Offshore drilling system, vessel and method
AssigneeItrec B.V.
InventorDiederick Bernardus Wijning
Life of this patent
Estimating the term…
Abstract
The first aspect of the present invention relates to an offshore drilling system and a method for performing subsea wellbore related activities involving a riser extending between the vessel and a subsea wellbore. The offshore drilling system comprising a drilling vessel with a floating hull, a drilling tower and a tubular string main hoisting device. A vertically mobile working deck with a rig floor slip device is positioned above the moonpool. A telescopic joint and a diverter are provided, wherein the inner barrel of the telescopic joint is secured to the diverter via a flexible joint. Furthermore an integrated heave compensation system is provided such that said travelling block and the mobile working deck move synchronously in heave compensation.
Claims21
An offshore drilling system for performing subsea wellbore related activities involving a riser extending between a vessel and a subsea wellbore, the offshore drilling system comprising a drilling vessel with:
- a floating hull comprising a moonpool;
- a drilling tower positioned on said hull at or near the moonpool;
- a tubular string main hoisting device comprising:
- a main hoisting winch and a main cable driven by said main hoisting winch;
- a crown block;
- a travelling block suspended from said crown block via said main cable, the travelling block being configured to suspend a tubulars string, therefrom along a firing line through said moonpool;
- a vertically mobile working deck positioned above the moonpool and vertically movable with respect to the drilling tower along the firing line within a motion range including a heave compensation motion range;
- a rig floor slip device arranged on said mobile working deck and configured to suspend therefrom the tubulars string along the firing line through said riser to the wellbore;
- a telescopic joint for compensating the length of said riser, the telescopic joint comprising an outer barrel configured to be connected to a fixed length section of the riser, and an inner barrel movable relative to the outer barrel;
- a diverter configured to divert a hydrocarbon and/or drilling mud stream flowing up through the riser;
- wherein the inner barrel of the telescopic joint is secured to the diverter via a flexible joint;
- a riser tensioning system comprising a tension ring connected to the fixed length section of the riser or to the outer barrel of the telescopic joint, and tension members connected to said tension ring and to the floating hull;
- and
- an integrated heave compensation system configured to provide a heave compensation of the travelling block as well as of the mobile working deck, such that, in operation, said travelling block and the mobile working deck move synchronously in heave compensation,
- wherein in an operational modus:
- the diverter is connected stationary to the floating hull;
- and
- a mechanical connector is tensioned between the fixed length section of the riser or to the outer barrel of the telescopic joint on the one end, and the mobile working deck.
An offshore drilling system for performing subsea wellbore related activities involving a riser extending between a vessel and a subsea wellbore, the offshore drilling system comprising:
- a floating hull comprising a moonpool;
- a drilling tower positioned on said hull at or near the moonpool;
- a tubular string main hoisting device comprising:
- a main hoisting winch and a main cable driven by said main hoisting winch;
- a crown block;
- and
- a travelling block suspended from said crown block via said main cable, the travelling block being configured to suspend a tubulars string therefrom along a fitting line extending through said moonpool;
- a vertically mobile working deck positioned above the moonpool and vertically movable with respect to the drilling tower along the firing line within a motion range including a heave compensation motion range;
- a mobile working deck support cylinder, the support cylinder being connected to the vessel and to the mobile working deck to vertically move the working deck relative to the vessel, within the motion range including the heave compensation motion range,
- a heave compensation system configured to provide heave compensation of the travelling block as well as of the mobile working deck, the heave motion compensation system comprising:
- a heave compensation cylinder, the heave compensation cylinder being connected to a gas buffer for providing the main hoisting device with passive heave compensation;
- and
- a sheave head, comprising one or more sheaves engaging the main cable of the main hoisting device, wherein the sheave head is supported by a piston of the heave compensation cylinder for movement along a heave compensation trajectory,
- wherein the mobile working deck support cylinder is hydraulically connected with the heave compensation cylinder of the heave compensation system, such that in operation the mobile working deck support cylinder moves synchronously with the heave compensation cylinder of the heave compensation system, and thus the mobile working deck moves synchronously with the travelling block;
- and
- a mobile working deck dynamic positioning system, for moving the mobile working deck along the firing line within the motion range including the heave compensation motion range, wherein the mobile working deck positioning system comprises:
- a positioning winch with an associated positioning cable;
- a control device, the control device being configured to control the speed of the positioning winch;
- and
- one or more sheaves, the sheaves guiding the positioning cable in a loop along the heave compensation trajectory,
- wherein the positioning cable is connected to the piston of the heave compensation cylinder and/or the sheave head of the heave compensation cylinder, such that the positioning winch can pull the piston of the heave compensation cylinder in opposite directions along the heave compensation trajectory and, and thus position the mobile working deck with the mobile working deck support cylinder that is hydraulically connected to the heave compensation cylinder.
Dependencies are inferred from the claim text.