Subsea Connection

This field of this invention relates to connectors, more particularly connectors for umbilicals or flowlines, typically engaged or disengaged by remote-operated vehicles.

In operations involving subsea wellheads, connections are frequently made using remote-operated vehicles (ROVs). The ROV can approach a subsea wellhead and connect an umbilical which is a bundle of control lines, typically used for control of the subsea wellhead and subsurface components, such as a subsurface safety valve. Additionally, a flowline can be connected to the subsea wellhead in a similar manner. In the past, the ROV grasped one-half of the connection which generally contained a centrally mounted shaft having a leading thread. The male thread on the shaft had to be aligned by the ROV to a female thread in the receptacle and thereafter rotational movement of the shaft initiated by the ROV would make up the joint. The difficulties that were encountered in the prior design related to potentials for misalignment between the threaded components which could result in cross-threading. Additionally, any contaminants on the receptacle end of the thread could also hamper the threading operation and prevent the complete sealing of the mating halves of the connection.

Accordingly, it is an object of the present invention to improve the prior designs and to facilitate the alignment between the connection parts prior to securing them together. The need to mate up thread components between the ROV and the subsea wellhead is eliminated in the new design. As a further objective of the new design, the initial interengagement between the mating components does not depend on a threaded connection. Upon interlocking the two segments of the connection to each other, further movement by the ROV of one portion of the connection advances the components together.

A connection is disclosed which is particularly applicable to subsea wellheads. A female receptacle end is provided on the wellhead which has connections on it to an umbilical or a flowline. The male end has an orientation lug for rough orientation. Once rough orientation is made, the male end is advanced into the female end and the shaft rotated by a remotely operated vehicle (ROV) for alignment of lugs with a detent. Once the lugs advance past the detent, they are rotated so that a segment of the shaft on the male end of the connection can no longer turn. Further rotational movements by the ROV on another portion of the shaft advances a plate which makes up the connection, either for the umbilical or the flowline.

FIG. 1 illustrates in sectional elevational view the two components being brought together and coarsely aligned with a lug.

FIG. 2 is the view of FIG. 1, showing how the small lugs on the lower shaft have passed into the detent.

FIG. 3 is the view of FIG. 2, showing entrapment of the lugs on the lower shaft prior to relative rotation of the upper shaft.

FIG. 4 shows the result of rotation of the upper shaft which brings the plate downwardly, thus completing the connection for the umbilical or flowline.

The apparatus of the present invention is illustrated in FIG. 1 as the two segments of the connection are initially brought together. The male segment 10 has a cylindrically shaped body 12, with at least one orientation lug 14. Lug 14 is attached to body 12 by fasteners 16, 18, and 20. Body 12 also has a plate 22. Connected to plate 22 is ring 24, which is held down by fasteners 26. Ring 24 has a shoulder 28 which engages shoulder 30 on ring 32. Ring 32 is connected to upper shaft 34 at grooves 36. The upper shaft 34 rotates in tandem with ring 32 due to the manner of connection into grooves 36. A lower shaft 38 has a pair of tabs 40 and 42 extending radially outwardly. The lower shaft 38 itself extends into ring 32 where there exists a gap between the upper end 44 of the lower shaft 38 and the lower end 46 of the upper shaft 34. Ring 32 has an inwardly extending shoulder 48 which retains the lower shaft 38 within the ring 32, yet permits some relative movement therebetween. The shoulder 48 has a thread which engages thread 50 on lower shaft 38. Plate 22 supports line 52 which can be an umbilical or a flowline for a well. Line 52 terminates in a female connector 54. When lug 14 is aligned with a mating groove (not shown) in the female segment 56, the female connector 54 is in general alignment with the male connector 58, but in the position shown in FIG. 1, although no contact is yet made.

