Method and system for attaching and removing equipment from a wellhead

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurlaity of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the o ther of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said draw down means provided by cable winch means carried by said frame means and cables releasbly attached to said fist guide menas and extending through said second guide means,
• said equipment means includes upper and lower sections releasablly secured together,
• said frame means includes upper and lower frame means,
• said lower frame means supports said lower equipment section,
• said upper equipment section slidably supported on said upper frame means, and
• yieldable urging means connected between said upper frame means and said upper equipment section and yieldably urges said frame means and said lower equipment means upwardly with a force at least equal to the downward force exerted by said frame means.

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said equipment means includes upper and lower sections releasably secured together,
• said frame means includes upper and lower frame means,
• said lower frame means slidably supports said lower equipment section,
• said upper equipment section slidably supported on said upper frame means, and
• yieldable urging means connected between said upper frame means and said upper equipment section and yieldably urges said frame means upwardly with a force at least equal to the downward force exerted by said frame means.

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said draw down means provided by cable winch means carried by said frame means and cables releasably attached to said first guide means and extending through said second guide means,
• said equipment means includes upper and lower sections releasably secured together,
• said frame means includes upper and lower frame means,
• said lower frame means slidably supports said lower equipment section,
• said uppwer equipment section slidably supported on said upper frame means, and
• yieldable urging means connected between said upper frame means and said upper equipment section and yieldably urges said frame means upwardly with a force at least equal to the downward force exerted by said frame means.

A system for installing subsea devices comprising,

• welllhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said equipment means slidably supported on said frame means, and
• yieldable urging means connected between said equipment means and said frame means urging said frame means upwardly with a force at least equal to the downward force exerted by aid frame means.

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said draw down means provided by cable winch means carried by said frame means and cables releasably attached to said first guide means and extending through said second guide means,
• said equipment means slidably supported on said frame means, and
• yieldable urging means connected between said equipment means and said frame means urging said frame means upwardly with a force at least equal to the downward force exerted by said frame means.

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said equipment means suspended from a flexible riser pipe,
• said riser pipe spooled on a reel supported at the surface by a vessel, and
• means on said vessel controls rotation of said reel to pay out and take in said riser pipe and provides motion compensation between said vessel and the suspended riser pipe while said draw down means are in tension.

A system for installing subsea devices comprising,

• wellhead means including a plurality of upwardly extending first guide means,
• equipment means to be landed including frame means having second guide means cooperable with said first guide means to align said frame means with said wellhead means,
• a plurality of draw down means carried by one of said frame means and said wellhead means and having means releasably attached to the other of said frame means and said wellhead means to draw down said frame means and engage said first and second guide means,
• said equipment means suspended from a flexible riser pipe,
• said riser pipe spooled on a reel supported at the surface by a vessel, and
• means on said vessel controls rotation of said reel to pay out and take in said riser pipe and alternatively maintains said suspended riser pipe in tension while said draw down means are in tension and provide motion compensation between said vessel and the suspended riser pipe.

As a subcombination:

• subsea wellhead means carrying a plurality of upwardly extending first guide means;
• equipment means to be landed including frame means having second guide means on the lower end of said frame means cooperable with said first guide means to align said frame means with said first guide means;
• said frame means including upper and lower frame means;
• said equipment means including an upper equipment section slidably supported on said upper equipment frame means,
• said equipment means including a lower equipment section supported on said lower frame means,
• means releasably latching said upper and lower frame means together,
• means releasably latching said upper and lower equipment sections together,
• and double acting motor means connecting said upper equipment section to said upper frame means.

The method of connecting equipment to a wellhead comprising,

• suspending an equipment frame from a flexible riser pipe carried on a reel on a vessel,
• positioning the equipment frame above the wellhead,
• attaching pull down cables between the equipment frame and wellhead,
• reeling in pull cables while paying out riser pipe from the vessel and landing said equipment frame on said wellhead, and
• while reeling in said cables, urging said equipment frame upwardly relative to said riser pipe by a force at least as great as the downward force exerted by said equipment frame in a motion compensator permitting relative movement between the riser pipe and equipment frame.

The method of connecting equipment to a wellhead comprising,

• suspending an equipment frame from a flexible riser pipe carried on a reel on a vessel,
• positioning the equipment frame above the wellhead,
• attaching pull down cables between the equipment frame and wellhead, and
• reeling in the pull down cables while paying out riser pipe from the vessel and landing said equipment frame on said wellhead, and
• during lowering of said frame from the surface to said wellhead controlling rotation of said reel to provide motion compensation between said vessel and said frame.

The method of connecting equipment to a wellhead comprising,

• suspending an equipment frame from a flexible riser pipe carred on a reel on a vessel,
• positioning the equipment frame above the wellhead,
• attaching pull down cables between the equipment frame and wellhead, and
• reeling in the pull down cables while paying out riser pipe from the vessel and landing said equipment frame on said wellhead, and
• during lowering of said frame from the surface to a position adjacent said wellhead controlling rotation of said reel to provide motion compensation between said vessel and said suspended riser pipe until said cables are attached and therafter maintains said cables in tension until said frame is landed on said wellhead.

The method of connecting equipment to a wellhead comprising,

• suspending an equipment frame from a flexible riser pipe carried on a reel on a vessel,
• positioning the equipment frame above the wellhead,
• attaching pull down cables between the equipment frame and wellhead, and
• reeling in the pull down cables while paying out riser pipe from the vessel and landing said equipment frame on said wellhead, and
• controlling rotation of said reel to maintain said cables in tension while reeling in the pull down cable.

The method of emergency disconnecting and reconnecting equipment to a wellhead comprising;

• unlatching said equipment from the wellhead,
• providing buoyancy to said equipment in excess of the downward force exerted by said equipment to lift it from the wellhead,
• attaching pull down cables between said equipment and wellhead,
• reeling in said cables to reposition the equipment on the wellhead,
• and relatching the equipment to the wellhead.

The method of connecting equipment carried by a frame to a wellhead comprising;

• suspending said equipment and frame from a flexible riser pipe carried on a reel on a vessel,
• positioning the frame and equipment above the wellhead,
• attaching pull down cables between the frame and wellhead,
• urging said frame upward relative to said riser pipe by a force at least equal to the downward force exerted by said frame in a motion compensator permitting relative movement between the riser pipe and the frame,
• reeling in the pull down cables while paying out riser pipe from the vessel and landing said frame on said wellhead with said equipment spaced from said wellhead,
• providing slack in said riser pipe,
• moving said equipment downward relative to the frame and into engagement with said wellhead, and
• latching said equipment to said wellhead.

The method of disconnecting equipment and a flexible riser pipe from a subsea wellhead comprising,

• attaching pull down cables between the equipment and wellhead,
• urging said equipment upwardly relative to said riser pipe by a force at least as great as the downward force exerted by said equipment,
• removing slack from said riser pipe,
• reeling in said riser pipe while simultaneously paying out said pull down cables until the equipment is clear of the wellhead,
• detaching the cables between the equipment and wellhead, and
• reeling in the riser pipe to bring the equipment to the surface.