections of expandable casing 20a, each of which is successively installed using conventional methods.
- a liner section 22 comprising a liner top isolation valve 24 may be installed below the lowermost section of expandable casing 22.
- the exemplary central circulation completion system 12 also comprises an inner tubing string 26, which is suspended from the tubing hanger 14 and extends approximately to the bottom of the casing string 20, and an outer tubing string 28, which is run in through the wellhead housing 18 and expanded into sealing engagement with the liner section 24, the casing string 20 and the wellhead housing in a known manner.
- a production bore 30 is formed between the inner and outer tubing strings 26, 28, and a service bore 32 is formed within the inner tubing string.
- the production bore 30 is used to communicate well fluids from the reservoir to the christmas tree 16 during the production mode of operation, and the service bore 32 is used to circulate fluids between the tubing hanger 14 and the reservoir during installation and well servicing operations.
- a remotely actuatable service isolation valve 34 may be installed in the bottom of the inner tubing string 26 to prevent well fluids from entering the service bore 32 during the production mode of operation.
- the christmas tree 16 comprises a central bore 36 which communicates with the production bore 30. Also, the tubing hanger 14 is sealed within the central bore 36 to form a pressure barrier between the production bore 30 and the environment.
- a tree cap 38 may be installed in the central bore 36 above the tubing hanger 14, and a controls cap 40 comprising a number of remote wet-mate couplers 42 may be removably secured to the tree cap 38 to provide an interface between an external jumper 44 and a number of service and control lines 46 in the tree cap. At least one of these service and control lines 46 is preferably connected with a corresponding service and control conduit 48 in the tubing hanger 14 via a remote subsea matable coupler 50 for reasons which will be described below.
- the christmas tree 16 also includes a number of conduits to effect the production of the well fluids and to facilitate the servicing of the well.
- the christmas tree 16 may comprise a production conduit 52 which communicates with the production bore 30, a production bypass conduit 54 which extends between the production conduit and a portion of the central bore 36 located above the tubing hanger 14, a service conduit 56 which communicates with a service outlet 58 in the tubing hanger 14 that in turn is connected with the service bore 32, a workover conduit 60 which extends between the service conduit and a portion of the central bore located above the tubing hanger or the tree cap 38, and a crossover conduit 62 which is connected between the production conduit and the service conduit.
- the christmas tree 16 typically also includes a number of valves to control the flow of fluids through these conduits.
- the christmas tree 16 may comprise a production master valve 64 and a production wing valve 66 in the production conduit 52, a production bypass valve 68 in the production bypass conduit 54, a service master valve 70 and a service wing valve 72 in the service conduit 56, a workover valve 74 in the workover conduit 60, and a crossover valve 76 in the crossover conduit 62.
- These valves are normally manually or hydraulically actuatable gate valves or the like.
- the safety valve 10 is positioned between the inner and outer tubing strings 26, 28 to control the flow of well fluids through the production bore 30, for example, to seal off the production bore in the event of an emergency.
- the safety valve 10 comprises a generally cylindrical body 78 which has a top surface 80, a bottom surface 82, an outer surface 84 and an annular through bore 86 that extends between the top and bottom surfaces.
- the diameter of the outer surface 84 is sized to be slightly smaller than the diameter of the outer tubing string 28, and the diameter of the through bore 86 is preferably selected to be approximately the same as the diameter of the inner tubing string 26. In this manner, the body 78 will substantially fill the annular void between the inner and outer tubing strings 26, 28.
- the safety valve 10 is deployed with the inner tubing string 26 and is therefore secured and sealed to the inner tubing string prior to being lowered into the production bore 30.
- successive sections of the inner tubing string 26 may be threaded into upper and lower threaded receptacles 88 and 90 which are formed in the through bore 86.
- the body 78 may be secured to the inner tubing string 26 using one or more conventional mechanical fasteners (not shown).
- one or more conventional seals may be provided to seal the body 78 to the inner tubing string.
- the safety valve 10 also includes suitable means to seal the body 78 to the outer tubing string 28.
- a number of annular seals 92 are mounted on the outer surface 84 and sealingly engage the outer tubing string 28 when the safety valve 10 is positioned as desired in the well bore 30.
- the seals 92 each may comprise any conventional face-type seal which is made from any suitable metallic, elastomeric or non-metallic material, depending on the expected pressures and fluids in the production bore 30.