In operation of the connection, the male segment 10 is aligned with the female segment 56 such that the lug 14 is in alignment with a groove in the female segment 56. Having made such a preliminary alignment, the upper shaft 34 is manipulated counterclockwise at hex end 60 by an ROV. Once a travel stop is reached, the tabs 40 and 42 are in alignment with openings 62 and 64, respectively, in retainer 66.

As shown by a comparison between FIGS. 1 and 2, when the tabs 40 and 42 are in alignment with openings 62 and 64, they can literally advance until tabs 40 and 42 are in alignment with windows 68 and 70. At this point, the ROV turns the upper shaft 34 clockwise until the tabs 40 and 42 are transverse to openings 62 and 64 and are incapable of turning further because each of the tabs 40 and 42, respectively, have come to the end of windows 68 and 70, or any other rotational travel stop. At this point, the lower shaft 38 can rotate no further in a clockwise direction and at the same time, due to the misalignment between tabs 40 and 42 and openings 62 and 64, the lower shaft 38 cannot move sufficiently longitudinally for a release from the retainer 66. Thus, FIG. 2 shows the advancement of the tabs 40 and 42 beyond openings 62 and 64 prior to the initiation of clockwise rotation. After clockwise rotation, the position of FIG. 3 is reached, where the tabs 40 and 42 are out of alignment with openings 62 and 64. As shown in FIG. 3, since there is still a net inward force on upper shaft 34 which is communicated to lower shaft 38, the tabs 40 and 42 are bottomed in the windows 68 and 70.

In this position, the thread 50 is now stationary because the tabs 40 and 42 can no longer turn. Accordingly, further clockwise rotation of upper shaft 34 through ring 32, which is connected to the thread 50, advances lower shaft 38 toward upper shaft 34. At the same time, the plate 22 is pulled downwardly until it contacts surface 72 of the retainer 66. Thus, with the tabs 40 and 42 restrained against further upward motion when they contact surface 74 of retainer 66, the female connector 54 is drawn down on the male connector 58 in a sealing relationship.

This tightening of the connection as illustrated by comparing FIGS. 3 and 4 occurs because tandem rotation of upper shaft 34 with ring 32 at first, through the interaction of thread 50 with ring 32 which has a thread 76 adjacent the shoulder 48, the tabs 40 and 42 are drawn upwardly, while at the same time the plate 22 is drawn downwardly. Eventually, both the plate 22 and the tabs 40 and 42 reach their limit of longitudinal travel, at which point the female connector 54 is in sealing engagement with the male connector 58. Male connector 58 leads to the well through conduit 78. The joint can be taken apart by reversing the rotation on upper shaft 34 with an ROV. The above-described movements are simply reversed to result in a release between the male segment 10 and the female segment 56.

Those skilled in the art can appreciate that the dangers of cross-threading are eliminated by this design. The initial link-up of the male segment 10 with the female segment 56 is a bayonet-type connection using the tabs 40 and 42 passing through openings 62 and 64, only to be turned for the initial engagement. Once the initial engagement is made without a threaded connection, the ROV supplies the rotational force to the hex head 60 to bring the trapped tabs 40 and 42 and the plate 22 closer together until they are both firmly against the retainer 66. When they achieve that position, the male connector 58 is in a sealing relationship with the female connector 54. While only a single connection (ie., connectors 54 and 58) is illustrated, those skilled in the art will appreciate that a multiplicity of such connections can be made up all at once with a single operation.

Thus, the ROV (not shown) does not need to achieve perfect alignment to complete the connection as with the past designs which involved the thread on both segments. Here, with only a coarse alignment, the two components of the connection 10 and 56 can be initially secured together for a rotational force which cannot result in cross-threading. Additionally, since the gaps for the windows 68 and 70 are fairly large, even if some foreign materials lodge in that area or settle there, the connection can still be made. This is to be distinguished from the old-style joints wherein a thread had to be started properly for the joint to be brought together so that connectors such as 54 and 58 could come together in a sealing relationship.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.