|Publication number||US20080128139 A1|
|Application number||US 11/942,230|
|Publication date||Jun 5, 2008|
|Filing date||Nov 19, 2007|
|Priority date||Nov 9, 2006|
|Publication number||11942230, 942230, US 2008/0128139 A1, US 2008/128139 A1, US 20080128139 A1, US 20080128139A1, US 2008128139 A1, US 2008128139A1, US-A1-20080128139, US-A1-2008128139, US2008/0128139A1, US2008/128139A1, US20080128139 A1, US20080128139A1, US2008128139 A1, US2008128139A1|
|Inventors||Paul W. White|
|Original Assignee||Vetco Gray Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (3), Classifications (6), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This patent application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 11/595,444, filed Nov. 9, 2006, having Attorney Docket No. V2003047A, and entitled Tree Mounted Well Flow Interface Device.
1. Technical Field
The present invention relates in general to subsea wellheads and, in particular, to an improved system, method, and apparatus for a utility skid tree support system for subsea wellheads.
2. Description of the Related Art
In one type of offshore well production, a subsea production tree is installed at the sea floor. The tree may be connected by a flowline jumper to a subsea manifold, which may be connected to other subsea trees in the vicinity. A production riser may extend from the subsea manifold or from an individual tree to a processing facility, normally a floating platform. The well formation pressure is normally sufficient to cause the well fluid to flow up the well to the tree, and from the tree to the processing facility.
In very deep water, the well may have sufficient pressure to cause the well fluid to flow to the tree but not enough to flow from the sea floor to the processing facility. In other cases, the well may even lack sufficient pressure to flow well fluid to the sea floor. Downhole electrical submersible pumps have been used for many years in surface wells, but because of periodic required maintenance, are not normally employed downhole in a subsea well.
A variety of proposals have been made for booster pumps to be installed at the sea floor to boost the well fluid pressure. However, because of the pump size, installation expense and technical difficulties, such installations are rare. When such configurations are used, large utility skids are typically used to move equipment to and from the subsea well from the surface. Utility skids are cumbersome and manipulating them with respect to the well can be very difficult if not hazardous to operators and the well installation itself. Thus, an improved system and method of facilitating interaction between subsea wells and utility skids would be desirable.
Embodiments of a system, method, and apparatus for a utility skid tree support system for subsea wellheads are disclosed. The invention enables a tree to be mounted by and precisely interface with utility skids. Production bore access is provided through an extended production wing block. The system reacts and transfers installation loads and potential snag loads to the conductor. The tree accepts skids for flow boosting, metering, water-oil separation, etc. A conventional choke may be fitted outboard (i.e., downstream) from the utility insert profile.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the present invention, which will become apparent, are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof that are illustrated in the appended drawings which form a part of this specification. It is to be noted, however, that the drawings illustrate only some embodiments of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
A subsea Christmas or production tree 13, such as a horizontal or spool tree, is secured to the upper end of wellhead housing 11 by a conventional connector. Tree 13 has a bore 15 that contains a tubing hanger 17. Tubing hanger 17 supports a string of tubing 19 that extends into the well for the flow of production fluid. Tubing 19 registers with a production passage 21 that extends through tubing hanger 17. A lateral production port 23 extends from production passage 21 through a production master valve 25 within tree 13.
Production passage 21 of tubing hanger 17 has a crown plug profile 31 located above lateral production port 23. Profile 31 is adapted to receive a plug normally lowered and retrieved by a wireline. Tree 13 has a mandrel 33 on its upper end containing an external grooved profile. An adapter 35 lands on tree 13. Adapter 35 has a conventional, hydraulically-actuated connector 37 for connecting to tree mandrel 33. Adapter 35 has a seal sub 39 that extends downward into sealing engagement with production passage 21 in tubing hanger 17. Adapter 35 has a production passage 41 that registers with seal sub 39 for the flow of production fluid. An isolation valve 43 and a retrievable plug 45 are located within production bore 41. A swab valve may be used in lieu of plug 45.
A lateral production port 47 extends from production bore 41 between valve 43 and plug 45. Adapter 35 preferably has a mandrel 49 on its upper end that receives a debris cap 51. Lateral production port 47 connects to an intake conduit 53. A flow interface device 55, such as a subsea pressure intensifier or oil separator, is connected to intake conduit 53, which is preferably shorter than it appears in the drawings.
The device 55, or an outlet conduit extending therefrom (not shown), is connected to a utility skid tree support system 61. In one embodiment, system 61 comprises a wing block 63 having an extended length, a horizontal bore 65 and a vertical bore 71 extending upward therefrom to device 55. The wing block 63 may be mounted to tree 13 as shown on a lip 66, or integrally formed with tree 13 (not shown). Horizontal bore 65 has a production wing valve 67 that is mounted adjacent to and in fluid communication with production master valve 25 and lateral production port 23. Horizontal bore 65 may be interconnected to a choke body 69, which also may comprise a T-conduit or still other equipment.