- one or more of the seals 92 may comprise a radially energized seal which is expanded into sealing engagement by the pressure in the production bore 30 or by an energizing mechanism (not shown).
- one seal 92 could comprise a separate packoff which is installed between the body 78 and the outer tubing string 28 once the safety valve 10 is positioned in the production bore 30. Once the seals 92 are engaged against the outer tubing string 28, the body 78 will form a pressure containing barrier between the reservoir and the portion of the production bore 30 located above the safety valve 10.
- the safety valve 10 also comprises at least one flow passage 94 which extends generally axially through the body 78, and a closure member 96 which is operable to selectively open and close the flow passage.
- the closure member 96 is oriented longitudinally within the body 78 so as to occupy a minimum of the radial cross sectional area of the body. Accordingly, the flow passage 94 ideally includes at least one transverse branch across which the closure member 96 can operate.
- the flow passage 94 includes a transverse branch 98, an upper axial branch 100 which extends between the transverse branch and the top surface 80 and a lower axial branch 102 which extends between the transverse branch and the bottom surface 82.
- the flow passage 94 could have many different configurations, as long as it communicates between the portions of the production bore 30 which are located above and below the body 78.
- the closure member 96 is a hydraulically operated gate valve such as is described in U. S. Patent Application Publication No. 20010042618, which is commonly owned herewith.
- the gate valve 96 comprises a gate cavity 104 which extends generally axially through the body 78 across the transverse branch 98, a pair of ring-shaped seats 106 which are positioned on opposite sides of the gate cavity, and a gate 108 which is disposed between the seats.
- the gate valve 96 also includes an actuating mechanism 110 which is positioned in a bore 112 that extends axially through the body 78 above the gate cavity 104.
- the actuating mechanism 110 is connected to the gate 108 by a valve stem 114, which is ideally sealed to the body 78 by a conventional stem packing 116 that is retained within the bore 112 by a gland nut 118.
- each seat 106 is preferably a floating-type seat which is positioned in a seat pocket 120 that is formed at the intersection of the gate cavity 104 and the transverse branch 98.
- Each seat 106 is ideally sealed to its corresponding seat pocket 120 by an annular seal 122 and is biased against the gate 108 by a Belleville washer 124.
- each seat comprises a coaxial through bore 126 which is aligned with the transverse branch 98.
- the actuating mechanism 110 is preferably operable by hydraulic pressure to move the gate 108 from the closed position to the open position and to hold the gate in the open position until the hydraulic pressure is relieved.
- the actuating mechanism 110 comprises a piston 130 which is connected to the valve stem 114 and is sealed to the bore 112 by an annular seal 132. Hydraulic pressure is communicated to a portion of the bore 112 located above the piston 130 by a control line 134 which is connected between a suitable fitting 136 in the top of the bore and, for example, the service and control conduit 48 in the tubing hanger 14 ( Figure 1A).
- the service and control conduit 48 is connected to a corresponding service and control line 46 in the controls cap 40, which in turn is connected through the jumper 44 to a source of hydraulic pressure (not shown).
- the safety valve 10 may also comprise a pressure compensation port 138 which communicates with a portion of the bore 112 located below the piston 130 and is connected to a ballast tank or the like (not shown) via a fitting 140 and a control line 142.
- the actuating mechanism 110 also comprises a return biasing mechanism to force the gate 108 into the closed position in the absence of a predetermined amount of hydraulic pressure above the piston 132.
- the return biasing mechanism comprises a compression spring 144 which is operatively engaged between the gland nut 118 and the piston 132.
- the spring 144 is designed to exert a desired upward force on the piston 132.
- closure member 96 is described herein as being a hydraulically operated gate valve, other types of valves may be suitable for use in the safety valve 10.
- the closure member 96 could comprise any suitable hydraulically or electrically operated gate valve, ball valve, plug valve or flapper valve.
- the closure member 96 could comprise any of the known variety of storm choke valves. Therefore, the present invention should not be limited to any particular closure member 96.
- the safety valve 10 has been described in the context of the exemplary central circulation completion system 12, the safety valve can be used in virtually any completion system in which the well fluids are produced through the annulus between two concentric tubular members.
- the safety valve 10 can be used in a more traditional type completion system in which a production tubing string is suspended within a production casing string and the well fluids are produced through the annulus between the production tubing and production casing strings. Therefore, the present invention should not be limited by the particular completion system in which the safety valve 10 is employed.
