A FLOWLINE WITH A METAL SEAL AFTER HOT TAPPING

Inventors: Andrew Gregory Restivo; Norman Smith

RELATION TO PRIOR APPLCATIONS

[0001] This application claims priority from and through United States Application

62/374,281 titled "Modular Subsea Installation and Workover Control System" and filed on August 12, 2016.

BACKGROUND OF THE INVENTION

[0002] Pipes and other flowlines, especially subsea, often require a hot tap. Hot tapping is a method of making a connection to a pipeline while the pipe remains pressurized in such a way as to prevent interruption to the normal flow or operation of the pipeline, and has been carried out extensively subsea for a long time.

[0003] Hot tapping has traditionally been carried out manually by divers, although some automatic systems have been used in the past. However, diver based systems are not possible at deeper water depths outside the range of divers. Further, current diver and land-based hot tap methods can contain metal sealing but this metal sealing is not at the tap, taking place instead at a flange of a clamp or at a tee. Moreover, most current hot tape seals are annular and operate as an annulus isolation seal whose compression is energized by a wellhead compression preload.

FIGURES

[0004] The figures supplied herein illustrate various embodiments of the invention.

[0005] Fig. 1 is a view in partial perspective of an exemplary embodiment of a hot tap clamping system;

[0006] Fig. 2 is a view in partial perspective of a clamp of the exemplary embodiment of a hot tap clamping system of Fig. 1; [0007] Fig. 3 is a cutaway view in partial perspective of the exemplary embodiment of a hot tap clamping system of Fig. 1;

[0008] Fig. 4 is a view of a portion of a valve and a seal of the exemplary embodiment of a hot tap clamping system of Fig. 1;

[0009] Fig. 5 is a view in partial perspective of a hot tap interface of the exemplary embodiment of a hot tap clamping system of Fig. 1;

[0010] Fig. 6 is a view in partial perspective of a portion of the exemplary embodiment of a hot tap clamping system of Fig. 1;

[0011] Fig. 7 is a view in partial perspective of a common interface of the exemplary embodiment of a hot tap clamping system of Fig. 1;

[0012] Fig. 8 is top down cutaway view of a sealer of a further exemplary embodiment of a hot tap clamping system;

[0013] Fig. 9 is top down cutaway view of a hot tap drill/plug running tool of the further exemplary embodiment of the hot tap clamping system of Fig. 8;

[0014] Fig. 10 is cutaway side view of a metal seal plug of the further exemplary embodiment of the hot tap clamping system of Fig. 8; and

[0015] Figs. 11-17 are cutaway, top down views of the further exemplary embodiment of a hot tap clamping system of Fig. 8 in operation.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0016] Generally, all embodiments of the hot tap clamping systems described herein are operable by a remotely operated vehicle (ROV).

[0017] Referring now generally to Fig. 1, in a first embodiment hot tap clamping system

1000 comprises clamp 10, hot tap assembly 20, hot tap interface 30 operatively connected to and in fluid communication with valve 21, and support 100 operatively connected to actuator interface 40. Support 100 is generally ROV compatible.

[0018] Referring additionally to Fig. 2, in embodiments clamp 10 comprises housing 16 sized to fit over pipe 1, where housing 16 comprises one or more ports 15a, 15b sized to allow insertion of a hot tap therethrough and movable gripper 11 displaced at least partially within housing 16. In certain embodiments, movable gripper 11 comprises movable gripper arms 11a, l ib which are movable between a first position which allows positioning of housing 16 about a predetermined portion of pipe 1 and a second position which secures clamp 10 against pipe 1. Typically, at least one portion of movable gripper 11, e.g. an end portion one or both movable gripper arms 1 la, 1 lb, comprises gripper latch 11c.

[0019] Referring back to Fig. 1, in certain embodiments one or more actuator interfaces

40 are typically present and operatively connected to movable gripper 11 such as via actuator 13 which is also operatively in communication with one or both movable gripper arms 1 la,l lb.

[0020] Referring additionally to Fig. 3, in embodiments hot tap assembly 20 comprises valve 21 operatively connected to clamp 10 at or proximate ports 15a, 15b (Fig. 2); upper portion 23 connected to a portion of valve 21 distally from clamp 10; lower portion 25 connected to a portion of valve 21 proximate clamp 10 and extendable or otherwise sized to engage pipe 1, where lower portion 25 comprises seal 25a (Fig. 4); and valve interface 22 operatively connected to valve 21. Seal 25a is typically a soft metal gasket which can seal to a machine metal seal.

[0021] Referring additionally to Fig. 5, in embodiments hot tap interface 30 comprises one or more aligners 31 and one or more latch receivers 32. Aligners 31 may be configured such that they act as rough/fine aligners, e.g. having an initial opening which narrows as it progresses towards an opposite end of hot tap interface 30. [0022] Referring back to Fig. 1, support 100 typically comprises actuator 101 operatively in communication with actuator 13. As noted above, support 100 is typically ROV compatible.

