Upper marine riser package

A self-tensioning slip joint for supporting a load beneath a floating vessel and capable of being lowered through a rotating table on said vessel comprising:

• an inner barrel,
• an outer barrel of a size to telescope over said inner barrel,
• means preventing relative rotation between said barrels,
• a plurality of cylinder assemblies surrounding said barrels and actuatable in parallel with the major axes of said barrels,
• said cylinder assemblies each comprising an outer cylinder and a piston rod reciprocal in said cylinder with a piston attached thereto and with said outer cylinder defining a pressure chamber in said cylinder assembly,
• means for communicating fluid pressure from a high pressure source to said chamber as operating fluid for urging said outer barrel toward a position fully telescoped with said inner barrel,
• said piston rod being attached to a supporting means which moves to said floating vessel and said cylinder being attached to said outer barrel to compensate for the load.

In a self-tensioning slip joint for compensating for vertical movement between a floating vessel and a subsea well, both of which are connected to said slip joint, said slip joint having an inner barrel telescoped over an outer barrel, the improvement comprising,

• means for supporting said inner barrel on a floating vessel,
• a plurality of hydraulically actuated cylinder assemblies,
• means for introducing fluid pressure into said cylinder assemblies to cause said inner and outer barrels to move to compensate for said vertical movement,
• means for connecting said cylinder assemblies to said outer barrel and to said inner barrel support means for independent relative motion therebetween,
• sealing means mounted so as to be moveable with said outer barrel in sliding relationship with said inner barrel for fluid tight sealing relationship therebetween, and
• means for retracting said sealing means from between said inner and outer barrels upwardly through said support means.

For use in offshore drilling, an elongated tubular conduit for connecting a floating vessel to a well bore to pass drilling fluid and drilling tools between said vessel and said well bore, comprising,

• an elongated inner tubular member and an elongated outer tubular member,
• means for attaching said outer tubular member to said well bore,
• means for attaching said inner tubular member to said floating vessel,
• said tubular members being axially aligned and in overlapping telescopic relations in all positions of said vessel relative to said well bore within selected design limits,
• cylinder assemblies attached to one of said telescopic members including a piston and rod attached to said inner tubular member, a cylinder surrounding said piston in axial slideable relationship and attached to said outer tubular member, said cylinder being of a sufficient length to permit axial extension and retraction of said tubular members sufficient to accommodate vessel movement relative to said well bore within said design limits,
• means for supplying pressure fluid to said cylinder for applying substantially continuous force during offshore drilling at a substantially constant pre-selected upward axial force,
• the magnitude of said force exceeding the weight of the tubular conduit plus the weight of any load on said tubular conduit.

In combination, a floating vessel with a platform having a first riser tensioning means to compensate for wave action on said vessel with respect to a subsea well,

• said first riser tensioning means having control and actuating means located on and above said platform,
• a riser string suspended below the vessel,
• means connecting said first riser tensioning means and said riser string above and below said platform,
• a second riser tensioning means on said vessel also to compensate for wave motion on said vessel in the same manner as said first riser tensioning means,
• said second riser tensioning means having actuator means located below said platform and connected to said control means and responsive to said control means, said second riser tensioning means comprising telescoping tubular members with said actuator means located outside said tubular members.

In a vessel having a riser handling spider with an opening through which said riser and other equipment is to be lowered, the steps of making up riser assembly and connecting the same to an upper marine riser package comprises the steps of;

• connecting a plurality of risers to make up a riser string,
• connecting a rotation bearing to a self-tensioning riser slip joint having external actuators,
• connecting said rotation bearing to the last riser of said string,
• lowering said rotation bearing and self-tensioning slip joint and its external actuators through said riser handling spider,
• connecting a tilting means and a diverter to said self-tensioning slip joint,
• lowering said tilting means and said diverter through said riser handling spider, and
• supporting said riser string, rotation bearing, self-tensioning slip joint and tilting means through said diverter by said vessel.