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- Mining & Mineral Resources (AREA)
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- Environmental & Geological Engineering (AREA)
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- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Safety Valves (AREA)
- Valve Housings (AREA)
Description
- The present invention relates to a downhole safety valve for a central circulation completion system. More particularly, the invention relates to a valve for selectively sealing the annular production bore between the inner tubing string and the outer tubing string in a central circulation completion system.
- In traditional subsea completion systems, a tubing string is suspended from a tubing hanger which is landed in a wellhead housing or in a christmas tree that is installed over the wellhead housing. The tubing string extends into the hydrocarbon reservoir and defines a production bore through which well fluids may be produced. In addition, the tubing string is usually positioned within a casing string which is typically suspended from the wellhead housing. The casing string also extends into the reservoir, and the annulus between the tubing string and the casing string defines a service bore through which fluids may be circulated, for example during installation of the completion system.
- Subsea completion systems normally comprise at least one downhole safety valve, such as a surface controlled subsea safety valve ("SCSSV"), which functions to close off the production bore in the event of an emergency. A typical prior art SCSSV comprises a ball valve which is disposed in a cylindrical housing that is mounted within or between successive sections of the tubing string. The ball valve is held in the open position by hydraulic control pressure but is biased toward the closed position by a spring or the like. Accordingly, if a need to close off the production bore arises, the hydraulic pressure is relieved, thus allowing the valve to close.
- In central circulation completion systems, examples of which are described in International Publication Number WO01/81710A1, the roles of the production and service bores are largely reversed. Thus, in such systems the inner tubing string defines a service bore which may be used to circulate fluids during installation and workover operations. In addition, the annulus between the inner tubing string and a second, outer tubing string defines a production bore through which well fluids are produced.
- As with traditional subsea completion systems, central circulation completion systems must also be provided with means to shut off the production bore in the event of an emergency. However, since most downhole safety valves are designed to be used with conventional completion systems, wherein well fluids are communicated through the inner tubing string, they generally cannot be used with central circulation completion systems.
- In accordance with the present invention, these and other limitations in the prior art are overcome by providing a downhole safety valve for a central circulation completion system comprising an inner tubing string which extends through an outer tubing string and a production bore which is defined between the inner and outer tubing strings. The downhole safety valve comprises a generally cylindrical body which includes an outer surface and a through bore that extends generally axially through the body, a mechanism for securing the body to the inner tubing string, and at least one seal for sealing the body to the outer tubing string. In this manner, the body forms a pressure barrier between a first portion of the production bore located below the body and a second portion of the production bore located above the body. The downhole safety valve also comprises at least one flow passage which extends through the body and communicates between the first and second portions of the production bore, and at least one closure member which is disposed across the flow passage. Thus, fluid flow between the first and second portions of the production bore is controlled by the closure member. The inner tubing string comprises at least first and second successive sections, the securing means comprises first and second threaded receptacles which are aligned with the through bore, and the first and second sections are threadedly connected to corresponding ones of the first and second receptacles.
- In accordance with one embodiment of the invention, the closure member comprises a gate valve which includes a gate that is movable across the flow passage. In addition, the gate valve includes an actuating mechanism for moving the gate between a closed position in which a hole in the gate is offset from the flow passage and an open position in which the hole is aligned with the flow passage. The actuating mechanism comprises a piston which is connected to the gate and which is responsive to a predetermined amount of hydraulic pressure to move the gate from the closed position to the open position. The actuating mechanism also comprises a return biasing mechanism which forces the gate from the open position to the closed position in the absence of the predetermined amount of hydraulic pressure.
- Thus, the downhole safety valve of the present invention forms an effective pressure barrier for the annulus-shaped production bore of the central circulation completion system. In addition, the safety valve permits well fluids to flow through the production bore only when a predetermined amount of hydraulic pressure is applied to the actuating mechanism. In the absence of this hydraulic pressure, the return biasing mechanism will close the safety valve and thereby close off the production bore.
- These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings.
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- Figure 1A is a representation of the top portion of an exemplary central circulation completion system, showing a tubing hanger landed in a christmas tree which is installed on a wellhead housing;
- Figure 1B is a representation of the bottom portion of the central circulation completion system of Figure 1A;
- Figure 2 is a left half cross sectional view of the safety valve of the present invention shown installed between an inner tubing string and an outer tubing string; and
- Figure 3 is an enlarged cross sectional view of the gate and seat portions of the safety valve of Figure 2.