As best shown in
In one embodiment, a block leg 73 extends downward from wing block 63 directly beneath wing valve 67. Block leg 73 extends across the entire width W of wing block 63, and has a horizontal lower surface 75 and a chamfer 77 as shown. In addition, a wide groove 79 is formed on a top surface 81 of wing block 63. As shown in
Referring again to
In operation, the well would initially be producing with sufficient pressure to flow well fluid to a surface processing facility. In such case, adapter 35, device 55 and its conduit 53 would not be located subsea. Instead, a choke insert (not shown) may be located in choke body 69. An internal tree cap (not shown) would be located at the upper end of tree 13 for sealing bore 15. A plug (not shown) would be located in profile 31. The fluid would flow out through valves 25 and 67, through the choke in choke body 69, and into a production flow line.
If the pressure of the well depletes sufficiently so as to require a booster pump, the operator would then connect a riser (not shown) to tree mandrel 33. The operator closes valves 25, 67, which along with production port 23, make up a main flow path. The operator removes the internal tree cap through the riser while leaving the crown plug within crown profile 31. With the assistance of an ROV, the operator removes the choke insert from choke body 69. The operator then removes the riser and lowers adapter 35, device 55 and its conduit 53 as a unit. Seal sub 39 stabs sealingly into tubing hanger bore 21. Connector 37 connects adapter 35 in place, and device 55 is connected to wing block 63. A downward force due to the weight of device 55 passes through adapter 35 and tree 13 into wellhead housing 11.
The operator reconnects the riser at this time to adapter mandrel 49. With a wireline tool, the operator removes plug 45 from its position above lateral production port 47. The operator opens valve 43 and removes the crown plug from profile 31 and reinstalls plug 45 above production port 47. Alternatively, the crown plug could be re-located from profile 31 to the position above production lateral port 47, thus serving as plug 45. The riser is removed and debris cap 51 is installed on adapter 35.
Opening valve 97 and supplying power to pressure intensifier 109 causes well fluid to be flow from production bore 76 through passage 96, port 101, and conduit 107 to pressure intensifier 109. Pressure intensifier 109 pumps the fluid out conduit 111 through choke body 83 into the flow line. Adapter passage 96, conduits 107, 111 and pressure intensifier 109 thus create a bypass flow path.
Device 55 also may operate in combination with a downhole electrical submersible pump suspended on tubing. If the assembly is to be used as an injection well, device 55 would operate in the reverse direction and fluid would flow from choke body 69 to device 55, which pumps fluid down production passage 21. If device 55 is to be utilized from the beginning, it could be lowered and installed initially along with tree 13. In that instance, a T-conduit would typically be used for choke body 69. For removing device 55 to repair or replace it, the operator attaches a riser, removes plug 45 and lowers a crown plug into crown plug profile 31.
Alternately, plug 45 may be released, lowered and reset in crown plug profile 31. The operator disengages connector device 55 and connector 37 and retrieves the assembly to the surface. The operator then lowers the assembly with a new or repaired device 55 and repeats the process. In addition, the operator has the ability of lowering tools or instruments on wireline or coiled tubing into tubing 19 by removing debris cap 51 and connecting a riser to mandrel 49. Plug 45 is then removed through the riser, providing access for wireline tools.
The invention has significant advantages. Supporting utility skids with a wing block for the tree utilizes the extensive strength of the tree mandrel to avoid the need for specially constructed supporting frames. Equipment such as pump assemblies can be readily installed and retrieved for maintenance. The assembly allows access to the tree tubing and tubing annulus for workover operations. The system reacts and transfers installation loads and potential snag loads to the conductor. The tree accepts skids for flow boosting, metering, water-oil separation, etc.
While the invention has been shown or described in only some 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.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8245787 *||Nov 19, 2008||Aug 21, 2012||Vetco Gray Inc.||Utility skid tree support system for subsea wellhead|
|US20130000918 *||Jun 29, 2011||Jan 3, 2013||Vetco Gray Inc.||Flow module placement between a subsea tree and a tubing hanger spool|
|WO2015009577A1 *||Jul 11, 2014||Jan 22, 2015||Cameron International Corporation||Self-draining production assembly|
|Cooperative Classification||E21B43/121, E21B33/038|
|European Classification||E21B33/038, E21B43/12B|
|Feb 28, 2008||AS||Assignment|
Owner name: VETCO GRAY INC., TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WHITE, PAUL W.;REEL/FRAME:020594/0434
Effective date: 20080213
|Nov 24, 2008||AS||Assignment|
Owner name: VETCO GRAY INC., TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WHITE, PAUL W.;REEL/FRAME:021909/0831
Effective date: 20081119