Subsea wellhead completion systems

Claim 2

A subsea wellhead completion assembly for mounting on a casing set in a well which comprises: a tubing hanger means anchored with respect to said casing; a tubing string suspended in the well from said tubing hanger means; a wellhead control assembly extending above said tubing hanger and forming a vertical bore therein; a tubing extension member extending upwardly from said tubing hanger and in fluid communication with said string of tubing; means sealing the annular space between the upper end of said tubing extension and the inner wall of said bore; lateral outlet means on said wellhead control assembly; valve means in said tubing extension for establishing fluid communication between the interior thereof and said outlet means; closure means for the top of said wellhead assembly, said closure means includes: a utility stub placed on the top of said wellhead assembly; a cap means sealingly fitted within said utility stub, said cap having an internal bore with internal latching grooves therein; latching means for releasably latching said cap to said utility stub; the top of said tubing extension being provided with means for connecting into a tubing string.

Claim 3

An apparatus as defined in claim 1 in which said tubing extension includes a removable valve in the upper end thereof.

Claim 4

An apparatus as defined in claim 1 including a removable wire-line operable valve in the upper end of said tubing extension member.

Claim 5

A subsea wellhead completion apparatus in which casing has been set in the earth beneath a body of water which comprises: a first blowout preventer means connected to the upper end of said casing; an outlet spool having a lateral outlet and connected to the top of said first blowout preventer; a second blowout preventer means connected to the upper side of said outlet spool; a utility stub connected above said second blowout preventer means, there being formed a vertical bore through said first blowout preventer means, said outlet spool, said second blowout preventer means, and said utility stub; a tubing hanger in said casing and having a string of tubing extending downwardly therefrom; a tubing extension means extending from said tubing hanger upwardly in said bore, said tubing extension having a valve therein which can be opened from the surface, the upper end of said tubing extension having a receptacle for tubing connection, said receptacle being below said second blowout preventer means; sealIng means just below said receptacle of said tubing extension means and sealing the annular space between the tubing extension and the wall of said bore; removable cap means in the upper end of said utility stub; and means on the upper end of said utility stub for aiding in guiding a member into said stub.

Claim 6

A subsea wellhead completion apparatus in which casing has been set in the earth beneath a body of water which comprises: a first blowout preventer means connected to the upper end of said casing; an outlet spool having a lateral outlet and connected to the top of said first blowout preventer; a second blowout preventer means connected to the upper side of said outlet spool; a utility stub connected above said second blowout preventer means, there being formed a vertical bore through said first blowout preventer means, said outlet spool, said second blowout preventer means, and said utility stub; a tubing hanger in said casing and having a string of tubing extending downwardly therefrom; a tubing extension means extending from said tubing hanger upwardly in said bore, said tubing extension having a valve therein which can be opened from the surface, the upper end of said tubing extension having a receptacle for tubing connection, said receptacle being below said second blowout preventer means; sealIng means just below said receptacle of said tubing extension means and sealing the annular space between the tubing extension and the wall of said bore; removable cap means in the upper end of said utility stub; and means on the upper end of said utility stub for aiding in guiding a member into said stub.

Claim 7

A subsea wellhead completion assembly for mounting on casing set in a well which comprises: a vertical housing means having a vertical bore therethrough and aligned with said casing; upper remotely operated valve means for closing the said vertical bore; a tubing hanger means anchored with respect to said casing; a tubing string suspended in the well from said tubing hanger means; a tubing extension mandrel means extending upwardly from said tubing hanger into said vertical bore, said mandrel means including means sealing the mandrel means with the wall of said bore below said upper closure means; lateral outlet means on said housing means and including means establishing fluid communication with the interior of said tubular extension mandrel means; removable means closing the upper end of said tubing extension mandrel means; cap means closing the upper end of said vertical bore above said upper remotely operated valve means.

Claim 8

A subsea wellhead completion assembly for mounting on casing set in a well which comprises: a vertical housing means having a vertical bore therethrough and aligned with said casing; upper remotely operated valve means for closing the said vertical bore; a tubing hanger means anchored with respect to said casing; a tubing string suspended in the well from said tubing hanger means; a tubing extension mandrel means extending upwardly from said tubing hanger into said vertical bore, said mandrel means including means sealing the mandrel means with the wall of said bore below said upper closure means; lateral outlet means on said housing means and including means establishing fluid communication with the interior of said tubular extension mandrel means; removable means closing the upper end of said tubing extension mandrel means; cap means closing the upper end of said vertical bore above said upper remotely operated valve means.

Claim 9

An assembly as defined in claim 5 in which said tubing extension mandrel has two vertical bores therethrough said lateral outlet means includes two outlets communicating independently with said vertical conduits of said tubing extension mandrel, said outlets being curved to accommodate through-the-flowline tools.

Claim 10

A subsea wellhead assembly as defined in claim 5 including a riser pipe in sealed fluid communication with the bore of said housing, said riser pipe extending to a nonwater environment so that well operations can be conducted through said riser pipe.

Claim 13

A method as defined in claim 8 including the step of killing the said well by pumping a killing fluid from said nonwater environment through said tubing to said well.

Claim 14

A subsea wellhead completion assembly for mounting on casing set in a well which comprises: a vertical housing means having a vertical bore therethrough and aligned with said casing; upper closure means for closing the said vertical bore; a tubing hanger means anchored with respect to said casing; a tubing string suspended in the well from said tubing hanger means; a tubing extension mandrel means extending upwardly from said tubing hanger into said vertical bore, said mandrel means including means sealing the mandrel means with the wall of said bore below said upper closure means; lateral outlet means on said housing means and including means establishing fluid communication with the interior of said tubular extension mandrel means; removable means closing the upper end of said tubing extension mandrel means; a first blowout preventer positioned just above the tubing hanger and a second blowout preventer means positioned above said tubing extension mandrel.

Claim 15

A subsea wellhead completion assembly for mounting on casing set in a well which comprises: a vertical housing means having a vertical bore therethrough and aligned with said casing; upper closure means for closing the said vertical bore; a tubing hanger means anchored with respect to said casing; a tubing string suspended in the well from said tubing hanger means; a tubing extension mandrel means extending upwardly from said tubing hanger into said vertical bore, said mandrel means including means sealing the mandrel means with the wall of said bore below said upper closure means; lateral outlet means on said housing means and including means establishing fluid communication with the interior of said tubular extension mandrel means; removable means closing the upper end of said tubing extension mandrel means; a first blowout preventer positioned just above the tubing hanger and a second blowout preventer means positioned above said tubing extension mandrel.

Claim 16

An assembly as defined in claim 10 in which said housing means includes at its upper end a utility stub; a cap means having an internal bore with an internal groove therein releasably latched to the upper end of said utility stub; said assembly further including; fluid control conduits in the wall of said stub which include extensions frOm such conduits to said first and second blowout control means; a riser pipe extending from said utility stub to a nonwater environment, the wall of said riser pipe having control conduits for mating with the control conduits of said utility stub; orienting means on said riser pipe and said utility stub for securing proper alignment between the control fluid conduits of said riser pipe and those of said utility stub.