- Referring to Figures 1A and 1B, the downhole safety valve of the present invention, generally 10, is shown installed in an exemplary central
circulation completion system 12. As described in the aforementioned International Publication Number WO O1 /81710 A1, a central circulation completion system can take many forms. In the embodiment shown in Figures 1A and 1B, for example, the centralcirculation completion system 12 comprises atubing hanger 14 which is supported in achristmas tree 16 that is installed on awellhead housing 18. Thewellhead housing 18 in turn is mounted to the top of acasing string 20 which extends into the hydrocarbon reservoir. Thecasing string 20 may comprise a number of sections ofexpandable casing 20a, each of which is successively installed using conventional methods. In addition, aliner section 22 comprising a linertop isolation valve 24 may be installed below the lowermost section ofexpandable casing 22. - The exemplary central
circulation completion system 12 also comprises aninner tubing string 26, which is suspended from thetubing hanger 14 and extends approximately to the bottom of thecasing string 20, and anouter tubing string 28, which is run in through thewellhead housing 18 and expanded into sealing engagement with theliner section 24, thecasing string 20 and the wellhead housing in a known manner. In this fashion, aproduction bore 30 is formed between the inner andouter tubing strings service bore 32 is formed within the inner tubing string. Theproduction bore 30 is used to communicate well fluids from the reservoir to thechristmas tree 16 during the production mode of operation, and theservice bore 32 is used to circulate fluids between thetubing hanger 14 and the reservoir during installation and well servicing operations. If required, a remotely actuatableservice isolation valve 34 may be installed in the bottom of theinner tubing string 26 to prevent well fluids from entering theservice bore 32 during the production mode of operation. - As shown in Figure 1A, the
christmas tree 16 comprises acentral bore 36 which communicates with the production bore 30. Also, thetubing hanger 14 is sealed within thecentral bore 36 to form a pressure barrier between the production bore 30 and the environment. If required or desired, atree cap 38 may be installed in thecentral bore 36 above thetubing hanger 14, and acontrols cap 40 comprising a number of remote wet-mate couplers 42 may be removably secured to thetree cap 38 to provide an interface between anexternal jumper 44 and a number of service and control lines 46 in the tree cap. At least one of these service and control lines 46 is preferably connected with a corresponding service andcontrol conduit 48 in thetubing hanger 14 via a remote subseamatable coupler 50 for reasons which will be described below. - The
christmas tree 16 also includes a number of conduits to effect the production of the well fluids and to facilitate the servicing of the well. For example, thechristmas tree 16 may comprise aproduction conduit 52 which communicates with the production bore 30, aproduction bypass conduit 54 which extends between the production conduit and a portion of thecentral bore 36 located above thetubing hanger 14, aservice conduit 56 which communicates with aservice outlet 58 in thetubing hanger 14 that in turn is connected with theservice bore 32, aworkover conduit 60 which extends between the service conduit and a portion of the central bore located above the tubing hanger or thetree cap 38, and acrossover conduit 62 which is connected between the production conduit and the service conduit. Thechristmas tree 16 typically also includes a number of valves to control the flow of fluids through these conduits. Thus, thechristmas tree 16 may comprise aproduction master valve 64 and aproduction wing valve 66 in theproduction conduit 52, aproduction bypass valve 68 in theproduction bypass conduit 54, aservice master valve 70 and aservice wing valve 72 in theservice conduit 56, aworkover valve 74 in theworkover conduit 60, and acrossover valve 76 in thecrossover conduit 62. These valves are normally manually or hydraulically actuatable gate valves or the like. - In accordance with the present invention, the
safety valve 10 is positioned between the inner andouter tubing strings safety valve 10 comprises a generallycylindrical body 78 which has atop surface 80, abottom surface 82, anouter surface 84 and an annular throughbore 86 that extends between the top and bottom surfaces. The diameter of theouter surface 84 is sized to be slightly smaller than the diameter of theouter tubing string 28, and the diameter of thethrough bore 86 is preferably selected to be approximately the same as the diameter of theinner tubing string 26. In this manner, thebody 78 will substantially fill the annular void between the inner andouter tubing strings - The
safety valve 10 is deployed with theinner tubing string 26 and is therefore secured and sealed to the inner tubing string prior to being lowered into theproduction bore 30. For example, successive sections of theinner tubing string 26 may be threaded into upper and lower threadedreceptacles through bore 86. Alternatively, thebody 78 may be secured to theinner tubing string 26 using one or more conventional mechanical fasteners (not shown). Depending on the mode of attachment of thesafety valve 10 to theinner tubing string 26, one or more conventional seals (not shown) may be provided to seal thebody 78 to the inner tubing string. - The
