CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. utility patent application Ser. No. 11/690,373, attorney docket number V2006068, filed on Mar. 23, 2007, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates in general to subsea wellhead equipment, and in particular to a method of simultaneously running an internal tree cap and tubing hanger into a subsea horizontal treehead.

BACKGROUND OF THE INVENTION

A conventional subsea horizontal tree includes a wellhead housing which contains one or more casing hangers, one of which is secured to a string of production casing that extends into the well. A horizontal tree body, also known as a tree or tubing spool or spool tree, mounts to the top of the wellhead housing and seals to it. The horizontal tree body has a central bore axially through it and a horizontal or lateral production flow passage through the wall of the horizontal tree body. A tubing hanger lands and seals in the central bore of the horizontal tree body and is secured to a string of tubing that extends through the production casing hanger and production casing into the well. The tubing hanger has a production bore axially through it that is in fluid communication with the tubing. The tubing hanger also has a lateral flow passage in fluid communication with the tubing hanger production bore and with the lateral production flow passage in the horizontal tree body.

Annular seals are located between the tubing hanger and the central bore of the horizontal tree body above the production flow passage to provide primary, and occasionally, secondary barriers to leakage from the production flow pathways and well bore. Additionally, one or more wireline deployable plugs fit in one or more lockdown profiles in the tubing hanger production bore to provide primary, and occasionally, secondary barriers to leakage from the production and well bores. A tree cap may also fit above the tubing hanger in the central bore of the horizontal tree body. The tree cap may be of an internal or external lockdown configuration. In either case, the tree cap will seal to the central bore of the horizontal tree body and act as an additional barrier to leakage from the well. The tree cap of either configuration may have a vertical bore through it.

Another typical feature of subsea horizontal trees is an annulus and workover passageway that establishes a fluid communication pathway between the annular space around the tubing below the tubing hanger and a space inside the central bore of the horizontal tree body above the tubing hanger. This annulus and workover passageway can be ported through the tubing hanger, through the horizontal tree body or a combination of both. Alternatively, the annulus and workover passageway may be ported entirely out of the tree from a position below the tubing hanger.

In practice, there are generally two horizontal tree configurations: (1) a horizontal tree with a tubing hanger fitted with one or more plugs in its production bore and an internal tree cap, with a plug in its vertical bore; or (2) a horizontal tree with a tubing hanger fitted with at least two plugs in its production bore and eliminating the internal tree cap. This second style of horizontal tree typically utilizes a tree cap that locks externally to the tree body and may or may not include a seal to the tree body. In either tree cap case, the annulus and workover passageway will contain at least two closure members in the form of gate valves, for example.

The primary difference between these two general horizontal tree configurations is that the first has a primary and secondary barrier that employs independent lockdown structures for the two barriers, and the second has a primary and secondary barrier that ultimately rely on the tubing hanger to horizontal tree body lockdown structure. Some operators, and some regulatory authorities believe that the first and second horizontal tree configurations are equivalently safe in operation. Other operators and regulatory authorities believe only the first configuration meets the dual barrier industry philosophies and/or regulatory requirements.

One advantage of the second configuration is that the elimination of the internal tree cap eliminates the need for a second drill pipe run to install it. In running (or working over) the first style of horizontal tree, the tubing hanger is run into the horizontal tree body typically on a hydraulically-actuated running tool that is run on drill pipe. Afterwards, the internal tree cap is run into the horizontal tree body typically on the same hydraulically-actuated running tool, or one very similar, on drill pipe. This results in two drill pipe trips to the seafloor.

In running (or working over) the second style of horizontal tree, the tubing hanger is run into the horizontal tree body typically on the hydraulically-actuated running tool on drill pipe. Afterwards, a lower plug is run on wireline and landed, locked and sealed to the production bore of the tubing hanger and then an upper plug is run on wireline and landed, locked and sealed to the production bore above the first plug. In deeper water wells, this results in potentially significant rig time savings. However, it comes with the compromise that the two plugs rely on the single tubing hanger lockdown mechanism to ensure that the tubing string assembly does not part from the tree and cause potentially significant leakage of the well bore to the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary cross sectional illustration of an exemplary embodiment of a tubing hanger and internal tree cap assembly.

FIG. 2 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 1 during assembly.

FIG. 3 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 2 during further assembly.

FIG. 4 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 3 during placement of the assembly within an end of a treehead.

FIG. 5 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 4 during operation of the assembly to connect the tubing hanger to the treehead.

FIG. 6 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 5 during operation of the assembly to connect the internal tree cap to the treehead.

