US3488031A - Offshore quick release-reconnect coupling - Google Patents

Description

Jan. 6, 1970 H. P..BEZNER ETAL OFFSHORE QUICK RELEASE-RECONNBCT COUPLING Filed March 18, 1968 2 Sheets-Shed 1 INVENTORS. HUBERT P. BEZNER, JEFFERSON C.TAYLOR,JR., CARROLL .WOOLLEY, LMM/ ATTORNEY.

Jan. 6, 1970 H. P. BE ZNER- Em.

OFFSHORE QUICK RELEASE-RECONNECT COUPLING Filed March 18, I968 2 Sheets-Sheet 2 INVEN'IORS, HUBERT P. BE ZNER JEFFERSON C. TAYLOR JR. CARROLL A. WOOLLEY ATTORNEY.

US. Cl. 251148 4 Claims ABSTRACT OF THE DISCLOSURE A quick release-reconnect coupling for use in drill stem testing from a floating vessel. One coupling member, connected to the lower end of a pipe string suspended from the floating vessel, is lowerable and attachable to a stationary coupling member connected to a subsea tubing extending from a subsea wellhead. A sealed connection between the suspended pipe string and the subsea tubing is effected by lowering, stabbing and latching the coupling member connected to the pipe string onto the stationary coupling member. The latched coupling members are released from each other by applying hydraulic pressure to the coupling member connected to the pipe string. The pipe string may then be disconnected from the subsea tubing by raising the suspended pipe string and the coupling member connected to it. The subsea tubing is preferably provided with a hydraulically operated closure valve which is closed any time there is separation of the pipe string and tubing and can be hydraulically operated or opened after the pipe string and tubing are connected together. The coupling members are formed with passageways to provide for passage of fluid therethrough to operate the tubing closure valve.

BACKGROUND OF THE INVENTION The present invention generally concerns drill stem testing from a floating drilling rig or vessel and more particularly, coupling apparatus for quickly releasing and reconnecting subsea equipment to a pipe string which is suspended from the floating vessel.

Drill stem testing from a floating drilling vessel requires that a rapid, safe shutdown technique be available so that a subsea well can be hurriedly secured when it is necessary to move off the well location because of equipment failure or bad weather. In addition to rapid, safe well shutdown and rapid disconnection of the suspended pipe string and subsea equipment, the coupling should be capable of ready reconnection of the suspended pipe string to the subsea equipment for continued testing of the well or termination of the test.

In many drill stem test operations, a fail safe valve is located in the tubing in or slightly below the subsea blowout preventer (BOP) stack. This valve is held open with hydraulic pressure and automatically closes when that pressure is released. Accordingly, the coupling should provide for passage of fluid therethrough for operation of the hydraulically actuated fail safe valve.

The present invention satisfies all of the aforementioned requirements. A stab-connect, hydraulic-release coupling device is used to rapidly release the pipe string suspended from the floating vessel from the subsea equipment at a point above a closure valve located in the subsea tubing (after releasing opening pressure to allow the closure valve to shut) and reconnect that pipe string to the subsea tubing after the emergency which required shutting in the well and removal of the pipe string is over. The closure valve is again opened after reconnecting the pipe string to the subsea tubing. The hydraulic release feature of the United States Patent 3,488,031 Patented Jan. 6, 1970 ICC coupling is important because motion from the floating vessel renders stab-connect, rotation-release devices undesirable. Two hydraulic conduits, one to control operation of the connector release coupling and the other to control operation of the closure valve in the subsea tubing, extend from the coupling and subsea tubing, respectively, to the floating vessel.

SUMMARY OF THE INVENTION In accordance with the teachings of the invention, the apparatus comprises, briefly, a first hollow coupling member attachable to the lower end of a pipe string suspended from a floating vessel and having a sealing surface and latch means provided with a latch dog; a second hollow coupling member adapted to be connected to subsea equipment and having a latch recess to be engaged by said latch dog and an inner sealing surface adapted to engage said sealing surface of said first coupling member. The first coupling member latches automatically with a positive mechanical locking action when stabbed onto the second coupling member. Application of hydraulic fluid pressure to said latch means permits said latch dog to retract from said latch recess and release of hydraulic fluid pressure from said latch means causes said latch dog to lock in said latch recess. A passageway in said first coupling member communicates with a conduit which extends to the floating vessel for supplying hydraulic fluid to said latch means. Also, other passageways are located in both said first and second coupling members to communicate with another conduit which extends to the floating vessel to supply hydraulic fluid pressure to a hydraulically operated closure valve located in subsea equipment positioned below the coupling members. Engageable splines are provided at the ends of the coupling members to prevent rotation of the coupling members relative to each other.

