Patent Grant
11401768
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/NO2019/050076, filed on Apr. 10, 2019 and which claims benefit to Norwegian Patent Application No. 20180488, filed on Apr. 10, 2018. The International Application was published in English on Oct. 17, 2019 as WO 2019/199177 A1 under PCT Article 21(2).
The present invention relates to a method of and to a system for providing hydraulic and/or electrical connections to a tubing hanger installed on a wellhead.
It is known to mount a tubing hanger on the wellhead during the drilling of a wellbore for oil and/or gas production or during the completion process for bringing the wellbore into production. The tubing hanger is typically mounted in a production adapter base or in a tubing head spool which is mounted on the wellhead. The tubing hanger is provided to support the production tubing string.
A schematic illustration of an example of a prior art system 10 for landing a tubing hanger on a subsea wellhead is illustrated in
To install the tubing hanger 12, the tubing hanger 12 is typically mounted on a tubing hanger running tool 14 which is suspended from a drill string 20 via a shear joint 16, and a crossover 18. The shear joint 16 is a portion of tubular which is capable of being sheared using a ram-type BOP 36. The drill string 20 is lowered down a riser 22 which extends from a drilling rig 24 to a blowout preventer (BOP) stack 34 mounted on a production adapter base 32 (also known as a tubing hanger spool) on top of the wellhead 28, until the tubing hanger 12 is landed in the internal profile of the production adapter base 32, and the shear joint 16 is aligned with a ram-type BOP 36 in the blowout preventer (BOP) stack 34. In an emergency situation, the ram-type BOP 36 can be operated to sever the drill string 20 and release the tubing hanger 12 and tubing hanger running tool 14, the ram-type BOP 36 thereby sealing the well bore and allowing the drill string 20 to be withdrawn from the riser 22.
It is known to provide the tubing hanger 12 with ports for hydraulic and electrical connection to the surface when the tubing hanger 12 is mounted on a subsea wellhead 28. The electrical connections may, for example, be used to provide power to electrical sensors mounted on the tubing hanger 12. The hydraulic connections may provide means for operating downhole safety valves or may provide a port for the injection of chemicals into the wellbore. These ports are connected to an electrohydraulic umbilical 26 via the internal crossover 18, shear joint 16, and tubing hanger running tool 14. Each of the internal crossover 18, shear joint 16, and the tubing hanger running tool 14 includes passages for the hydraulic and electric connections which, when these parts are mounted on the drill string 20, extend generally parallel to the drill string 20. Stab connections are provided to connect the corresponding passages in adjacent parts.
The various electrical and hydraulic connectors in the umbilical 26 are connected to the passages in the crossover 18 on the drilling rig 24 before the drill string 20 is lowered into the riser. The umbilical 26 is periodically clamped to the drill string 20 as the drill string 20 is lowered. This process is relatively time consuming; clamping the umbilical 26 to the drill string 20 can add approximately 12 hours to the time taken to install the tubing hanger 12, and the process of unclamping the umbilical 26 can take a further 12 hours of rig time during the recovery process.
An aspect of the present invention is to provide an improved system for and a method of providing connections to a tubing hanger mounted on a subsea wellhead.
In an embodiment, the present invention provides a method of connecting a tubing hanger mounted in a subsea wellhead to equipment which is external to the tubing hanger. The method includes securing the tubing hanger to an end of a drill string using a tubing hanger running tool assembly, lowering the drill string from a drilling rig so as to land the tubing hanger on or in the wellhead, running an umbilical from the sea surface to the wellhead, and connecting the umbilical to at least one conduit in the tubing hanger via the tubing hanger running tool assembly. The umbilical is unconnected to the drill string other than via the tubing hanger running tool assembly.
The present invention is described in greater detail below on the basis of embodiments and of the drawings in which:
A first aspect of the present invention provides a method of connecting a tubing hanger mounted on a subsea wellhead to equipment external to the tubing hanger, the method comprising:
In an embodiment of the present invention, the drill string can, for example, be lowered to the wellhead inside a riser, the riser extending upwardly from a subsea wellhead to the drilling rig, and the umbilical is run to the wellhead outside the riser. The riser may extend upwards from a blowout preventer stack to the drilling rig.