FIG. 7 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 6 during operation of the assembly to unlock the running tool from the internal tree cap.

FIG. 8 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 7 during operation of the assembly to remove the running tool from the treehead.

FIG. 9 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 8 during operation of the assembly to position crown plugs within the internal tree cap and the tubing hanger.

FIG. 10 is a fragmentary cross sectional illustration of the tubing hanger and internal tree cap assembly of FIG. 9 during operation of the assembly to remove the crown plugs and the internal tree cap from the treehead.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.

Referring to FIG. 1, a tubing hanger and internal tree cap assembly 100 includes a tubing hanger 102 that defines an internal passage 102a and a radial passage 102b and includes an internal annular recess 102c, an internal annular recess 102d at one end, an external annular recess 102e, an external annular recess 102f, an external annular recess 102g, an external annular recess 102h, an external annular recess 102i, an external annular recess 102j, and internal threaded portion 102k at one end.

A tubular locking ring retainer 104 defines a window 104a and includes a tapered external shoulder 104b that mates with and is supported on the annular external recess 102e of the tubing hanger 102 and an internal annular recess 104c. A conventional split locking ring 106 is received within the window 104a of the locking ring retainer 104 and includes a profiled external surface 106a and a tapered internal surface 106b. An end of a sleeve 108 is mates with and is supported on the external annular recess 102g of the tubing hanger 102 and another end of the sleeve mates with and is supported on the external annular recess 102h of the tubing hanger 102.

A tubing hanger support 110 defines a radial passage 110a that is operably coupled to the radial passage 102b of the tubing hanger 102 and includes an internal annular recess 110b at one end that mates with an end of the sleeve 108, an internal flange 110c that mates with and is received within the external annular recess 102h of the tubing hanger, an internal annular recess 110d that mates with the external annular recess 102i of the tubing hanger, an internal flange 110e that mates with and is received within the external annular recess 102i of the tubing hanger, an external flange 110f, an external annular recess 110g, and an internal profiled annular recess 110h. An energizing ring 112 includes a tapered external annular recess 112a at one end, internal grooves 112b at one end, an internal annular recess 112c that mates with an receives a portion of the tubing hanger support 110, an internal annular recess 112d that mates with and receives the external flange 110f of the tubing hanger support, a tapered internal annular recess 112e, and an internal annular recess 112f.

A lower end of a tubular support member 114 is positioned in opposing relation to an upper end of the tubing hanger support 110 and includes an internal annular recess 114a, an external annular recess 114b, an external threaded portion 114c at an upper end, and an external threaded portion 114d at the upper end. A tubular support member 116 includes a tapered internal annular recess 116a at one end, an internal threaded portion 116b at another end that engages the external threaded portion 114c of the tubular support member 114, a tapered external annular recess 116c at the other end, an external annular recess 116d, an external annular recess 116e, and an external annular recess 116f that mates with an upper end of the energizing ring 112. A snap ring 118 is at least partially received within the external annular recess 116e of the tubular support member 116 and the internal annular recess 112f of the energizing ring 112. In this manner, the snap ring 118 releasably holds the upper end of the energizing ring 112 within the external annular recess external annular recess 116f of the tubular support member 116.

An upper end 120a of a locking dog 120 is retained within the external annular recess 114b of the tubular support member 114 by the tapered internal annular recess 116a of the tubular support member 116 and a lower end 120b of the locking dog is retained within the external annular recess 110g of the tubing hanger support 110 by the energizing ring 112. A tubular support 122 defines a window 122a and includes an internal threaded portion 122b at one end that is coupled to an external threaded portion 102k of the tubing hanger 102. An upper end 124a of a latch dog 124 is retained within the internal annular recess 114a of the tubular support member 114 by the upper portion of the tubular support 122 and a lower end 124b of the latch dog mates with and is received within the internal annular recess 110h of the tubing hanger support 110. In an exemplary embodiment, the locking dog 120 and the latch dog 124, either alone or in combination, provide a linking assembly for linking the internal tree cap 126 and the tubing hanger 102. Furthermore, in an exemplary embodiment, as a result, the internal tree cap 126 supports the weight on the tubing hanger 102.