[0023] Referring now to Fig. 6, in certain embodiments common interface 200 is present and adapted to interface with hot tap interface 30 and provide a connection for different operations such as to machining or coiled tubing 300. Referring additionally to Fig. 7, common interface 200 typically comprises support interface 201 adapted to accept support 100; operations interface 204; and hot tap interface interconnect 203. Hot tap interface interconnect 203 comprises one or more latches 206 configured to be cooperatively received into a corresponding latch receiver 32 and one or more insertion guides 205 configured to be cooperatively received into a corresponding aligner 31.

[0024] In a further embodiment, referring now to Figs. 8 through 10, system for sealing a flowline with a metal seal after hot tapping 1 (Fig. 11) comprises sealer 401, hot tap drill/plug running tool 402 (Fig. 9), and metal seal plug 430 (Fig. 10) which is typically configured for use in sealing a flowline, e.g. pipe 1 (Fig. 1), with a metal seal after hot tapping.

[0025] Referring now to Fig. 8, sealer 401 typically comprises sealer body 415, defining inner annulus 416; clamp 411 disposed about first end 415a of sealer body 415; and valve 412 at least partially disposed within inner bore 417 (not explicitly shown in the figures) where valve 412 comprises inner annulus 412a selectively alignable with inner annulus 416 of sealer body 415 and is adapted to selectively permit or deny fluid continuity between inner annulus 412a of valve 412 and inner annulus 416 of sealer body 415.

[0026] Clamp 411 is adapted to provide structural support for metal seal plug 430 (Fig.

10) and comprises first arcuate arm 411a and second arcuate arm 411b. Second arcuate arm 41 lb is connected to or otherwise part of sealer body 415 and hingedly or pivotally connected to first arcuate arm 41 1a. Second arcuate arm 41 1b comprises inner annulus 41 1c in fluid communication with inner annulus 416 of sealer body 415. Inner annulus 41 lc of second arcuate arm 41 1b typically comprises one or more internal threads 413 configured to cooperatively interface with threaded portion 43 la (Fig. 10) of rotating collar 431 (Fig. 10).

[0027] In these embodiments, sealer connector interface 414 is disposed distally from clamp 41 1 at second end 415b of sealer body 415 and comprises inner annulus 414a in fluid communication with inner annulus 416 of sealer body 415.

[0028] Referring additionally to Fig. 9, hot tap drill/plug running tool 402 comprises connector 421, which comprises inner annulus 421a. Connector 421 is adapted to cooperatively mate with sealer connector interface 414. Hot tap drill/plug running tool 402 further comprises retractable drill shaft 420, comprising first portion 420a extendable through inner annulus 421a of connector 421 ; feed mechanism 425 operatively connected to retractable drill shaft 420, where feed mechanism 425 may comprise a hydraulic or electric motor operatively connected to a lead screw; one or more seals 422 disposed within connector 421 about retractable drill shaft 420, e.g. proximate inner annulus 421a; and one or more guide rods 423 operatively connected to connector 421.

[0029] Referring to Fig. 10, metal seal plug 430 typically comprises rotating collar 431 and substantially tubular portion 433, which is rotatingly disposed within rotating collar 431 and comprises substantially conical sealing surface 432 disposed at a first end portion of substantially tubular portion 433 of metal seal plug 430. Rotating collar 43 1 is adapted to preload metal seal 430 and comprises outer threaded portion 431a configured to transfer torque provided by a running tool into vertical force to preload metal seal 430. Substantially tubular portion 433 is typically a solid tapered completion plug comprising the same or similar material to that of pipe 1 or a corrosion resistant material, which is adapted to seal against a wall of pipe 1 as opposed to sealing on a neck of a tee in a hot tap fitting.

[0030] In the various embodiments, valve 21 (Fig. 1) and/or valve 412 (Fig. 8) typically comprise a ball valve but can comprise a gate valve, a flapper valve, or the like. Moreover, although two clamp arms are illustrated, other configurations may be equivalent, e.g. three clamp arms.

[0031] In the operation of exemplary embodiments, and referring generating to Figs.

11-17, a flowline, e.g. pipe 1 (Fig. 1) may be sealed with a metal seal after hot tapping using the embodiments described above by landing system 1 to a flowline, e.g. pipe 1; disposing clamp 10 (Fig. 1) or clamp 411 (Fig. 8) about a portion of the flowline, e.g. pipe 1; and clamping the system to the flowline using clamp 10 (Fig. 1) or clamp 411 (Fig. 8). In embodiments, after clamping a first pressure test may be performed, typically by using a pressure test port on hot tap drill/plug running tool 402 where the pressure test port can be used by a remotely operated vehicle (ROV) to perform a pressure test and insure system integrity.