The umbilical may be connected to the tubing hanger running tool assembly via an external connector which is connected to an external surface of the tubing hanger running tool assembly.
An end of the umbilical may be connected to a subsea umbilical termination assembly at or above sea level, with the subsea umbilical termination assembly being lowered on a cable to the seabed with the umbilical connected thereto until the subsea umbilical termination assembly comes to rest on the seabed. In this case, the subsea termination assembly may be connected to the external connector via at least one electrical or hydraulic flying lead.
The or each flying lead may be connected to the external connector using a remotely operated vehicle.
The umbilical may be lowered to the wellhead from the drilling rig. The umbilical may alternatively be lowered to the wellhead from a separate vessel.
The tubing hanger running tool assembly may have a first end which has the tubing hanger releasably suspended therefrom, a second end which is connected to the drill string, an end face at its first end, and a radially outward facing surface which extends generally perpendicular to the end face, wherein the tubing hanger running tool assembly is further provided with a conduit which extends from the end face to the radially outward facing surface, and which is connected to a corresponding conduit in the tubing hanger.
The tubing hanger running tool assembly may include a tubing hanger running tool at its first end, and a separate crossover part at its second end, the conduits extending from the end face of the tubing hanger running tool to the radially outward facing surface of the crossover part. The conduit in the tubing hanger running tool assembly is in this case formed by a conduit portion in the tubing hanger running tool and a conduit portion in the crossover part, the conduit portions being connected by stab connectors.
The tubing hanger running tool assembly and tubing hanger may be provided with a plurality of such conduits.
The conduit or at least one of the conduits may comprise a passage along which a flow of fluid is permitted.
The conduit or at least one of the conduits may comprise an electrical line.
The method may further comprise, prior to landing the tubing hanger in or on the wellhead, mounting on the wellhead a separate external crossover part which is generally tubular and which has a radially inward facing surface which encloses a generally central space, a radially outward facing surface, and a passage which extends from the radially outward facing surface to the radially inward facing surface, and when lowering the drill string to land the tubing hanger in or on the wellhead, passing the tubing hanger through the generally central space of the external crossover part, and when the tubing hanger is landed in or on the wellhead, aligning the or each conduit emerging from the radially outward facing surface of the tubing hanger assembly with the passage in the external crossover part.
The external connector may be inserted into the passage of the external crossover part from outside the external crossover part to provide an electrical or fluid tight connection to the or each conduit in the tubing hanger running tool assembly.
The external connector may be mounted on the external crossover part before the external crossover part is mounted on the wellhead.
A blowout preventer stack may be mounted on top of the external crossover part.
The tubing hanger may be landed in a tubing hanger support part, which is known as a production adapter base, a tubing hanger spool, or a tubing head spool, which is mounted on top of and secured to the wellhead. Where an external crossover part is used, the external crossover part may be mounted on top of the tubing hanger support part.
A second aspect of the present invention provides a system for providing connections to a tubing hanger mounted in a subsea wellhead, the system comprising a tubing hanger running tool assembly having a first end which is configured to have a tubing hanger releasably suspended therefrom, an end face at its first end, and a radially outward facing surface which extends generally perpendicular to the end face, wherein the tubing hanger running tool assembly is further provided with at least one conduit which extends from the end face to the radially outward facing surface.
In an embodiment, the tubing hanger running tool assembly can, for example, include a tubing hanger running tool at its first end, and a separate crossover part which is at a second end of the assembly, the conduit extending from the end face of the tubing hanger running tool to the radially outward facing surface of the crossover part. The conduit may in this case be formed by a conduit portion in the tubing hanger running tool and a conduit portion in the crossover part, the conduit portions being connected by stab connectors.
The tubing hanger running tool assembly may be provided with a plurality of such conduits.
The conduit or at least one of the conduits may comprise a passage along which a flow of fluid is permitted.
The conduit or at least one of the conduits may comprise an electrical line.
The system may further comprise a separate external crossover part which is generally tubular and which has a radially inward facing surface which encloses a generally central space and a radially outward facing surface, and a passage which extends from the radially outward facing surface to the radially inward facing surface, wherein the external crossover part is sized relative to the tubing hanger running tool assembly so that the tubing hanger running tool assembly fits into the generally central space with the or each conduit emerging from the radially outward facing surface of the tubing hanger assembly into the passage.
