Offshore floating vessel and a method of operating the same

Patent metadata

Field	Value
Publication number	US-9630813-B2
Application number	US-201414785026-A
Country	US
Kind code	B2
Filing date	Apr 22, 2014
Priority date	Apr 18, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

An offshore floating vessel includes a hoisting system including a drive for moving connecting device and emergency brakes to inhibit motion of the connecting device; wherein the hoisting system is to be operated at least in a hoisting mode and in an active heave compensation mode; wherein hoisting system is to perform an active heave compensation when operated in the active heave compensation mode and to operate without active heave compensation when operated in the hoisting mode; wherein the emergency brakes are operable in a normally-energized mode including a de-energized state where the emergency brakes engage so as to inhibit motion of the connecting device relative to the floating vessel; wherein the hoisting system is operable in a fixed-to-bottom mode; wherein the hoisting system is to perform an active heave compensation when operated in fixed-to-bottom mode; and wherein the hoisting system is adapted to prevent the emergency brakes from engaging.

First claim

The invention claimed is:

1. An offshore floating vessel comprising:
one or more emergency brakes; and
a hoisting system adapted for suspending a load attached to a connecting device of the floating vessel and for lowering or raising a load connected to the connecting device from the floating vessel to or from the sea floor; the hoisting system comprising a drive for moving the connecting device, and the one or more emergency brakes configured to inhibit motion of the connecting device relative to the floating vessel;
wherein the hoisting system is configured to be selectively operated at least in a hoisting mode and in an active heave compensation mode, wherein the hoisting system is configured to perform an active heave compensation when operated in the active heave compensation mode and to operate without active heave compensation when operated in the hoisting mode;
wherein when the hoisting system is operating in either the hoisting mode or in the active heave compensation mode, the one or more emergency brakes are in an enabled mode wherein the one or more emergency brakes operate in a de-energized state where, in the event of a malfunction, the one or more emergency brakes engage so as to inhibit motion of the connecting device relative to the floating vessel, and, when there is no malfunction, the one or more emergency brakes operate in an energized state where the one or more emergency brakes are not engaged and do not inhibit motion of the connecting device relative to the floating vessel;
wherein the hoisting system is further operable in a fixed-to-bottom mode, wherein the hoisting system is configured to perform an active heave compensation, and when the hoisting system is operating in the fixed-to-bottom mode, the one or more emergency brakes are in a non-enabled mode and are prohibited from engaging and cannot inhibit motion of the connecting device relative to the floating vessel.

2. An offshore floating vessel according to claim 1 ; wherein the hoisting system, when operated in the active heave compensation mode, is further adapted to stop active heave compensation responsive to one or more predetermined error conditions; and wherein the hoisting system, when operated in the fixed-to bottom mode, is adapted to maintain active heave compensation despite said one or more predetermined error conditions.

3. An offshore floating vessel according to claim 1 ; comprising a plurality of emergency brakes.

4. An offshore floating vessel, comprising one or more emergency brakes and a hoisting system adapted for suspending a load attached to a connecting device of the floating vessel and for lowering or raising a load connected to the connecting device from the floating vessel to or from the sea floor; the hoisting system comprising a drive for moving the connecting device, and the one or more emergency brakes configured to inhibit motion of the connecting device relative to the floating vessel;
wherein the hoisting system is configured to be operated at least in a hoisting mode and in an active heave compensation mode; wherein the hoisting system is configured to perform an active heave compensation when operated in the active heave compensation mode and to operate without active heave compensation when operated in the hoisting mode;
wherein the one or more emergency brakes are operable in a normally-energized mode including a de-energized state where the one or more emergency brakes engage so as to inhibit motion of the connecting device relative to the floating vessel;
wherein the hoisting system is further operable in a fixed-to-bottom mode; wherein the hoisting system is configured to perform an active heave compensation when operated in the fixed-to-bottom mode; and wherein the hoisting system is adapted to prevent the one or more emergency brakes, at least temporarily, from engaging;
wherein the one or more emergency brakes are hydraulic brakes; wherein the hoisting system comprises a hydraulic system configured to maintain the one or more emergency brakes in a disengaged state by applying a hydraulic pressure to each of said emergency brakes by means of a pressurized fluid; wherein the hydraulic system comprises a plurality of accumulator reservoirs for accommodating hydraulic fluid, each accumulator reservoir being in fluid communication with one of the emergency brakes via a respective conduit so as to provide hydraulic pressure to the corresponding emergency brake during a failure of the hydraulic system; wherein each conduit comprises a valve for selectively opening and closing the conduit; and wherein the hoisting system is operable to set each of said valves in an open position only when the hoisting system is operated in the fixed-to-bottom mode.

5. An offshore floating vessel according to claim 4 , wherein each emergency brake is in fluid communication with a separate accumulator reservoir via a first valve, and in fluid communication with a hydraulic system providing operating pressure to the emergency brake via a second valve; wherein the first vale has an open position and a closed position, and wherein the second valve has an open position and a non-return position allowing fluid flow only from the hydraulic system to the emergency brake; wherein the hoisting system is operable to set the first valve in the open position and the second valve in the non-return position when the hoisting system is operated in the fixed-to-bottom mode, and to set the first valve in the closed position and the second valve in the open position when the hoisting system is operated in a mode different from the fixed-to-bottom mode.

6. An offshore floating vessel according to claim 5 , wherein the first valve and the second valve connected to each emergency brake are operationally coupled to each other so as to prevent operation of one of the first and second valves without operating the other valve.

7. An offshore floating vessel according to claim 5 , wherein operation of each of the first and second valves between their respective positions requires an active activation signal.

8. An offshore floating vessel according to claim 1 , wherein the hoisting system further comprises one or more mechanical blocking members associated with each of the emergency brakes, each mechanical blocking member being movable between a first and a second position, wherein each of the mechanical blocking members, when located in its first position, prevents at least one of the emergency brakes from engaging and, when located in its second position, allows the one emergency brake to engage.

9. An offshore floating vessel according to claim 8 , wherein movement of the mechanical block member between its respective first and second positions requires an active activation signal.

10. An offshore floating vessel according to claim 1 , wherein each emergency brake is selectively operable in an enabled state and a disabled state, and wherein the emergency brake is operable to change between said states only responsive to a respective activation signal.

11. An offshore floating vessel according to claim 1 , wherein the hoisting system is operable to change between said fixed-to-bottom mode and at least one other operation mode responsive to a manual remote operating mechanism for back-up/emergency operation.

12. An offshore floating vessel according to claim 4 ; comprising a plurality of emergency brakes.

13. An offshore floating vessel according to claim 1 ; wherein the hoisting system is used in the fixed-to-bottom mode when the load connected to the connecting device is connected to subsea equipment on the sea floor.

14. An offshore floating vessel comprising one or more e

Assignees

• Maersk Drilling As

Inventors

• Holck Jesper

Classifications

• B66C13/06 Primary

  for minimising or preventing longitudinal or transverse swinging of loads · CPC title

• B63B35/4413

  Floating drilling platforms, e.g. carrying water-oil separating devices · CPC title

• B66D3/043

  Block and tackle system with variable number of cable parts · CPC title

• B66C13/02

  Devices for facilitating retrieval of floating objects, e.g. for recovering crafts from water (handling live-boats B63B; salvaging, or hauling-out on slipways, waterborne vessels B63C; winding mechanism controls B66D1/52) · CPC title

• E21B19/09 Primary

  specially adapted for drilling underwater formations from a floating support using heave compensators supporting the drill string · CPC title