safety valve 10 also includes suitable means to seal thebody 78 to theouter tubing string 28. In the illustrative embodiment of the invention shown in Figure 2, a number ofannular seals 92 are mounted on theouter surface 84 and sealingly engage theouter tubing string 28 when thesafety valve 10 is positioned as desired in the well bore 30. Theseals 92 each may comprise any conventional face-type seal which is made from any suitable metallic, elastomeric or non-metallic material, depending on the expected pressures and fluids in the production bore 30. Alternatively, one or more of theseals 92 may comprise a radially energized seal which is expanded into sealing engagement by the pressure in the production bore 30 or by an energizing mechanism (not shown). Also, oneseal 92 could comprise a separate packoff which is installed between thebody 78 and theouter tubing string 28 once thesafety valve 10 is positioned in the production bore 30. Once theseals 92 are engaged against theouter tubing string 28, thebody 78 will form a pressure containing barrier between the reservoir and the portion of the production bore 30 located above thesafety valve 10. - Referring still to Figure 2, the
safety valve 10 also comprises at least oneflow passage 94 which extends generally axially through thebody 78, and aclosure member 96 which is operable to selectively open and close the flow passage. In a preferred embodiment of the invention, theclosure member 96 is oriented longitudinally within thebody 78 so as to occupy a minimum of the radial cross sectional area of the body. Accordingly, theflow passage 94 ideally includes at least one transverse branch across which theclosure member 96 can operate. In the embodiment of the invention shown in Figure 2, for example, theflow passage 94 includes atransverse branch 98, an upperaxial branch 100 which extends between the transverse branch and thetop surface 80 and a loweraxial branch 102 which extends between the transverse branch and thebottom surface 82. Of course, theflow passage 94 could have many different configurations, as long as it communicates between the portions of the production bore 30 which are located above and below thebody 78. - In a preferred embodiment of the invention, the
closure member 96 is a hydraulically operated gate valve such as is described in U. S. Patent Application Publication No. 20010042618, which is commonly owned herewith. As shown in Figure 2, thegate valve 96 comprises agate cavity 104 which extends generally axially through thebody 78 across thetransverse branch 98, a pair of ring-shapedseats 106 which are positioned on opposite sides of the gate cavity, and agate 108 which is disposed between the seats. Thegate valve 96 also includes anactuating mechanism 110 which is positioned in abore 112 that extends axially through thebody 78 above thegate cavity 104. Theactuating mechanism 110 is connected to thegate 108 by avalve stem 114, which is ideally sealed to thebody 78 by a conventional stem packing 116 that is retained within thebore 112 by agland nut 118. - Referring to Figure 3, each
seat 106 is preferably a floating-type seat which is positioned in aseat pocket 120 that is formed at the intersection of thegate cavity 104 and thetransverse branch 98. Eachseat 106 is ideally sealed to itscorresponding seat pocket 120 by anannular seal 122 and is biased against thegate 108 by aBelleville washer 124. In addition, each seat comprises a coaxial throughbore 126 which is aligned with thetransverse branch 98. - When the
gate valve 96 is in the closed position shown in Figure 3, ahole 128 which extends transversely through thegate 108 is offset from the through bores 126. In this position, thegate 108 seals against thedownstream seat 106 and thereby prevents fluid from flowing through thetransverse branch 98. When thegate valve 96 is in the open position (not shown), thehole 128 is aligned with the throughbores 126, and fluid is therefore allowed to flow through thetransverse branch 98. - Referring again to Figure 2, the
actuating mechanism 110 is preferably operable by hydraulic pressure to move thegate 108 from the closed position to the open position and to hold the gate in the open position until the hydraulic pressure is relieved. In the illustrative embodiment of the invention shown in Figure 2, theactuating mechanism 110 comprises a piston 130 which is connected to thevalve stem 114 and is sealed to thebore 112 by anannular seal 132. Hydraulic pressure is communicated to a portion of thebore 112 located above the piston 130 by acontrol line 134 which is connected between asuitable fitting 136 in the top of the bore and, for example, the service and controlconduit 48 in the tubing hanger 14 (Figure 1A). In this example, the service and controlconduit 48 is connected to a corresponding service and control line 46 in the controls cap 40, which in turn is connected through thejumper 44 to a source of hydraulic pressure (not shown). Thesafety valve 10 may also comprise apressure compensation port 138 which communicates with a portion of thebore 112 located below the piston 130 and is connected to a ballast tank or the like (not shown) via a fitting 140 and acontrol line 142. - As shown, the
