United States Patent [19]
`
`Kelly et al.
`
`[11] Patent Number:
`
`4,589,493
`
`[45] Date of Patent:
`
`May 20, 1986
`
`Primary Examiner—James A. Leppink
`Assistant Examiner—Hoang C. Dang
`Attorney, Agent. or Firm—Vinson & Elkins
`
`[57]
`
`ABSTRACT
`
`[54} SUBSEA WELLHEAD PRODUCTION
`APPARATUS WITH A RETRIEVABLE
`SUBSEA CHOKE
`
`[75]
`
`Inventors: Thomas P. Kelly; Edmund A. Fisher,
`both of Houston, Tex.
`
`[73] Assignee: Cameron Iron Works, Inc., Houston,
`Tex.
`
`[21] App]. No.: 596,068
`
`[22] Filed:
`
`Apr. 2, 1984
`
`Int. CL4 ............................................ .. E21B 43/01
`[s1]
`[52] U.S. Cl. .................................... 166/341; 166/344;
`137/798; 251/367
`[58] Field of Search ............. .. 166/344, 347. 341. 338,
`166/351; 285/157, 124; 251/367, 152, 153;
`137/798
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`........................ 285/157
`3/1942 Schfin et al.
`2,276,883
`3,688,840 9/1972 Curington et a1.
`....... 166/341
`3,820,558 6/ 1974 Mueller ............
`.. 251/367 X
`3,957,079
`5/1976 Whiteman
`166/338 X
`4,046,191 9/ 1977 Neath .......
`....... 166/352
`4,210,208
`7/1980 Shanks .....
`...... 166/352
`4,457,489 7/1984 Gilmore .......................... 166/344 X
`
`A subsea wellhead production apparatus including a
`retrievable subsea choke having a body having an inlet,
`an outlet extending therein from its lower surface and a
`collet connecting flange surrounding the lower end of
`said body, a passage in said body defining communica-
`tion between said inlet and said outlet, a valve seat in
`said body surrounding communication between said
`inlet and said outlet, a valve member movably mounted
`in said body to coact with said valve seat to control
`flow through said communication passage an actuator
`for moving said valve member toward and away from
`said valve seat, a flowline body having first and second
`passages opening on a surface of the body with a collet
`connecting flange surrounding said surface. An orient-
`ing key on said choke body and a muleshoe on said
`flowline body to orient and align said first passage with
`said inlet and said second passage with said outlet, and
`a remotely actuated collet connector surrounding a.nd
`supported on said flowline body and having collet lock-
`ing elements in position to engage the collet connecting
`flange.
`
`7 Claims, 3 Drawing Figures
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`4,589,493
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`SUBSEA WELLI-IEAD PRODUCTION APPARATUS
`WITH A RETRIEVABLE SUBSEA CHOKE
`
`BACKGROUND
`
`When water depth becomes too great to economi-
`cally allow the installation of fixed production plat-
`forms the wellhead trees are mounted subsea on the
`ocean floor. Due to the inaccessibility of the subsea tree,
`the producing well must be “killed” and the tree re-
`motely retrieved and brought to the surface of the
`water for any maintenance that might be required. Due
`to the time and expense involved in “killing” the well
`and retrieving the tree, redundant prsure containing
`valves have been used or where possible the valves
`have been installed at the surface. Due to their potential
`for high wear rates, the adjustable chokes have previ-
`ously been installed above the water surface. This has
`required a high pressure production flowline for each
`producing zone of each well in a given oil or gas field
`which would be routed from the subsea tree, along the
`ocean floor, to a gathering ship or platform. Also, since
`the various wells in a given field may not all have the
`same pressure their production cannot be comingled
`into one flowline and thereby use one surface located
`choke. Subsea chokes have been suggested for use in
`riser pressure equalization systems
`for controlling
`downhole pressure during drilling (U.S. Pat. No.
`4,210,208) and to circulate out formation influx of a
`formation kick without having the choke on the drill
`ship (U.S. Pat. No. 4,046,191).
`If the pressure reducing adjustable chokes could be
`installed directly onto the subsea trees then each well’s
`reduced pressure production could be directed into a
`single subsea gathering line with it being necessary to
`route only this one single gathering line along the ocean
`floor instead of multiple high pressure flow lines.
`SUMMARY
`
`The present invention provides an improved retriev-
`able subsea choke which has a body with an inlet and an
`outlet extending into said body from its lower surface
`which is surrounded by a collet connector flange, a
`passage extending 5 through the body to provide com-
`munication from the inlet to the outlet and with a valve
`seat surrounding such passage leading to the outlet, a
`valve chamber in the body with a valve member mov-
`ably mounted in the valve chamber, means for moving
`the valve member toward and- aways from the valve
`seat to control flow the valve.