The objects and advantages of the invention will be more apparent from a more detailed description of the invention which follows.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a pipe string suspended from the water surface coupled to stationary subsea apparatus by means of the release-reconnect coupling of the invention;

FIG. 2 is a vertical view of only the stationary subsea apparatus illustrated in FIG. 1;

FIGS. 3A, 3B are vertical, partly sectional views show ing in greater detail the release-reconnect coupling members of the invention as they are being connected together; and

FIG. 4 is a vertical view of a portion of the coupling members shown in FIG. 3A showing the release-reconnect coupling members when they are completely connected together.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown stationary subsea apparatus generally designated 10 which includes a wellhead 11 arranged on the sea floor 12, a BOP stack 13 mounted 0n the wellhead and a riser latch assembly 14 mounted on the BOP stack 13. A tubing 15 is shown suspended in wellhead 11. Riser latch assembly 14 engages and secures the lower end of a riser or conductor pipe 16 which extends to a floating rig or vessel, not shown.

A ball valve assembly 17 such as one shown on p. 3840 of the 1966-67 Composite Catalog of Oil Field Equipment is connected into a lower tubing or pipe 18. The BOP stack 13 is provided with rams 19 for closing off the annulus surrounding assembly 17. Details of the ball valve assembly are not shown; however, a flexible conduit 20, 20' extends to the earths surface and supplies hydraulic fluid pressure to the ball valve assembly to maintain tubing 18 open. Release of the hydraulic fluid pressure in conduit 20, 20' causes the ball valve assembly to close off tubing 18. The upper end of tubing 18 is screw-threadedly connected to a tubular coupling member 21 which is provided with a latch recess 22 at its upper end (see also FIGS. 3A, 3B and 4). Stationary mandrel coupling member 21 is adapted to be latched to a tubular coupling member 25, the external surface of which is provided with spacer ribs 26 for maintaining coupling member 25 centrally positioned within riser 16. Coupling member 25 is screw-threadedly connected at its upper end to the lower end of a pipe string 28 (see FIG. 3A) which extends to and is suspended from the floating vessel. A flexible conduit 29 is connected at its lower end to the upper end of coupling member 25. This conduit also extends upwardly along pipe string 28 to a source of hydraulic fluid pressure on the floating vessel.

Referring to FIGS. 3A, 3B and 4 for a more detailed description of the connection between coupling members 21 and 25, there is shown on the interior surface of coupling member 21 below latch recess 22 a splined portion 40 and a passageway 41. The upper end of passageway 41 terminates at a port 42 and the lower end thereof terminates at a port connected to conduit 20 (see FIG. 1). The interior surface 43 of coupling member 21 forms a seal with a complementary surface 43' of coupling member 25.

Coupling member 25 includes a stinger member 44 having a splined portion 45 on its lower exterior surface which is adapted to engage and mesh with the splined portion 40 of coupling member 21. Coupling member 25 also contains a passageway 46, the lower end of which terminates in a port 47 which aligns with port 42 in coupling member 21 when the coupling members are latched together, as illustrated in FIG. 4. Outer sealing surface 43' surrounding port 47 sealingly engages surface 43 when the coupling members are latched together. Another passageway 48 formed in coupling member 25 is attached to conduit 29 at its upper end and terminates at its lower end in a chamber 49 formed in coupling member 25. A piston 50, latch sleeve 51 and a spring 52 are arranged in chamber 49. Latch sleeve 51 is provided with an inner upper recess 53 and an inner lower recess 54. A lug sleeve 55 having an outer recess 56 is located in a recessed portion 57 formed in coupling member 25. A spring 58 is also located in recessed portion 57. A lug 60 is arranged in a slot located in coupling member 25. Lug 60 is positioned so as to engage recess 53 in latch sleeve 51 and recess 56 in lug sleeve 55. A latch dog 61 is arranged in another slot located in coupling member 25. Latch dog 61 is positioned so as to engage recess 54 and recess 22 (in coupling member 21).