An internal tree cap 126 includes an external annular recess 126a at one end, a channel 126b at one end that receives and mates with the upper ends of the tubular support member 114 and the tubular support member 116, an internal tapered annular recess 126c at one end that mates with and receives an upper end of the tubular support 122, an internal annular recess 126d, an internal profiled annular recess 126e, an channel 126e, an external annular recess 126f, an external annular recess 126g, an external annular recess 126h, an external annular recess 126i at another end, an internal annular recess 126j at another end, and an external tapered annular recess 126k at a lower end. A sleeve 128 includes an external ribbed surface 128a at one end, an internal annular recess 128b at one end, and another end that mates with and is received within the external annular recess 126h of the internal tree cap 126. A tubular support member 130 includes an internal annular recess 130a at one end that mates with and receives an upper end of the sleeve 128, an internal annular recess 130b that mates with and is received within the external annular recess 126h of the internal tree cap 126, another end that mates with and is received within the external annular recess 126i of the internal tree cap 126, an external annular recess 130c, an external flange 130d, and an external flange 130e that defines a longitudinal passage 130f therethrough.

An energizing ring 132 that includes an internal profiled annular recess 132a, an internal annular recess 132b that receives and mates with the external flange 130e of the tubular support member 130, an internal annular recess 132c that receives and mates with a lower end of the tubular support member 130, an external tapered external annular recess 132d at another end, and an internal ribbed surface 132e at another end, mates with and receives the sleeve 128. A conventional split locking ring 134 is received within the external annular recesses, 126f and 126g, of the internal tree cap 126, and includes a profiled external surface 134a and a tapered internal surface 134b.

An upper tubular running tool 136 that defines a radial passage 136a at one end and a longitudinal passage 136b that depends therefrom and extends to another end, and includes a tapered external annular recess 136c and an internal annular recess 136d at the other end is received within an mates with the internal tree cap 126. A lower tubular running tool 138 that defines a longitudinal passage 138a that is and a radial passage 138b that extends therefrom and includes a tapered external flange 138d that is received within and mates with the internal annular recess 126d of the internal tree cap 126, and an external annular recess 138e that receives and mates with the tubing hanger 102 includes an upper end that mates with and is received within a lower end of the upper tubular running tool 136. A tubular conduit 140 extends between and operably couples opposing ends of the passageways, 136b and 138a, of the upper and lower tubular running tools, 136 and 138, respectively. A tool finger 142 is pivotally coupled to an outer surface of the lower tubular running tool 138 proximate the external flange 138d for pivotal movement relative thereto.

Referring now to FIG. 2, in an exemplary embodiment, the upper tubular running tool 136 is then displaced in the direction of the lower tubular running tool 138. As a result, the external tapered annular recess 136c of the upper tubular running tool 136 is displaced into engagement with the tool finger 142 thereby pivoting the tool finger outwardly in a radial direction and into the profiled internal annular recess 126e of the internal tree cap 126 thereby locking the internal tree cap to the lower tubular running tool 138. Furthermore, as a result, the internal annular recess 136d of the upper tubular running tool is displaced into engagement with the upper end of the lower tubular running tool 138 thereby displacing the conduit 140 into the upper end of the longitudinal passage 138a of the lower tubular running tool.

Referring now to FIG. 3, in an exemplary embodiment, a universal running tool 200 is then coupled to the assembly 100 that includes an inner sleeve 202 that defines a longitudinal passage 202a and a radial passage 202b that depends therefrom and includes an internal annular recess 202c at one end. At least a portion of an upper end of the upper tubular running tool 136 is received within and mates with a lower portion of the inner sleeve 202. An inner sleeve 204 that defines a radial passage 204a is received within and mates with the internal annular recess 202c of the inner sleeve 202, receives and mates with the upper tubular running tool 136, and is received within and mates with the internal annular recess 126j of the internal tree cap 126.

An internal sleeve 206 that defines an internal annular recess 206a receives and mates with the inner sleeve 202 and is received within and mates with the internal annular recess 132b of the energizing ring 132. An internal sleeve 208 is received within and mates with the internal annular recess 206a of the internal sleeve. An internal sleeve 210 is coupled to an end of the inner sleeve 202 and positioned within the annular recess 206a of the internal sleeve 206 and an end of the internal sleeve 210 is received within and mates with the external annular recess 130c of the tubular support member 130. An outer sleeve 212 that defines an internal annular recess 212a and an internal annular recess 212b receives and mates with the inner sleeve 206. An upper end 214a of a latch 214 is received within the internal annular recess 212a of the outer sleeve 212 and a lower end 214b of the latch is received within the internal annular recess 132a of the energizing ring 132.

An upper end 216a of a locking sleeve 216 is received within and mates with the internal annular recess 206a of the inner sleeve 206 and is positioned proximate a lower end of the internal sleeve 208 and above at least a portion of the internal sleeve 210 and a lower end 216b of the locking sleeve 216 is received within and mates with the internal annular recess 206a of the inner sleeve 206 and is positioned below at least a portion of the internal sleeve 210. In this manner, the universal running tool 200 is locked to the internal tree cap 126.