`
`An object of the present invention is to provide an
`improved retrievable subsea choke which can be re-
`trieved from its connection to a subsea wellhead inde-
`
`pendent of the remainder of the components to which it
`is connected.
`
`Another object is to provide an improved subsea
`choke which with its operator can be packaged as an
`assembly which may be lowered, landed and installed
`on a subsea wellhead and also may be independently
`retrievable from such subsea wellhead.
`
`A further object is to provide an improved subsea
`choke which can be retrieved without the need of a
`diver.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`These and other objects and advantages of the pres-
`ent invention are hereinafter described and explained
`with reference to the drawings wherein:
`FIG. 1 is an elevation view of a deep subsea wellhead
`with the improved subsea choke of the present inven-
`tion installed thereon,
`FIG. 2 is a plan view of the wellhead shown in FIG.
`
`1.
`
`FIG. 3 is a detailed sectional view of the improved
`subsea choke the present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`As shown in FIGS. 1 and 2, subsea wellhead equip-
`ment 10 rests on the bottom and is connected to the
`upper end of well casing 12. Subsea wellhead equipment
`10 is landed on guide base 14 and connected by remote
`control to well casing 12 by remotely controlled con-
`nector 16. Christmas tree 18 with its control valves
`forms a portion of wellhead equipment 10. Line 20
`connects from the well production string to production
`flowline body or collet body 22 and line 24 connects
`from collet body 22 to the subsea flowline (not shown).
`Improved subsea choke assembly 26, as hereinafter
`described, is connected to collet body 22 by remotely
`controlled connection means such as collet connector
`28. It should be noted that any other suitable remotely
`actuated connection means may be used with suitable
`preparation of the mating portions of body 22 and body
`30, such as the connection means disclosed in U.S. Pat.
`No. 3,986,729.
`As shown in FIG. 3, assembly 26 includes body 30
`having collet flange 32 surrounding its lower surface 34,
`remotely controlled collet connector 28 and choke
`actuator 36. Collet body 22 includes upper surface 38
`which is adapted to mate with surface 34 which is sur-
`rounded by collet flange 40. Collet connector 28 in-
`cludes plate 42 which is suitably secured to body 30 by
`screws 44 and supports actuators 46 which move cam
`sleeve 48 to cause locking elements 50 to engage or
`release from flanges 32 and 40. Other connecting means
`which may be remotely actuated may be used, such as
`the circumferentially discontinuous locking ring struc-
`ture disclosed in U.S. Pat. No. 3,986,729.
`In order to ensure proper alignment of body 30 and
`collet body 22 orienting means 52 is provided. Such
`orienting means 52 includes plate 54 secured around
`collet body 22 and having upstanding annular collar 56
`extending upwardly as shown from the periphery of
`plate 54. Mule shoe 58 is secured around the interior of
`collar 56 which terminates in slot 60. Also, orienting
`key 62 extending from the exterior of connector 28 is
`positioned to coact with mule shoe 58 and to engage in
`slot 60 and thus orient choke assembly 26 with respect
`to collet body 22 as it is lowered into position.
`The structure of collet body 22 includes passage 64
`which is connected to line 20 and passage 66 which is
`connected to line 24. Both passages 64 and 66 extend to
`and are open at surface 38. When body 30 has been
`landed on collet body 22, passage 64 is aligned with
`inlet 68 and passage 66 is aligned with outlet 70 and
`suitable sealing means, as shown, are provided to main-
`tain sealed communication between these connections.
`Body 30 includes chamber 72 which is in communica-
`tion with inlet 68 and passage 74 extends through body
`30 to valve chamber 76. Valve chamber 76 is in commu-
`
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`nication to outlet 70 through valve seat 78. Valve mem-
`ber 80 is mounted in body 30 as hereinafter described
`for movement toward and away from valve seat 78 to
`control
`the flow of production fluids therethrough.
`Valve seat 78 is defined by sleeve 82 which is threaded
`into the passage in body 30 leading to outlet 70 and is
`preferably of a material which is resistant to the erosive
`action of the fluids which may include some solids and
`which flow therethrough at substantial velocity. Outlet
`70 is lined with sleeve 84 which extends beyond surface
`34 to provide an erosion resistant lining for outlet 70.
`Valve member 80 is mounted on shaft 86 which ex-
`tends and provides the connection to actuator 36 and is
`supported in bushing 88 which is threaded into the
`opening of valve chamber 76 to the exterior upper sur-
`face of body 30. Valve member 80 includes erosion
`resistant sleeve 90 which is suitably mounted on shaft 86
`and coacts with valve seat 78 to control flow.