actuating mechanism 110 also comprises a return biasing mechanism to force thegate 108 into the closed position in the absence of a predetermined amount of hydraulic pressure above thepiston 132. In the illustrative embodiment of the invention shown in Figure 2, the return biasing mechanism comprises acompression spring 144 which is operatively engaged between thegland nut 118 and thepiston 132. Thespring 144 is designed to exert a desired upward force on thepiston 132. Thus, when the hydraulic pressure above thepiston 132 is insufficient to overcome the upward force from thespring 144, thegate 108 will move from the open position to the closed position. Therefore, thesafety valve 10 is a "fail close" device. - In operation of the
safety valve 10, sufficient hydraulic pressure is communicated to thebore 112 above the piston 130 to force the piston downward against the return force of thespring 144. The downward movement of the piston 130 will push thevalve stem 114 downward, which in turn will move thegate 108 from the closed position to the open position. In this position, well fluids are free to flow through theflow passage 94 and up through the production bore 30 to thechristmas tree 16. In the event a need arises to close off the production bore 30, the hydraulic pressure above the piston 130 is relieved. This will allow thespring 144 to force the piston 130 upward, which in turn will pull thevalve stem 114 upward and thereby move thegate 108 from the open position to the closed position. In this position, well fluids are prevented from flowing through theflow passage 94, and thesafety valve 10 therefore forms an effective pressure barrier between the reservoir and the portion of the production bore 30 located above the valve. - Although the
closure member 96 is described herein as being a hydraulically operated gate valve, other types of valves may be suitable for use in thesafety valve 10. For example, theclosure member 96 could comprise any suitable hydraulically or electrically operated gate valve, ball valve, plug valve or flapper valve. Also, theclosure member 96 could comprise any of the known variety of storm choke valves. Therefore, the present invention should not be limited to anyparticular closure member 96. - Also, although the
safety valve 10 has been described in the context of the exemplary centralcirculation completion system 12, the safety valve can be used in virtually any completion system in which the well fluids are produced through the annulus between two concentric tubular members. For example, thesafety valve 10 can be used in a more traditional type completion system in which a production tubing string is suspended within a production casing string and the well fluids are produced through the annulus between the production tubing and production casing strings. Therefore, the present invention should not be limited by the particular completion system in which thesafety valve 10 is employed. - It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details within the scope of the invention as defined in the claims.
Claims (11)
- A central circulation completion system (12) which comprises an inner tubular member (26) that extends through an outer tubular member (28), a production bore (30) which is defined between the inner and outer tubular members, and a downhole safety valve (10);
characterised in that the downhole safety valve comprises a generally cylindrical body (78) which includes an outer surface (84) and a through bore (32) that extends generally axially through the body;
means (88, 90) for securing the body to the inner tubular member;
means (92) for sealing the body to the outer tubular member;
wherein the body forms a pressure barrier between a first portion of the production bore located below the body and a second portion of the production bore located above the body;
at least one flow passage (94) which extends through the body and communicates between the first and second portions of the production bore; and at least one closure member (96) which is disposed across the flow passage;
wherein fluid flow between the first and second portions of the production bore is controlled by the closure member;
wherein the inner tubular member (26) comprises at least first and second successive sections, the securing means comprises first (88) and second (90) receptacles which are aligned with the through bore (32), and the first and second sections are connected to corresponding ones of the first and second receptacles. - The central circulation completion system of claim 1, wherein the securing means comprises first and second threaded receptacles (88, 90) which are aligned with the through bore (32), and the first and second sections are threadedly connected to corresponding ones of the first and second receptacles.
- The central circulation completion system claim 1 or 2, wherein the sealing means comprises at least one annular face seal (92) which is mounted on the outer surface (84).
