(19) United States
`(2) Patent Application Publication (10) Pub. No.: US 2002/0070026 A1
`Fenton et al.
`(43) Pub. Date:
`Jun. 13, 2002
`
`US 20020070026A1
`
`(52) U.S. Cl. ......................... 166/368; 166/347; 166/344;
`166/95.1; 166/97.1
`
`(57)
`
`ABSTRACT
`
`A subsea well apparatus has features for controlling and
`monitoring production fluid flow from a well. A Christmas
`tree lands on a subsea wellhead, the tree having a tubular,
`open upper end. A first flow passage extends from a lower
`end of the tree to the upper end for communicating fluid with
`the well. A second flow passage extends downward from the
`upper end of the tree and has an outlet on a sidewall of the
`tree for communicating with a flowline. A production mod
`ule lands on and is retrievable from the upper end of the tree,
`the module having a flow loop with one end in communi
`cation with the first flow passage and another end in com
`munication with the second flow passage. At least one flow
`interface device is located in the loop of the production
`module. The flow interface device may be used to monitor
`or control the flow and may be a temperature or pressure
`
`(51) Int. Cl." … E21B 43/01 sensor, a flow or multi-phase flow meter, or a choke.
`
`(54) LIGHT-INTERVENTION SUBSEATREE
`SYSTEM
`(76) Inventors: Stephen P. Fenton, Inverurie (GB);
`John H. Osborne, Braes (GB); Rolf
`Nordaunet, Tranby (NO)
`Correspondence Address:
`James E. Bradley
`BRACEWELL & PATTERSON
`P.O. Box 61389
`Houston, TX 77208-1389 (US)
`
`(21) Appl. No.:
`(22) Filed:
`
`09/732,817
`Dec. 8, 2000
`
`Related U.S. Application Data
`(63) Non-provisional of provisional application No.
`60/170,061, filed on Dec. 10, 1999.
`
`Publication Classification
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`:
`
`Ö
`
`
`
`|
`: E
`
`
`
`
`
`OSS Exhibit 2019, pg. 1
`FMC vs. OSS
`IPR2016-00495
`
`

`
`Patent Application Publication Jun. 13, 2002 Sheet 1 of 2
`
`US 2002/0070026 A1
`
`49*TETE:
`º &# Åker
`Hz §§
`ºr sº
`i
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`S
`
`N (4. i N :
`. *I. i ;
`4% º N
`
`
`
`OSS Exhibit 2019, pg. 2
`FMC vs. OSS
`IPR2016-00495
`
`

`
`Patent Application Publication Jun. 13, 2002 Sheet 2 of 2
`
`US 2002/0070026 A1
`
`
`
`
`
`|
`
`+N
`ºries
`=ººl tº
`
`OSS Exhibit 2019, pg. 3
`FMC vs. OSS
`IPR2016-00495
`
`

`
`US 2002/0070026 A1
`
`Jun. 13, 2002
`
`LIGHT-INTERVENTION SUBSEA TREE SYSTEM
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`[0001] Benefit is herein claimed of the filing date under 35
`USC §119 and/or $120 and CFR 1.78 to United States
`Provisional Patent Application Serial No. 60/170,061, filed
`on Dec. 10, 1999, entitled “Light Intervention Subsea Tree
`System.”
`
`BACKGROUND OF THE INVENTION
`[0002] 1. Field of the Invention
`[0003] This invention relates in general to subsea oil and
`gas production systems and in particular to a subsea tree
`assembly having certain components that are retrievable by
`a light-duty workover vessel.
`[0004] 2. Description of the Prior Art
`[0005] A conventional subsea wellhead assembly includes
`a wellhead housing which supports one or more casing
`hangers located at upper ends of strings of casing extending
`into the well. A production tree is landed on the wellhead for
`controlling the production of well fluids. The tree usually
`carries a choke and valves to control the flow and sensors to
`monitor the flow.
`[0006] With both conventional and horizontal trees, exter
`nal chokes and production valves are used to control the
`flow. If the valves or choke are in need of service, retrieval
`is difficult and may require the use of a remotely-operated
`vehicle. Various valves and controls have been located on an
`apparatus separately retrievable from the tree, but many of
`the components requiring service may require that the entire
`tree be removed.
`
`SUMMARY OF THE INVENTION
`[0007] A subsea well apparatus is provided for controlling
`and monitoring production fluid flow from a well. A Christ
`mas tree is adapted to land on a subsea wellhead, the tree
`having a tubular, open upper end. A first flow passage
`extends from a lower end of the tree to the upper end for
`communicating fluid with the well. A second flow passage
`extends downward from the upper end of the tree and has an
`outlet on a sidewall of the tree for communicating with a
`flowline. The second flow passage is connected to an annu
`lus access passage and is separated from the annulus access
`passage by a valve. A production module lands on and is
`retrievable from the upper end of the tree, the module having
`a flow loop with one end in communication with the first
`flow passage and another end in communication with the
`second flow passage. At least one flow interface device is
`located in the loop of the production module. The flow
`interface device may be used to monitor or control the flow
`and may be a temperature or pressure sensor, a flow or
`multi-phase flow meter, or a choke.