[0032] If the first pressure test is performed and successful, or if no first pressure test is performed, a drill bit such as drill bit 424 (Fig. 9) may be connected to retractable drill shaft 420 (Fig. 9) and hot tap drill/plug running tool connector 421 (Fig. 9) connected and mated to sealer body connector interface 414 (Fig. 8) such as by using remote operated connector, e.g. a Grayloc™ ROV clamp as manufactured by Oceaneering International, Inc. of Houston, Texas or other similar connector. If present, guide rods 423 are operatively connected to connector 421 and interface with a motor mounting plate to allow for axial motion. Guide rods 423 may also resist the torque from the motor, e.g. feed mechanism 425. [0033] Valve inner annulus 412a (Fig. 8) is aligned with inner annulus 416 (Fig. 8) of sealer body 415 (Fig. 8) to allow retractable drill shaft 420 (Fig. 9) to advance through inner annulus 416 of sealer body 415 until drill bit 424 engages the flowline and a profile hole drilled. Advancing retractable drill shaft 420 into sealer body annulus 416 until drill bit 424 engages the flowline may comprise advancing drill bit 424 until it reaches a position proximate internal thread 413.

[0034] When the profile hole has been successfully drilled, retractable drill shaft 420 may be retracted into hot tap drill/plug running tool 402.

[0035] Inner annulus 412a (Fig. 8) of valve 412 (Fig. 8) is aligned with inner annulus

416 (Fig. 8) of sealer body 415 (Fig. 8) to remove fluid continuity between a portion of inner annulus 416 of sealer body 415 on one side of valve 412 and a second portion of inner annulus 416 of sealer body 415 on an opposite side of valve 415. Once aligned, hot tap drill/plug running tool 402 is disconnected from sealer body 415. Drill bit 424 (Fig. 9) may then be disconnected from retractable drill shaft 420 (Fig. 9) after which metal seal plug 430 (Fig. 10) may be connected to retractable drill shaft 420 at the end where drill bit 424 was attached. Typically, at this point a second pressure test is performed, by way of example by using the pressure test port on hot tap drill/plug running tool 402 where the pressure test port can be used by a remotely operated vehicle (ROV) to perform a pressure test and insure system integrity.

[0036] If the second pressure test is performed and is successful, or if no second pressure test is performed, hot tap drill/plug running tool 402 may be reconnected and mated to sealer body connector interface 414 (Fig. 8) and inner annulus 412a of valve 412 aligned with inner annulus 416 of sealer body 415 to allow retractable drill shaft 420 to advance through inner annulus 412a of valve 412. Once aligned, retractable drill shaft 420 is advanced into annulus 416 of sealer body 415 and through inner annulus 412a of valve 412 until rotating collar 431 (Fig. 10) engages inner annulus internal thread 413 (Fig. 8) of second arcuate arm 411b (Fig. 8). Threaded portion 431a of rotating collar 431 is then secured into internal thread 413 (Fig. 8) of second arcuate arm 411b after which metal seal plug 430 may be fixedly or removably secured into threaded portion 413. Typically, threaded portion 43 la of rotating collar 431 transfers torque provided by hot tap drill/plug running tool 402 into vertical force to preload metal seal plug 430.

[0037] Once threaded portion 431a of rotating collar 431 is secured into internal thread

413 of second arcuate arm 411b, retractable drill shaft 410 is retracted into hot tap drill/plug running tool 402.

[0038] At this point, a third pressure test may be performed as described above for the first and second pressure tests and, if the third pressure test completes successfully, or if the third pressure test is not performed, valve 412 (Fig. 8) opened and hot tap drill/plug running tool 402 (Fig. 9) disengaged from sealer body 415 (Fig. 8).

[0039] As discussed above, each of the pressure tests, if performed, may be performed using a pressure test port on the drilling tool which may be accessed by an ROV's pumping and pressure test equipment.

[0040] In certain embodiments, clamp 10 (Fig. 1) or clamp 411 (Fig. 8) seals and valve

412 are only used for pressure containment during tapping operations. In certain embodiments as well, once metal seal plug 430 is set, valve 412 and seals only serve as backup to metal seal plug 430.

[0041] As can be understood by one of ordinary skill in these arts, the tapered metal seal plug 430 seals against a wall of pipe 1 rather sealing on a neck of a tee in a hot tap fitting as is taught by the prior art. In addition, one of ordinary skill in these arts will appreciate that clamp 10 or clamp 411, depending on the embodiment, serves as a structural support for metal seal plug 430. In most of the embodiments, the sealer body, e.g. sealer body 415, and the clamp, e.g. clamp 10 or clamp 411, remain attached to pipe 1 after the hot tap operation is completed.

[0042] The foregoing disclosure and description of the inventions are illustrative and explanatory. Various changes in the size, shape, and materials, as well as in the details of the illustrative construction and/or an illustrative method may be made without departing from the spirit of the invention.