OPERATION When it is desired to connect pipe string 28 to tubing 18, the lower end of pipe string 28 to which coupling member 25 is attached is lowered along with conduits 20' and 29 through riser 16 until the level of coupling member 21 is reached. As best illustrated in FIGS. 3A, 3B and 4, coupling member 25 is further lowered until stinger 44 slides into the upper end of coupling member 21 and splined portions 40 and 45 engage and mesh together. A coupling member 25 is lowered into coupling member 21, the top of coupling member 21 engages the bottom of lug sleeve 55 and forces lug sleeve 55 upwardly against the bias of spring 58. Such action positions latch recess 22 adjacent latch dog 61 and permits lug 60 to move inwardly out of recess 53 of latch sleeve 51. In that manner, latch sleeve 51 is permittedto move upwardly under the bias of spring 52 to urge and then retainlatch dog 61 engaged with latch recess 22. Coupling members 21 and 25 are now releasably latched together. Sealing surfaces 43 and 43' effetltively seal ofi the interior and exterior of the coupling members and effectively isolate the flow path through passageways 41 and 46. In this position of the coupling members, hydraulic fluid pressure is applied from the floating vessel through conduit 20, passageway 46, port 42, conduit 41 and conduit 20 to the ball valve or closure assembly 17 to actuate the valve and thereby maintain tubing 18 open.

When it is desired to release pipe string 28 from tubing 18, hydraulic pressure is released from the ball valve assembly 17 to permit the valve assembly to close tubing 18 automatically. Then, hydraulic pressure is applied from the floating vessel through conduit 29 to chamber 49 above piston 50 to force latch sleeve 51 downwardly against the bias of spring 52 to permit latch dog 61 to retract from engagement with latch recess 22 on coupling member 21. Coupling member 25, together with pipe string 28, is then raised and removed from riser 16. Lug sleeve 55 moves down under the bias of spring 58 and urges lug 60 outwardly into recess 53 in latch sleeve 51. Lug 60 retains latch sleeve 51 in the down or cocked position.

What is claimed is:

1. Apparatus for use in offshore operations comprising:

a first hollow coupling member adapted to be attached to the lower end of a pipe string suspended from a floating vessel;

a second hollow coupling member adapted to be connected to subsea equipment and to said first coupling member and having a latch recess located adjacent the upper end thereof and an inner sealing surface;

said first coupling member having mechanical locking and hydraulically releasable latch means provided with a latch dog adapted to engage and be locked in said latch recess when said first and second coupling members are connected together;

said first coupling member having an outer sealing surface adapted to engage sealingly said sealing surface of said second coupling member when said first and second coupling members are connected together;

a first passageway in said first coupling member and a second passageway in said second coupling member, said first and second passageways forming a sealed off, continuous flow path through said coupling members when said coupling members are connected tog'ether; and

means adapated to supply hydraulic fluid pressure to said latch means to permit said mechanically locked latch dog to retract and disengage from said latch recess.

2. Apparatus as recited in claim 1 including means arranged on the lower end of said first coupling member and on the upper end of said second coupling member adapted, when said coupling members are connected together, to prevent rotation of said coupling members relative to each other.

3. Apparatus as recited in claim 2 including a hydraulically operatable closure valve arranged in said subsea equipmentfsaid first passageway in said first coupling member being adapted to be connected to a source of hydraulic fluid pressure and said second passageway in said second coupling member being adapted to be connected to said hyraulically operated closure valve.

4. Apparatus as recited in claim 3 wherein said latch means includes:

a chamber;

a piston arranged in said chamber adapted to be moved in one longitudinal direction upon application of hy draulic fluid pressure to said chamber when said coupling members are connected together;

a first sleeve member provided with two spaced apart recesses arranged in said chamber below said piston;

a first spring arranged in said chamber below said 5 6 first sleeve member adapted to bias said first sleeve lug member to move into said one recess in said member in an opposite longitudinal direction; first sleeve member and to permit said latch dog a second sleeve memberprovided with arecess; to move into said other recess in said first sleeve a second spring adapted to bias said second sleeve member to permit disconnection of said first and member in said one longitudinal direction; 5 second coupling members. a lug member adapted to engage said recesses in said References Cited first and second sleeve members; said latch dog adapted to engage one of said recesses UNITED STATES PATENTS in said first sleeve member whereby when said cou- 2 949 9 3 19 0 McGowen et 1 251 143 p g members are engaged and Said latch dog is 10 3,325,190 6/1967 Eckert et a1. 285-18 latched in said latch recess, said second sleeve mem- 3 333 370 7 19 7 Watkins 285 1g ber is moved in said opposite longitudinal direction 3 3 5 7 7 Knox 5*1 against the bias of said second spring to permit said lug member to move out of one of said recesses in CARY NELSON Pnmary Examiner said first sleeve member and application of hydrau- 15 WILLIAM R. CLINE, Assistant Examiner lic fluid pressure to said chamber moves said piston U S Q X R and said first sleeve member in said one direction 285 18 141 316 against the bias of said first spring to permit said

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