Apparatus for carrying out underwater wellhead operations

Claim 2

Apparatus for carrying out underwater operations between a wellhead on the ocean bottom and a vessel floating on the water wherein said vessel is subject to wave motion, said apparatus comprising: interconnection means suspended from said floating vessel and adapted to operatively engage said wellhead to thereby provide fluid communication between said vessel and said wellhead; and hydropneumatically controlled wave motion canceling means adapted to compensate for any wave motion acting on said vessel, said interconnection means extending through said wave motion canceling means and being operatively coupled to said wave motion canceling means; and said wave motion canceling means in addition being releasably carried by said floating vessel and including a downwardly and outwardly flared opening at its lowermost end.

Claim 3

Apparatus for carrying out underwater operations between a wellhead on the ocean bottom and a vessel floating on the water wherein said vessel is subject to wave motion, said apparatus comprising: interconnection means suspended from said floating vessel adapted to operatively engage said wellhead to thereby provide fluid communication between said vessel and said wellhead; and hydropneumatically controlled wave motion canceling means operatively engaging said interconnection means, said wave motion canceling means including a substantially cylindrical body element and plurality of hydraulic cylinders slidably and outwardly engaging said body element, at least some of said cylinders having their piston rods disposed in an upwardly directed position and at least some of said cylinders having their piston rods disposed in a downwardly directed position; the upper and lower ends of all of said cylinders lying substantially in the same plane; and upper and lower plate means abutting the upper and lower ends of all of said cylinders, respectively, for retaining said cylinders therebetween, said plate means having apertures therein for passing all of said piston rods slidably therethrough.

Claim 4

Apparatus for carrying out underwater operations between a wellhead on the ocean bottom and a vessel floating on the water wherein said vessel is subject to wave motion, said apparatus comprising: interconnection means suspended from said floating vessel adapted to operatively engage said wellhead to thereby provide fluid communication between said vessel and said wellhead; and hydropneumatically controlled wave motion canceling means operatively engaging said interconnection means, said wave motion canceling means including a substantially cylindrical body element and plurality of hydraulic cylinders slidably and outwardly engaging said body element, at least some of said cylinders having their piston rods disposed in an upwardly directed position and at least some of said cylinders having their piston rods disposed in a downwardly directed position; the upper and lower ends of all of said cylinders lying substantially in the same plane; and upper and lower plate means abutting the upper and lower ends of all of said cylinders, respectively, for retaining said cylinders therebetween, said plate means having apertures therein for passing all of said piston rods slidably therethrough.

Claim 5

The apparatus of claim 2 including a bushing member fastened to the free ends of the upwardly directed piston rods, said bushing member being slidably mounted on said cylindrical body element; and the free ends of the downwardly directed piston rods being fixedly secured to approximately the lowermost end of said body element.

Claim 6

The apparatus of claim 2 wherein said bushing member includes abutment means thereon adapted to releasably retain slip means connected to said vessel to thereby releasably retain said wave motion cancelling means in fixed position with respect to said vessel.

Claim 7

The apparatus of claim 4 wherein said body element includes bushing member limit means at its upper end adapted to be engaged by said bushing member to limit the upper movement thereof with respect to said body element.

Claim 8

The apparatus of claim 5 wherein said hydropneumatically controlled wave motion cancelling means includes hydraulic fluid supply means coupled to said cylinders for selectively supplying sufficient hydraulic fluid thereto to selectively release and transfer the load to and from said bushing member to said cylinders.

Claim 9

The apparatus of claim 6 wherein said hydropneumatically controlled wave motion cancelling means further includes hydraulic fluid supply control means operatively engaging said hydraulic fluid supply means for maintaining sufficient hydraulic fluid under pressure in said cylinders so that vertical motion on said vessel is not translated into motion on said interconnecting means.

Claim 10

The apparatus of claim 7 wherein said hydraulic fluid supply control means includes a surge cylinder having a compressible pressure gas side and a non-compressible hydraulic fluid side, the pressure gas side being adapted to be adjusted to balance the weight of the interconnection means when the hydropneumatically controlled wave motion cancelling means is positioned at its desired elevation with respect to said vessel.