`- Block 92 is positioned within chamber 72 and is pref-
`erably made of an erosion resistant material. Passage 94
`extends through block 92 in the shape of an elbow to
`provide communication between passage 68 and pas-
`sage 74. Since chamber 72 opens to the upper surface of
`body 30 in order for block 92 to be installed therein,
`plug 96 is secured therein and sealed to ensure that
`chamber 72 is sealed and the block 92 is secured in its
`desired position.
`While the embodiment shown has the mating surfaces
`34 and 38 on choke body 30 and collet body 22 being
`their lower and upper surfaces respectively these mat-
`ing surfaces could be positioned vertically to be side
`surfaces or have some other orientation as long as they
`are mating and provide communication from passage 64
`to inlet 68 and from outlet 70 to passage 66.
`As may be seen from the foregoing description, the
`improved subsea choke is easily retrievable and it is
`retrievable without disturbing any of the wellhead
`equipment. It may be retrieved on a wire line, a drill
`pipe or by a-remotely operated vehicle.
`What is claimed is:
`1. A subsea wellhead production apparatus compris-
`“IS
`a subsea production flowline body having first and
`second passages opening on a surface of said body
`and means surrounding said body surface for coact-
`ing with a connecting means,
`a choke body having an inlet and an outlet extending
`therein from one of its surfaces and means sur-
`rounding said surface for coacting with a connect-
`ing means,
`means in said choke body for conducting flow from
`said inlet through a valve seat to said outlet,
`a valve member movably mounted in said body to
`coact with said valve seat to control flow through
`said valve seat,
`means for moving said valve member with respect to
`said valve seat, and
`remotely actuated means for releasably connecting
`said coacting means of said choke body to said
`coacting means of said flowline body with said first
`passage in communication with said inlet and said
`second passage in communication with said outlet
`whereby flow from said first passage to said second
`passage is controlled by said valve member.
`2. An apparatus according to claim 1 including
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`4,589,493
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`orienting means between said flowline body and said
`choke body to align said first passage with said
`inlet and said second passage with said outlet.
`3. An apparatus according to claim 2 wherein said
`orienting means includes
`a mule shoe supported from said flowline body, and
`a key supported from said choke body in position to
`engage said mule shoe on landing of said choke
`body against said flowline body.
`4. An apparatus according to claim 2 including
`means in said choke body and on said valve member
`for resisting erosion of fluids flowing therethrough.
`S. An apparatus according to claim 2 wherein said
`connecting means includes
`a remotely actuated collet connector, and
`said coacting means includes
`collet flanges on said flowline body and said choke
`body for engagement by said collet connector.
`6. A retrievable subsea choke comprising
`a body having an inlet and an outlet extending therein
`from one of its surfaces and a collect flange sur-
`rounding said surface for coacting with a remotely
`actuated releasable collet connector,
`means in said body for conducting flow from said
`inlet through a valve seat to said outlet,
`a valve member movably mounted in said body to
`coact with said valve seat to control flow through
`.said valve seat,
`means for landing on a subsea wallhead, said body
`and a remotely actuated collect connector for con-
`necting said body to a subsea production flowline
`to control flow from a subsea wellhead production
`line to a subsea flowline, and
`an orienting key mounted on said collect connected
`which is positioned to engage a subsea orienting
`device and provide proper orientation of said body
`and connector as they are landed at their intended
`subsea location.
`7. A retrievable subsea choke comprising
`a body having an inlet and outlet extending therein
`from one of its surfaces and a collet flange sur-
`rounding said surface for coacting with a remotely
`actuated releasable collet connector,
`means in said body for conducting flow from said
`inlet through a valve seat to said outlet,
`a sleeve of erosion resistant material mounted in said
`conducting means leading to said outlet to define
`said valve seat,
`a valve member movably mounted in said body to
`coact with said valve seat to control flow through
`said valve seat and having a sleeve thereon of ero-
`sion resistant material,
`’
`means for landing on a subsea wellhead, said body
`and a remotely actuated collect connector for con-
`necting said body to a subsea production flowline
`to control flow from a subsea wellhead production
`line to a subsea flowline,
`an opening in said body in said conducting Hieans
`between said inlet and said valve seat,
`a block of erosion resistant material positioned in said
`opening and defining an elbow in said conducting
`means,
`means for securing and sealing said block and said
`opening, and
`an orienting key mounted on said collet connector
`which is positioned to engage a subsea orienting
`device and provide proper orientation of said body
`and connector as they are landed at their intended
`subsea location.i
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