A process for installing the payload onto a subsea structure has the steps of affixing an adapter spool on to the subsea structure, deploying a plurality of winches in spaced relation to the subsea structure, connecting an end of a plurality of slings received on the plurality of sheaves to a plurality of winches, connecting an opposite end of the plurality of slings to the payload, lowering the payload in a direction toward the subsea structure, actuating the plurality of winches so as to draw the payload downwardly into a position on the subsea structure, and locking the payload onto the subsea structure. The adapter spool has a collar with a plurality of sheaves extending outwardly therefrom. The payload can be a capping stack and the subsea structure can be a blowout preventer.

A process for installing the payload onto a subsea structure has the steps of affixing an adapter spool on to the subsea structure, deploying a plurality of winches in spaced relation to the subsea structure, connecting an end of a plurality of slings received on the plurality of sheaves to a plurality of winches, connecting an opposite end of the plurality of slings to the payload, lowering the payload in a direction toward the subsea structure, actuating the plurality of winches so as to draw the payload downwardly into a position on the subsea structure, and locking the payload onto the subsea structure. The adapter spool has a collar with a plurality of sheaves extending outwardly therefrom. The payload can be a capping stack and the subsea structure can be a blowout preventer.

A cap for a hydrocarbon production well, the cap having a body with a top and a bottom. The bottom having a first connecting flange with a first seal face. The first connecting flange configured to connect to an end flange of a wellhead component and the top having a second connecting flange with a second seal face.

A cap for a hydrocarbon production well, the cap having a body with a top and a bottom. The bottom having a first connecting flange with a first seal face. The first connecting flange configured to connect to an end flange of a wellhead component and the top having a second connecting flange with a second seal face.

The invention concerns a method for installing a hatch (34) to a subsea structure (10) by connecting the hatch to the subsea structure by at least one hinge (20) having a first mounting portion (21), a second mounting portion (22), a flexible portion (23) interconnecting the first and second mounting portion allowing a pivot connection between the first and second mounting portion. The installation steps comprise •—inserting a protrusion (23) of the first mounting portion (21) into an installation hole arranged in the subsea structure (10), •—inserting a protrusion (24) of the second mounting portion (22) into an installation hole arranged in the hatch (34), thereby •—engaging the first mounting portion (21) of the hinge (20) for anchorage with the subsea structure (10) and engaging the second mounting portion (22) for anchorage with the hatch (34) thereby arranging for the hatch to pivot between a closed and an open position about a pivot axis provided by the flexible portion of the hinge. The invention also concerns a hinge and an assembly for subsea use.

The invention concerns a method for installing a hatch (34) to a subsea structure (10) by connecting the hatch to the subsea structure by at least one hinge (20) having a first mounting portion (21), a second mounting portion (22), a flexible portion (23) interconnecting the first and second mounting portion allowing a pivot connection between the first and second mounting portion. The installation steps comprise •—inserting a protrusion (23) of the first mounting portion (21) into an installation hole arranged in the subsea structure (10), •—inserting a protrusion (24) of the second mounting portion (22) into an installation hole arranged in the hatch (34), thereby •—engaging the first mounting portion (21) of the hinge (20) for anchorage with the subsea structure (10) and engaging the second mounting portion (22) for anchorage with the hatch (34) thereby arranging for the hatch to pivot between a closed and an open position about a pivot axis provided by the flexible portion of the hinge. The invention also concerns a hinge and an assembly for subsea use.

Method of stopping production and making safe an undersea bottom-to-surface connection production pipe having a first pipe portion on the sea bottom from a well head to the bottom end of a second pipe portion extending to a ship or floating support. After stopping production, depressurization of the entire undersea bottom-to-surface connection production pipe is performed. Thereafter, the following steps are preformed: isolating the first production pipe portion from the second pipe portion, and leaving the production fluid in the first production pipe portion, but not in said second pipe portion, depressurizing the first production pipe portion filled with production fluid by reducing the pressure in the first pipe portion and by discharging more completely the gas contained in the production fluid that it contains.

Method of stopping production and making safe an undersea bottom-to-surface connection production pipe having a first pipe portion on the sea bottom from a well head to the bottom end of a second pipe portion extending to a ship or floating support. After stopping production, depressurization of the entire undersea bottom-to-surface connection production pipe is performed. Thereafter, the following steps are preformed: isolating the first production pipe portion from the second pipe portion, and leaving the production fluid in the first production pipe portion, but not in said second pipe portion, depressurizing the first production pipe portion filled with production fluid by reducing the pressure in the first pipe portion and by discharging more completely the gas contained in the production fluid that it contains.

Transducer assembly for an offshore drilling riser, in an example, includes a spool for connecting into the riser and a protrusion extending around the side wall of the spool. A recess extends around the protrusion between upper and lower sloping surfaces. Upper transducer bores are spaced around the protrusion and extend from the upper sloping surface downward and inward into the spool bore and lower transducer bores extend from the lower sloping surface upward and inward into the spool bore. A base of a rigid non-metallic material is located in each of the transducer bores. A seal ring extends around a cylindrical exterior portion of each of the bases and one of the transducer bores. An acoustic transducer element is mounted to the outer end of each of the bases. The transducer assembly can detect drilling fluid and form sealing.

Transducer assembly for an offshore drilling riser, in an example, includes a spool for connecting into the riser and a protrusion extending around the side wall of the spool. A recess extends around the protrusion between upper and lower sloping surfaces. Upper transducer bores are spaced around the protrusion and extend from the upper sloping surface downward and inward into the spool bore and lower transducer bores extend from the lower sloping surface upward and inward into the spool bore. A base of a rigid non-metallic material is located in each of the transducer bores. A seal ring extends around a cylindrical exterior portion of each of the bases and one of the transducer bores. An acoustic transducer element is mounted to the outer end of each of the bases. The transducer assembly can detect drilling fluid and form sealing.