`
`DESCRIPTION OF THE DRAWINGS
`[0008] The novel features believed to be characteristic of
`the invention are set forth in the appended claims. The
`invention itself however, as well as a preferred mode of use,
`further objects and advantages thereof, will best be under
`stood by reference to the following detailed description of an
`
`illustrative embodiment when read in conjunction with the
`accompanying drawings, wherein:
`[0009] FIG. 1 is a sectional view illustrating a subsea tree
`constructed in accordance with this invention shown being
`landed on a subsea wellhead assembly.
`[0010] FIG. 2 is an enlarged sectional view of a produc
`tion module that lands on the subsea tree of FIG. 1.
`
`DESCRIPTION OF THE INVENTION
`[0011] Referring to FIG. 1, subsea wellhead assembly 11
`is conventional. It includes an outer low-pressure wellhead
`housing 13 that is located at the upper end of a string of a
`large diameter conductor that extends into the well to a first
`depth. An inner high-pressure wellhead housing 15 locates
`within outer wellhead housing 13 and protrudes above. Inner
`wellhead housing 15 is a tubular member secured to the
`upper end of large diameter casing that extends to a second
`depth in the well. The well will have typically two casing
`hangers 17. The lower one is secured to a string of casing
`that extends to a third depth in the well. The uppermost
`casing hanger 17 is secured to production casing 19 that
`extends to the total depth of the well. Subsea wellhead 11 has
`four guide posts 27 extending upward. The upper end of
`inner wellhead housing 15 is a tubular mandrel 29 having an
`exterior profile with grooves.
`[0012] A conventional tubing hanger 21 lands in the bore
`of inner wellhead housing 15 above the uppermost casing
`hanger 17. Tubing hanger 21 is secured to a string of tubing
`(not shown) extending into the well. Tubing hanger 21 has
`an axially extending production passage 23. An annulus
`passage 25 extends through tubing hanger 21 parallel to and
`offset from production passage 23. Production passage 23
`communicates with the interior of the string of tubing, while
`annulus passage 25 communicates with an annulus between
`the string of tubing and production casing 19.
`[0013] A production tree 31 is adapted to land on subsea
`wellhead 11 for controlling fluids produced from the well.
`Tree 31 may alternately be an injection tree for controlling
`fluids injected into the well. Production tree 31 has guide
`receptacles 33 that are received over guide posts 27 as tree
`assembly 31 is being lowered on guidelines 34. Tree 31 has
`a wellhead connector 35 on its lower end. Connector 35 is
`conventional, having dogs 36 that are hydraulically actuated
`for engaging the grooves on mandrel 29 or having a similar
`connection device using, for example, collets.
`[0014] An axial first or upward-flow production passage
`37 extends through tree 31. One or more master valves 39,
`preferably gate valves, selectively open and close upward
`flow production passage 37. An annulus access passage 41
`extends upward to the upper end of tree 31 parallel to and
`offset from upward-flow production passage 37. Annulus
`access passage 41 communicates with annulus passage 25 of
`tubing hanger 21, while production passage 37 communi
`cates with production passage 23 of tubing hanger 21.
`Annulus access passage 41 has two annulus valves 43, 45.
`An external cross-over line 48 extends from a port 47 in
`upward-flow production passage 37 to a port 49 in annulus
`access passage 41 between annulus valves 43, 45 to com
`municate annulus 25 with upward-flow production passage
`37. A valve (not shown) will also be contained in the
`cross-over line 48. Cross-over line 48 enables fluid to be
`
`OSS Exhibit 2019, pg. 4
`FMC vs. OSS
`IPR2016-00495
`
`

`
`US 2002/0070026 A1
`
`Jun. 13, 2002
`
`pumped down annulus access passage 41, through cross
`over line 48, and down production passage 37 to kill the
`well, if desired.
`[0015] Tree 31 also has a second or downward-flow pro
`duction passage 51 that extends upward from annulus access
`passage 41 above annulus valve 45. Downward-flow pro
`duction passage 51 is coaxial with annulus access passage
`41 and intersects annulus access passage 41 above annulus
`valve 45. Downward-flow passage 51 can communicate
`with the lower portion of annulus access passage 41 by
`opening annulus valves 43, 45. Downward-flow passage 51
`is parallel to and offset from upward-flow production pas
`sage 37 and leads to a lateral production passage 53 for
`controlling flow into an attached flowline. A production
`valve 55 is located in lateral production passage 53.