Referring now to FIG. 4, in an exemplary embodiment, the coupled assemblies, 100 and 200, are then run into an open end of a conventional treehead 300 that includes an upper profiled internal annular recess 302, an internal load shoulder 304, a lower profiled internal annular recess 306, and an internal load shoulder 308. In particular, the coupled assemblies, 100 and 200, are then run into an open end of the treehead 300 until the external tapered annular recess 126k of the internal tree cap 126 lands on the internal load shoulder 304 of the treehead 300 and the tapered external shoulder 104b of the locking ring retainer 104 lands on the internal load should 308 of the treehead.

Referring now to FIG. 5, in an exemplary embodiment, a pump 400 is then operated to inject a fluidic material into and through the passage 202a of the sleeve 200. As a result, fluidic material is then conveyed into and through the passages, 204a, 136a, 136b, the conduit 140, and the passages 138a, 138b, 102b, and 110g. As a result, the energizing ring 112 is displaced downwardly into engagement with the locking ring 106. As a result, the interaction of the tapered external annular recess 112a of the energizing ring 112 with the tapered internal surface 106b of the locking ring 106 causes the locking ring to be displaced outwardly in a radial direction into engagement with the profiled internal recess 306 of the treehead 300.

Furthermore, the downward displacement of the energizing ring 112 also moves the energizing ring out of engagement with the lower end 120b of the a locking dog 120. As a result, the lower end 120b of the locking dog 120 may pivot outwardly out of engagement with the external annular recess 110g of the tubing hanger support 110.

Referring now to FIG. 6, in an exemplary embodiment, the outer sleeve of the assembly 200 is displaced downwardly thereby causing the energizing ring 132 to be displaced downwardly. As a result, the interaction of the tapered external annular recess 132d of the energizing ring 132 with the tapered internal surface 134b of the locking ring 134 causes the locking ring to be displaced outwardly in a radial direction into engagement with the profiled internal recess 302 of the treehead 300 thereby locking the internal tree cap 126 to the treehead 300. In an exemplary embodiment, as a result, the internal tree cap 126 then at least partially supports the weight of the tubing hanger 102 and the upper and lower tubular running tools, 136 and 138.

Referring now to FIG. 7, in an exemplary embodiment, the upper tubular running tool 136 is then displaced upwardly relative to the lower tubular running tool 138. As a result, the external tapered annular recess 136c of the upper tubular running tool 136 is moved out of engagement with the tool finger 142. As a result, the tool finger 142 may pivot out of engagement with the internal annular recess 126e of the internal tree cap 126 thereby unlocking the internal tree cap from the lower tubular running tool 138.

Referring now to FIG. 8, in an exemplary embodiment, the upper and lower tubular running tools, 136 and 138, are then removed. As a result, the lower end 124b of the latch dog 124 may pivot out engagement with the internal annular recess 110h of the tubing hanger support 110.

Referring now to FIG. 9, in an exemplary embodiment, conventional crown plugs, 500a and 500b, may then be coupled to the profiled internal annular recesses, 126e and 102c, of the internal tree cap 126 and the tubing hanger 102, respectively, in a conventional manner.

Referring now to FIG. 10, in an exemplary embodiment, the crown plugs, 500a and 500b, may then be decoupled from the profiled internal annular recesses, 126e and 102c, of the internal tree cap 126 and the tubing hanger 102, respectively, in a conventional manner. In an exemplary embodiment, the energizing ring 132 may then be displaced upwardly relative to the locking ring 134 thereby decoupling the locking ring from the profiled inner annular recess 302 of the treehead 300. As a result, the internal tree cap 126 is no longer locked to the treehead 300. In an exemplary embodiment, the assembly 200 may then be displaced upwardly relative to the treehead 300. As a result, the tubular support member 114, the tubular support member 116, the locking dog 120, the tubular support 122, the latch dog 124, the internal tree cap 126, the sleeve 128, the tubular support member 130, the energizing ring 132, and the locking ring 134 are also displaced upwardly out of the treehead 300 and out of engagement with the tubing hanger 102.

It is understood that variations may be made in the above without departing from the scope of the invention. For example, the teachings of the exemplary embodiments may also be used to complete a wellhead, treehead, or other equivalent structure. While specific embodiments have been shown and described, modifications can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments as described are exemplary only and are not limiting. Many variations and modifications are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.