Abb Vetco Gray Incorporated

Robert O Lilley

Stephen Paul Fenton

David Stewart Christie

Walter J Lacey

Peter A Scott

A subsea wellhead assembly has a tubular housing having a sidewall, an axial bore, and a housing lateral passage extending from the bore through the sidewall. A blocking sleeve fits around the housing to block the housing lateral passage while drilling through the housing. A tubing hanger is secured to a string of tubing and landed in the housing. The tubing hanger has a vertical passage which communicates with the tubing and a tubing lateral passage which extends from the vertical passage and registers with the housing lateral passage. A lower annulus port is in the sidewall of the housing below the lower seal and leads to a tubing annulus. An upper annulus port is in the sidewall of the housing above the upper seal and leads to the bore of the housing. A tree block having a central opening for receiving the housing is lowered over the housing after removal of the blocking sleeve. The tree block has a tree production passage which registers with the housing lateral passage for directing flow of production fluid from the well. A production valve is mounted to the tree block for opening and closing the tree production passage. A bypass passage in the tree block connects the upper and lower annulus ports to communicate the bore above the tubing hanger with the tubing annulus.

Horizontal tree block for subsea wellhead and completion method

A subsea well has a an outer wellhead housing with a tree on an upper end and a tubing hanger landed in the bore of the tree. A tree cap lands on and is secured to the tree. The tree cap has a plurality of production and annulus valves and a dual-bore control pod assembly. The tree has annulus bypass passages which communicate with a tubing annulus on a lower end and upper ports in the tubing hanger on an upper end. Production fluids flow up the tubing hanger bore to the tree cap and circulates through a flowline in the control pod. Access to the tubing annulus is through the annulus passages and tree cap annulus passage to a separate flowline.

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Farno, Italy

Robert O Lilley