`[0016] The upper end of tree 31 is formed into a configu
`ration of a mandrel 57, having grooves on the exterior. Tree
`mandrel 57 has a smaller outer diameter than wellhead
`housing mandrel 29 in this embodiment. An upward facing
`funnel 59 surrounds tree mandrel 57 for guidance.
`[0017] A production module 61 is shown in FIG. 2.
`Production module 61 is adapted to land on tree mandrel 57.
`Production module 61 has a tree connector 63 on its lower
`end that is of a conventional design. Tree connector 63 has
`a plurality of dogs 65 that are moved radially inward into
`engagement with the profile on tree mandrel 57 (FIG. 1) by
`means of a cam ring 67 or has a similar connection device
`using, for example, collets. Hydraulic cylinders 69 move
`cam ring 67 upward and downward. Production module 61
`has an upward-flow passage 71 that is positioned to register
`with upward-flow production passage 37 (FIG. 1). Module
`upward-flow passage 71 leads upward to a cross-over pas
`sage 73. Cross-over passage 73 leads to a downward-flow
`passage 75 that is parallel to and offset from upward-flow
`passage 71. Downward-flow passage 75 is oriented to align
`and communicate with downward-flow production passage
`51 in tree 31 (FIG. 1). The set of internal flow passages
`comprising passages 71, 73, and 75 forms a flow loop within
`module 61. If an injection tree is used instead of a production
`tree, the flow directions in passages 71, 73, 75 of module 61
`will be reversed.
`[0018] One or more Flow interface devices can lie within
`or adjacent to and in communication with the flow loop of
`module 61. The devices may be a variety of types for
`controlling or measuring, such as a choke, a pressure or
`temperature sensor, or a flow meter. Shown in FIG. 2 is a
`choke assembly 77 located in cross-over passage 73. Choke
`assembly 77 is of a conventional design and used for
`variably restricting the flow of production fluid flowing
`through cross-over passage 73. An upstream pressure and
`temperature sensor 79 locates on the upstream side of choke
`77. A downstream pressure and temperature sensor 81
`locates on the downstream side of choke assembly 77. Also,
`preferably, a multi-phase flow meter is utilized for measur
`ing the flow rate through cross-over passage 73. Flow meter
`controls 83, shown schematically, are located at the upper
`end of production module 61 for serving the flow-metering
`hardware located in passage 73.
`[0019) Hydraulic and electric controls 85 for production
`module 61 and tree 31 are also located adjacent to flow
`meter controls 83. These controls 85 serve the various
`valves, such as master valve 39, annulus valves 43, 45, and
`
`production valve 55. An ROV panel 87 may be located on
`one side of production module 61 for allowing engagement
`by remote operated vehicles for performing various opera
`tions. Production module 61 has a lift wire attachment 89 on
`its upper end to enable it to be retrieved and re-installed by
`a light duty workover vessel (not shown) at the surface.
`Production module 61 may have an annular buoyant tank 91
`located near an upper portion of module 61. Tank 91 may be
`filled with air or a buoyant material to assist in retrieving
`module 61.
`[0020] In operation, the subsea well will be completed
`conventionally with a subsea wellhead assembly 11 as
`shown in FIG. 1. Tree 31 will be lowered on guide wires 34
`into engagement with mandrel 29 of wellhead housing 15.
`Then, production module 61 is lowered on a lift wire into
`engagement with mandrel 57 of tree 31 (FIG. 1) with the
`assistance of upward facing funnel 59 or guideposts.
`[0021] During production, well fluid will flow as indicated
`by the arrows up tubing hanger production passage 23 and
`tree production passage 37. The well fluid flows upward into
`upward-flow passage 71 of production module 61, shown in
`FIG. 2. As indicated by the arrows, well fluid flows through
`cross-over passage 73 and then through downward-flow
`passage 75. Choke 77 will control the rate of flow. Sensors
`79, 81 will monitor pressure and temperature. Flow meter
`controls 83, if utilized, will monitor the flow rate and water
`cut. The flow proceeds through downward-flow passage 75
`back into tree 31 via downward-flow passage 51 (FIG. 1).
`The production flow proceeds out lateral passage 53 to a
`flow line.
`[0022] The moveable components on tree 31, such as
`valves 39, 43, 45 and 55 typically require little maintenance.
`Intervention to change the valves or any other components
`of tree 31 is not expected to be frequently required. The
`components of production module 61 are more active and
`more subject to failure. These components include choke 77,
`flow meter controls 83 and the pressure and temperature
`sensors 79, 81. Production module 61 can be readily
`retrieved by a small vessel using a lift line to repair or
`replace any of these components or to allow communication
`with annulus access passage 41 at the top of the tree 31. The
`small vessel need not be large enough to run casing, tubing
`or to retrieve a tree.