The system may further comprise a connector which is adapted to be inserted into the passage of the external crossover part from outside the external crossover part to provide an electrical or fluid tight connection to the conduits in the tubing hanger running tool assembly.
The system may further comprise an umbilical via which the conduits can be connected to surface equipment. The system may in this case further comprise an umbilical termination assembly which is adapted to be connected to the umbilical, and to the connector via one or more flying hydraulic or electrical flying leads.
Embodiments of the present invention will be described below under reference to the drawings.
Referring now to
The tubing hanger 12 is mounted on a lowermost end of a drill string 20 via the internal crossover 18′ and the tubing hanger running tool 14. The drill string 20 extends down from a drilling rig 24 into a riser 22, the riser 22 extending from the drilling rig 24 to a blowout preventer (BOP) stack 34 which is mounted on top of the production adapter base 32 via a second crossover part 38, which is hereinafter referred to as the external crossover 38. The blowout preventer (BOP) stack 34 has a main passage with a longitudinal axis which is generally aligned with a longitudinal axis of the drill string 20, and includes at least one ram-type BOP 36 which is aligned with the drill string 20 above the internal crossover 18′.
The tubing hanger 12 and the tubing hanger running tool 14 are of conventional construction and each include at least one conduit via which a hydraulic or electrical connection can be made between the tubing hanger 12 and external equipment. It is typically required to provide a plurality of both hydraulic and electrical connections to the tubing hanger for the reasons discussed in the introduction above. In an embodiment of the present invention, a plurality of such conduits can, for example, be provided, some providing electrical connectivity and some providing hydraulic connectivity.
The tubing hanger 12 is conventionally suspended from a lowermost end of the tubing hanger running tool 14.
As is conventional, each conduit in the tubing hanger 12 is connected to a corresponding conduit in the tubing hanger running tool 14, in this example, via a stab connection. These connections are made in adjacent faces of the tubing hanger 12 and tubing hanger running tool 14 which extend generally perpendicular to the longitudinal axis of the blowout preventer (BOP) stack 34, i.e., the face at the uppermost end of the tubing hanger 12 and the face at the lowermost end of the tubing hanger running tool 14.
Each conduit in the tubing hanger running tool 14 is connected to a corresponding conduit 19 in the internal crossover 18′, in this example, also by a stab connection. These connections are made in adjacent faces of the tubing hanger running tool 14 and internal crossover 18′ which extend generally perpendicular to the longitudinal axis of the blowout preventer (BOP) stack 34, i.e., the face at the uppermost end of the tubing hanger running tool 14 and the face at the lowermost end of the internal crossover 18′.
The internal crossover 18′ is illustrated in greater detail in
The internal crossover 18′ differs from the conventional crossover 18 used in the prior art system described above in that the conduits 19 therein extend from the lowermost end face 18a, before turning through approximately 90° (depending on the exact angle between the lowermost end face 18a and the side wall 18c) to reach the side wall 18c.
The external crossover 38 is tubular and has two ends, and a radially inward facing surface 38a and a radially outward facing surface 38b which extend between the two ends. The system is arranged so that when the tubing hanger 12 is landed in the production adapter base 32, the internal crossover 18′ is located in the space enclosed by the external crossover 38.
The external crossover has a passage 38c which extends radially from the radially inward facing surface 38a to the radially outward facing surface 38b, and which is positioned so that the ends of the conduits 19 in the side wall 18c of the internal crossover 18′ are aligned with the passage 38c in the external crossover 38. This means that the conduits in the tubing hanger 12 can be connected to the exterior of the external crossover 38 via the conduits 19 in the internal crossover 18′ and the conduits in the tubing hanger running tool 14.
It will be appreciated that each conduit could comprise a passage or bore along which a flow of fluid is permitted, or it could comprise an electrical line.
The system is further provided with an umbilical 26 which is used to connect the conduits in the tubing hanger 12 with the appropriate external equipment. The umbilical 26 is of conventional construction and includes the required number of hydraulic and/or electrical lines to mate with the conduits in the tubing hanger 12.
