Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2000-08-31
2002-11-26
Vidovich, Gregory M. (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S558000, C029S416000, C285S003000
Reexamination Certificate
active
06484382
ABSTRACT:
REFERENCE TO MICROFICHE APPENDIX
This application is not referenced in any Microfiche Appendix.
BACKGROUND OF THE INVENTION
This invention is concerned with a method of providing an internal circumferential shoulder in a cylindrical passageway and is exemplified by an installable load shoulder for a tubing or casing head, that is also frequently called a “wellhead”. “Tubing” or “casing” as used herein is inclusive of tubular products as used in drilling and completing oil and/or gas wells. The invention is particularly concerned with, but not limited to, an installable load shoulder positioned in a wellhead to support a tubing hanger or a casing hanger.
When a well is drilled into the earth it is customary to attach at the upper end of the well, such as at the upper end of surface casing, a wellhead which provides the super-structure for supporting smaller diameter tubular strings, whether strings of casing or strings of tubing. For this purpose a hanger is employed, either a casing hanger or a tubing hanger as the case may be that is secured to the upper end of a string of pipe—that is, a string of casing or a string of tubing. Within the wellhead means must be provided for removably supporting the hanger and for this purpose it is customary to provide in the wellhead a circumferential load shoulder. A removable hanger, having casing or tubing suspended therefrom, is rested on the load shoulder. One problem with this arrangement is that the provision of an internally extending circumferential ledge within the interior of a wellhead reduces the internal diameter of the wellhead and thereby limits the diameter of drill bits or other tools or implements that may thereafter be inserted through the wellhead. The invention herein is an installable load shoulder that provides means for supporting a hanger, either a tubing hanger or a casing hanger within the wellhead and in a manner that the internal diameter of the wellhead is maximized. That is, a wellhead, having a full internal diameter opening therethrough can be equipped with a load shoulder that provides an inwardly protruding circumferential ledge on which a tubing or casing hanger can be supported and the installable load shoulder makes it possible to maintain a larger wellhead minimum internal diameter.
The concept of utilizing an installable load shoulder in a wellhead to support a tubing or a casing hanger is illustrated and described in U.S. Pat. No. 5,984,008 that issued on Nov. 16, 1999, entitled: “INSTALLABLE LOAD SHOULDER FOR USE IN A WELLHEAD TO SUPPORT A TUBING HANGER”. U.S. Pat. No. 5,984,008 is incorporated herein by reference and is a source of background information to the type of invention to which the present disclosure pertains. For further background information reference can be had to the following previously issued U.S. Patents:
PATENT NO.
INVENTOR
TITLE
2,086,431
Penick et al.
Tubing Head
2,328,840
O'Leary
Linear Hanger
3,341,227
Pierce, Jr.
Casing Hanger
3,893,717
Nelson
Well Casing Hanger
Assembly
3,918,747
Putch
Well Suspension System
4,167,970
Cowan
Hanger Apparatus for
Suspending Pipes
4,515,400
Smith et al.
Wellhead Assembly
4,528,738
Galle, Jr.
Dual Ring Casing Hanger
4,534,583
Milberger et al.
Mudline Casing Hanger
Assembly
4,550,782
Lawson
Method and Apparatus for
Independent Support of Well
Pipe Hangers
4,641,708
Wightman
Casing Hanger Locking
Device
4,651,830
Crotwell
Marine Wellhead Structure
4,751,968
Ames et al.
Wellhead Stabilizing Member
with Deflecting Ribs
4,770,249
Courtney
Method and Apparatus for
Reduction of Well Assembly
Time
4,903,992
Jennings et al.
Locking Ring for Oilwell
Tool
5,026,097
Reimert
Wellhead Apparatus
5,060,985
Seaton
Location of Tubular Members
5,209,521
Osburne
Expanding Load Shoulder
5,259,459
Valka
Subsea Wellhead Tieback
Connector
5,327,965
Stephen et al.
Wellhead Completion System
5,984,008
Lang et al.
Installable Load Shoulder for
Use in a Wellhead to Support
a Tubing Hanger
BRIEF DESCRIPTION OF THE INVENTION
This invention is a method of providing an internal circumferential shoulder in a cylindrical passageway and will be described and illustrated as the invention is employed to provide a wellhead installable load shoulder.
A wellhead is a metallic device affixed to the upper end of surface casing of an oil or gas well that is employed to suspend casing and/or tubing in the well. More specifically, a wellhead functions to provide the super-structure for suspending the upper end of a string of casing or tubing that extends from the earth's surface down into a bore hole. In addition to providing the structures to support the weight of strings of tubing or casing, a wellhead functions to close off the upper end portion of casing or tubing and to provide communication as necessary with equipment whereby oil or gas produced by the well can be safely conveyed for refining and/or use without leakage to the environment.
Wellheads provide a vertical opening down which strings of tubing or casing or tools, such as drill bits can be inserted. The most typical construction of a wellhead employs the arrangement wherein the vertical cylindrical opening has two internal diameters—that is, a lower reduced internal diameter and an upper enlarged internal diameter, the differences in diameters providing an integral, circumferential ledge or shoulder that is used to support a tubing or casing hanger. The maximum diameter of any device passing through the typical wellhead is limited to the smaller diameter lower portion of the wellhead vertical opening that defines the load shoulder. One way of providing a larger diameter passageway is to make the load shoulder a separate element. In this way an internal circumferential groove is provided in the opening through the wellhead and a load shoulder can then be inserted into the groove to support a casing or tubing hanger when required. An example of an installable load shoulder for use in a wellhead is U.S. Pat. No. 5,984,008 entitled, “INSTALLABLE LOAD SHOULDER FOR USE IN A WELLHEAD TO SUPPORT A TUBING HANGER”. As previously stated, this patent is incorporated herein by reference. In this patent, a wellhead is provided with an internal circumferential groove and an integral toroidal member functions as an installable load shoulder. The integral toroidal member has a split therein that defines opposed first and second ends. The integral toroidal load shoulder can be collapsed so that the ends move toward each other providing an external diameter that is less than the internal diameter of the opening through the wellhead. When the circumferentially collapsed toroidal member is moved downwardly within the opening through the wellhead to the location of the enlarged internal diameter circumferential groove, the toroidal member can then resiliently expand to an increased external diameter within the circumferential groove. The end surfaces moving apart from each other so that the integral toroidal member is thereby seated within the circumferential groove. The toroidal member is configured so that when seated it extends circumferentially within the borehole opening and thereby provides a circumferential surface on which a tubing or casing hanger can be seated.
The present invention provides a load shoulder that accomplishes the same basic function as the installable load shoulder of U.S. Pat. No. 5,984,008 but has a completely different structural arrangement and is installed in the interior of a wellhead in a completely different way.
The present invention includes a toroidal member manufactured to have a predetermined radial cross-sectional configuration dimensioned to fit within an internal circumferential groove in a wellhead. After the toroidal member is manufactured with the predetermined cross-sectional shape, it is cut into at least three segments. In one embodiment, two spaced apart holes are first drilled and then tapped to provide internally threaded holes. The axes of the tapped holes are parallel to the toroidal member toroidal axis. After the holes are drilled and threaded, the integral toroidal member is cut
ERC Industries, Inc.
Head Johnson & Kachigian
Jimenez Marc
Vidovich Gregory M.
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