- The central circulation completion system of claim 1, 2 or 3, wherein the closure member comprises a gate valve (96) which includes a gate (108) that is movable across the flow passage (94).
- The central circulation completion system of claim 4, wherein the flow passage (94) comprises a transverse branch (98) which is connected to an axial branch (100, 102), the gate valve comprises a gate cavity (104) which extends through the body across the transverse branch, and the gate (108) is disposed in the gate cavity.
- The central circulation completion system of claim 5, wherein the gate (108) is disposed between a pair of seats (106) which each comprise a through bore (126) that aligns with the flow passage (94).
- The central circulation completion system of claim 5 or 6, wherein the gate valve (96) further comprises means (110) for moving the gate (108) between a closed position in which a hole (128) in the gate (108) is offset from the flow passage (96) and an open position in which the hole is aligned with the flow passage.
- The central circulation completion system of claim 7, wherein the moving means (110) comprises a piston (130) which is connected to the gate (108) and which is responsive to a predetermined amount of hydraulic pressure to move the gate from the closed position to the open position.
- The central circulation completion system of claim 8, wherein the piston (130) is movable within a conduit (112) that extends generally axially through the body (78).
- The central circulation completion system of claim 7, 8 or 9, wherein the moving means (110) further comprises a return biasing mechanism (144) which forces the gate (108) from the open position to the closed position in the absence of the predetermined amount of hydraulic pressure.
- The central circulation completion system of claim 10, wherein the return biasing mechanism comprises a compression spring (144) which is operatively engaged between the piston (130) and the body (78).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2002/037395 WO2004048748A1 (en) | 2002-11-21 | 2002-11-21 | Downhole safety valve for central circulation completion system |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1570153A1 EP1570153A1 (en) | 2005-09-07 |
EP1570153B1 true EP1570153B1 (en) | 2006-03-29 |
Family
ID=32391437
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP02793981A Expired - Lifetime EP1570153B1 (en) | 2002-11-21 | 2002-11-21 | Downhole safety valve for central circulation completion system |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1570153B1 (en) |
AU (1) | AU2002359441A1 (en) |
NO (1) | NO20053026L (en) |
WO (1) | WO2004048748A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9428989B2 (en) | 2012-01-20 | 2016-08-30 | Halliburton Energy Services, Inc. | Subterranean well interventionless flow restrictor bypass system |
EP2805011B1 (en) * | 2012-01-20 | 2017-12-06 | Halliburton Energy Services, Inc. | Subterranean well interventionless flow restrictor bypass system |
US8573311B2 (en) | 2012-01-20 | 2013-11-05 | Halliburton Energy Services, Inc. | Pressure pulse-initiated flow restrictor bypass system |
WO2020013706A1 (en) * | 2018-07-12 | 2020-01-16 | New Subsea Technology As | Improvements in completing wells |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT1215962B (en) * | 1988-03-02 | 1990-02-22 | Tecnomare S P A San Marco Vene | SAFETY SUBMARINE VALVE BLOCK, PARTICULARLY SUITABLE FOR RISERS OF OFFSHORE PLATFORMS. |
US6612368B2 (en) * | 2000-03-24 | 2003-09-02 | Fmc Technologies, Inc. | Flow completion apparatus |
US6942192B2 (en) * | 2000-03-24 | 2005-09-13 | Fmc Technologies, Inc. | Gate valve with flow-through gate |
EP1278934B1 (en) * | 2000-03-24 | 2005-08-24 | FMC Technologies, Inc. | Tubing hanger system with gate valve |
GB2361725B (en) * | 2000-04-27 | 2002-07-03 | Fmc Corp | Central circulation completion system |
-
2002
- 2002-11-21 AU AU2002359441A patent/AU2002359441A1/en not_active Abandoned
- 2002-11-21 WO PCT/US2002/037395 patent/WO2004048748A1/en not_active Application Discontinuation
- 2002-11-21 EP EP02793981A patent/EP1570153B1/en not_active Expired - Lifetime
-
2005
- 2005-06-20 NO NO20053026A patent/NO20053026L/en not_active Application Discontinuation
Also Published As
Publication number | Publication date |
---|---|
EP1570153A1 (en) | 2005-09-07 |
WO2004048748A1 (en) | 2004-06-10 |
AU2002359441A1 (en) | 2004-06-18 |
NO20053026L (en) | 2005-06-21 |
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