A first end of the umbilical 26 is located above sea level, whilst a second end of the umbilical 26 is connected, by conventional means, to a subsea umbilical termination assembly 40, hereinafter referred to as SUTA 40, which rests on the seabed 30. The SUTA 40 has ROV panels with multi quick connection plates and electrical connector interface (sockets) via which the hydraulic and electrical lines in the umbilical 26 may be connected to hydraulic and electrical flying leads.
The SUTA 40 is connected to the conduits 19 in the internal crossover 18′ by hydraulic and/or electrical flying leads 42 and an external connector 44. As illustrated in
In this example, the external connector 44 is generally cylindrical, having a longitudinal axis which is arranged generally perpendicular to the longitudinal axis of the blowout preventer (BOP) stack 34. It also has a radially outwardly extending flange 44a via which the external connector 44 may be secured, using a plurality of bolts 48, to the radially outward facing surface 38b of the external crossover 38 around the passage 38c, as illustrated in
By utilizing the inventive system, the tubing hanger 12 may be installed in the production adapter base 32 as follows.
The external connector 44 is secured to the external crossover 38, using the bolts 48, at the surface, either on the drilling rig 24 or on a separate vessel 50. At this point, the stab connectors 44b in the external connector 44 are retracted so that they extend only into the passage 38c of the external connector 44, and not into the volume enclosed by the radially inward facing surface 38a.
The external crossover 38 is then mounted on top of the production adapter base 32, the blowout preventer (BOP) stack 34 is secured on top of the external crossover 38, and the lowermost end of the riser 22 secured to the top of the blowout preventer (BOP) stack 34. The tubing hanger 12 is mounted on the end of the drill string 20 via the tubing hanger running tool 14 and the internal crossover 18′, and the drill string 20 is lowered into the riser 22 from the drilling rig 24 until the tubing hanger 12 is landed in the production adapter base 32. The production adapter base 32 is provided with a shoulder on which the tubing hanger 12 comes to rest. The shoulder is in the form of a helix (single or double helix) which assists in providing that the conduits 19 are aligned with the passage 38c in the external connector 38 when the tubing hanger 12 comes to a rest. The stab connectors 44b in the external connector 44 can then be extended along the passage in the external connector 44 to engage with the conduits 19 in the internal crossover 18′ as illustrated in
This is performed without clamping the umbilical 26 to drill string 20 so that a weaker drill string 20 may be used with than in the prior art method discussed above. This weaker drill string 20 can be severed by operating a ram-type BOP 36 in the blowout preventer (BOP) stack 34. It is therefore not necessary to provide a shear joint 16 between the internal crossover 18 and the tubing hanger running tool 14 as in the prior art arrangement illustrated in
Avoiding the need to clamp the umbilical 26 to the drill string 20 may also significantly decrease the time taken to land the tubing hanger 12 in the production adapter base 32, which has significant cost benefits, as well as reducing the amount of activity in the moon pool during the installation procedure, which improves the safety of the procedure. Finally, in the prior art process, there is a risk that one or more of the clamps used to secure the umbilical 26 to the drill string 20 may fall into the well bore, and would need to be retrieved, thus adding to the installation time, and cost, of the procedure. This problem is avoided by using the inventive system.
The umbilical 26 is connected to the SUTA 40 above sea level, and the SUTA 40 is suspended from a cable, to which the umbilical is clamped, and lowered to the seabed 30 using a conventional “Launch and Recovery System” which comprises a winch, a heave compensator, and an umbilical reel 46. When the SUTA 40 is in place, the connections between the SUTA 40 and the external crossover are made using at least one remotely operated vehicle (ROV), which secures the external connector 44 to the SUTA 40 via the appropriate number of hydraulic or electrical flying leads to provide the desired number and type of connections from surface to the tubing hanger.
The inventive system therefore separates the procedure of landing the tubing hanger 12 in the production adapter base 32 from the process of making the electrical and/or hydraulic connections to the tubing hanger 12 so that the two processes can be carried out simultaneously or at different times, depending on what fits in best with the overall completion process.
The launch and recovery system may be mounted on the drilling rig 24 as illustrated in
The present invention is not limited to embodiments described herein; reference should be had to the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20180488 | Apr 2018 | NO | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NO2019/050076 | 4/10/2019 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2019/199177 | 10/17/2019 | WO | A |
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