Flywheel-based energy storage on a heave-compensating drawworks

• US 7,633,248 B1
• Filed: 05/18/2007
• Issued: 12/15/2009
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Nabors Drillling Technologies USA, Inc.
• Original Assignee: Kevin R. Williams
• Inventors: Williams, Kevin R.
• Primary Examiner(s): Ro; Bentsu
• Application Number:
  US11/750,837
• Time in Patent Office: 942 Days
• Field of Search: 318/140, 318/150, 318/161
• US Class Current: 318/150
• CPC Class Codes: E21B 19/006 including heave compensators
• CPC Class Codes: E21B 19/09 specially adapted for drilling underwater formations from a floating support using heave compensators supporting the drill string
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes
• CPC Class Codes: H02K 7/025 for power storage
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A system for managing energy consumption in a heave-compensating drawworks includes a power supply, a winch drum connected to the power supply so as to receive power from the power supply, a flywheel connected to the winch drum and to the power supply, and a controller connected to the power supply and to the winch drum for passing energy to and from the flywheel during an operation of the winch drum. The flywheel includes a disk rotatably coupled to an AC motor. The power supply includes a first pair of AC motors operatively connected on one side of the winch drum and a second pair of AC motors operatively connected on an opposite side of the winch drum.

Claims

1. A process of managing energy consumption in a drawworks, the drawworks having a winch drum with a wire rope therearound, the winch drum extending around a sheave assembly and connected to a drill string, the process comprising:

rotating the winch drum so as to pay out the wire rope and to lower the drill string downwardly;

transferring the energy from the lowered drill string to a flywheel so as to rotate said flywheel;

transferring energy from the rotating flywheel to another location on the drawworks; and

compensating for heave of the drawworks by rotating said winch drum in relation to a movement of the drawworks in relation to wave motion.

2. The process of claim 1, said step of transferring energy from the rotating flywheel comprising:

transferring energy from the rotating flywheel to the winch drum; and

raising the drill string by paying in the wire rope over the winch drum.

3. The process of claim 1, further comprising:

connecting an AC motor to the winch drum so as to apply rotational forces to the winch drum; and

connecting another AC motor to the flywheel.

4. The process of claim 3, said step of connecting an AC motor comprising:

coupling said winch drum to a first AC motor by a shaft on one side of said winch drum; and

coupling said winch drum to a second AC motor by said shaft on an opposite side of said winch drum.

5. The process of claim 1, said step of transferring energy from the lowered drill string comprising:

transferring energy from the AC motor connected to the winch drum to said another AC motor connected to the flywheel.

6. A process of managing energy consumption in a drawworks, the drawworks having a winch drum with a wire rope therearound, the winch drum extending around a sheave assembly and connected to a drill string, the process comprising:

rotating the winch drum so as to pay out the wire rope and to lower the drill string downwardly;

transferring the energy from the lowered drill string to a flywheel so as to rotate said flywheel;

transferring energy from the rotating flywheel to another location on the drawworks; and

compensating for heave of the drawworks by moving the sheave assembly vertically in relation to the drawworks in response to wave motion.

7. The process of claim 6, said another location being a utility system on the drawworks.

8. The process of claim 7, said drawworks being located on a drill ship, said another location being an engine associated with a thruster of the drill ship.