`[0023] While the invention is shown in only one of its
`forms, it should be apparent to those skilled in the art that it
`is not so limited, but is susceptible to various changes
`without departing from the scope of the invention.
`
`1. A subsea well apparatus comprising:
`a christmas tree adapted to land on a subsea wellhead
`located at a well, the tree having a tubular, open upper
`end;
`a first flow passage extending from a lower end of the tree
`to the upper end for communicating fluid with the well;
`a second flow passage extending downward from the
`upper end of the tree and having an outlet on a sidewall
`of the tree for communicating a flowline;
`a production module that lands on and is retrievable from
`the upper end of the tree, the module having a flow loop
`
`OSS Exhibit 2019, pg. 5
`FMC vs. OSS
`IPR2016-00495
`
`

`
`US 2002/0070026 A1
`
`Jun. 13, 2002
`
`with one end in communication with the first flow
`passage and another end in communication with the
`second flow passage; and
`at least one flow interface device in the loop of the
`production module.
`2. The apparatus of claim 1, wherein the flow interface
`device comprises at least one of the following:
`a pressure sensor;
`a temperature sensor;
`a flow-rate sensor; and
`a choke.
`3. The apparatus of claim 1, wherein:
`the production module contains hydraulic controls for
`controlling valves in the tree.
`4. The apparatus of claim 1, wherein:
`the first flow passage handles production flow flowing
`upward from the well and the second flow passage
`discharges the production fluid to the flowline.
`5. The apparatus of claim 1, wherein:
`the first flow passage and the second flow passage are
`parallel.
`6. The apparatus of claim 1, further comprising:
`an annulus passage extending from the lower end of the
`tree to the upper end, the annulus passage being offset
`from the second flow passage.
`7. The apparatus of claim 1, further comprising:
`at least one buoyancy tank mounted to an upper portion of
`the module.
`8. A subsea well apparatus comprising:
`a christmas tree adapted to land on a subsea wellhead
`located at a well, the tree having a tubular, open upper
`end;
`a first flow passage extending downward from a lower end
`of the tree to the upper end for communicating fluid
`with the well, the first flow passage being for upward
`flowing production fluids from the well;
`a second flow passage extending from the upper end of the
`tree and having an outlet on a sidewall of the tree for
`communicating a flowline, the second flow passage
`being for downward-flowing production fluids;
`a production module that lands on and is retrievable from
`the upper end of the tree, the module having a set of
`continuous, internal flow passages connected to form a
`flow loop, one end of the flow loop being in commu
`nication with the first flow passage and another end of
`the flow loop being in communication with the second
`flow passage;
`at least one flow interface device in the loop of the
`production module; and
`wherein the flow interface device comprises at least one
`of the following:
`
`a pressure sensor;
`a temperature sensor;
`a flow-rate sensor; and
`a choke.
`9. The apparatus of claim 8, wherein:
`the production module contains hydraulic controls for
`controlling valves in the tree.
`10. The apparatus of claim 8, wherein:
`the first flow passage and the second flow passage are
`parallel.
`11. The apparatus of claim 8, wherein:
`the second flow passage extends to a lower end of the tree
`for communication with a tubing annulus; and
`a valve is located in the second flow passage between the
`outlet of the sidewall of the tree and the lower end of
`the tree.
`12. The apparatus of claim 8, further comprising:
`at least one buoyancy tank mounted to an upper portion of
`the module.
`13. A method of producing production fluids from a
`subsea well, the method comprising:
`landing a Christmas tree on a subsea wellhead located at
`a well, the tree having a tubular, open upper end;
`providing a first flow passage through the tree, the first
`flow passage extending from a lower end of the tree to
`the upper end for communicating fluid with the well;
`providing a second flow passage through the tree, the
`second flow passage extending downward from the
`upper end of the tree and having an outlet on a sidewall
`of the tree for communicating a flowline;
`landing a production module on the upper end of the tree,
`the module having a flow loop with one end in com
`munication with the first flow passage and another end
`in communication with the second flow passage;
`flowing production fluids up the first flow passage,
`through the flow loop of the module, and down the
`second flow passage to the flowline; and
`providing at least one flow interface device located within
`the flow loop of the production module, the device
`being in communication with the production fluids.
`14. The method of claim 13, further comprising:
`controlling at least one valve in the tree with hydraulic
`controls located in the production module.
`15. The method of claim 13, further comprising:
`measuring characteristics of the flow using the flow
`interface device, the measured characteristics including
`at least one of the following: pressure, temperature, and
`flow rate.
`16. The method of claim 13, further comprising:
`controlling the flow through the loop of the production
`module using the flow interface device, the device
`comprising a choke.
`
`OSS Exhibit 2019, pg. 6
`FMC vs. OSS
`IPR2016-00495