Subsea drilling
AssigneeGeoprober Drilling Limited
InventorAnthony S. Bamford
Life of this patent
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Abstract
A method and apparatus for drilling subsea wells is provided. A subsea shut off device including ball gripping mechanisms is latched to a template at surface. Drilled in casing can be suspended from the device at any position using the gripping mechanism so that the device is run to the sea floor on the casing string. The casing string is drilled into place and converted into a riser. This is all done on a single trip to speed up the operation and reduce the risk. The casing string is captured and sealed within the subsea shut-off device after installing and spacing out a surface BOP. For the event when emergency disconnection is required, dual shear rams in the device cut the casing and seal in the well. The system then allows a conventional subsea reconnection of the riser.
Claims36
A method of drilling a subsea well comprising the steps:
- a) providing a subsea shut off device including a throughbore, a first gripping mechanism for selective attachment along a length of a casing when located in the throughbore and one or more rams for selectively sealing the throughbore in an emergency;
- b) providing the casing upon which the shut off device is attached thereto by the first gripping mechanism;
- c) running the casing with the shut off device from the surface to the sea floor;
- d) disconnecting the casing from the shut off device;
- e) using the casing to drill the well from the sea floor.
A method of drilling a subsea well comprising the steps:
- a) providing a subsea shut off device including a throughbore, a first gripping mechanism for selective attachment along a length of a casing when located in the throughbore and one or more rams for selectively sealing the throughbore in an emergency;
- b) providing the casing equipped with a bottom hole drilling assembly (BHA), and upon which the shut off device is attached thereto by the first gripping mechanism;
- c) running the casing with the shut off device from the surface to the sea floor;
- d) disconnecting the casing from the shut off device;
- and
- e) using the casing BHA to drill the well from the sea floor whereby the well is drilled and established on a single trip.
Dependencies are inferred from the claim text.