Multiple activity rig

• US 8,678,094 B2
• Filed: 06/01/2005
• Issued: 03/25/2014
• Est. Priority Date: 06/02/2004
• Status: Expired due to Fees

• Current Assignee: Stena Drilling Limited (Stena Sphere)
• Original Assignee: Stena Drilling Limited (Stena Sphere)
• Inventors: Banks, John
• Primary Examiner(s): BUCK, MATTHEW R
• Application Number:
  US11/597,016
• Publication Number:
  US 20070251725A1
• Time in Patent Office: 3,219 Days
• Field of Search: 166/344, 166338-341, 166358-360, 166366-368, 166/352, 175 5- 10, 405/184.4, 405/201, 405/224.2, 414 2251- 2271
• US Class Current: 166/352
• CPC Class Codes: E21B 19/002 specially adapted for underwater drilling E21B19/09, E21B19/143 take precedence
• CPC Class Codes: E21B 19/004 supporting a riser from a drilling or production platform
• CPC Class Codes: E21B 19/14 Racks, ramps, troughs or bins, for holding the lengths of rod singly or connected; Handling between storage place and borehole E21B19/20, E21B19/22 take precedence
• CPC Class Codes: E21B 19/143 specially adapted for underwater drilling

Abstract

An offshore platform may include a pair of trolleys. One trolley may be mounted on top of the platform and the other trolley may be suspended below the platform. Each trolley may be positioned on opposed sides of a moon pool in one embodiment of the present invention. The lower trolley may be used to hang off a riser and blowout preventer. The upper trolley may be utilized to hang off smaller diameter casing while larger diameter casing is being made up and positioned within the hole. As a result of the parallel operations made possible by the trolleys, drilling time may be reduced in some embodiments.

Claims

1. A method comprising:

hanging off a first casing from a trolley mounted on an offshore drilling platform;

positioning a second casing having a larger diameter than the first casing without using said trolley when said first casing is hanging off from the trolley;

repositioning the first casing by rolling the trolley into a position over the second casing when the second casing is in position within the seabed floor;

jetting in the second casing; and

inserting a drill string through the second casing to drill a hole for the first casing.

2. The method of claim 1 including lowering the first casing into the hole below the second casing.

3. The method of claim 1 including hanging off a blowout preventer and riser from said platform.

4. The method of claim 3 including hanging off said blowout preventer and riser from a lower trolley on said platform while hanging off said first casing from said trolley mounted on said platform and positioning said second casing.

5. The method of claim 4 including providing an extension on a moon pool in said platform and providing a mating extension on said trolley mounted on said platform to enable said first casing to be lifted from said moon pool extension and positioned over said moon pool.

6. A method comprising:

hanging off a first casing from a trolley mounted on an offshore drilling platform;

positioning a second casing having a larger diameter than the first casing without using said trolley when said first casing is hanging off from the trolley;

repositioning the first casing by rolling the trolley into a position over the second casing when the second casing is in position within the seabed floor;

hanging off a blowout preventer and riser from said platform; and

hanging off said blowout preventer and riser from a lower trolley on said platform while hanging off said first casing from said trolley mounted on said platform and positioning said second casing.

7. The method of claim 6 including jetting in the second casing.

8. The method of claim 7 including inserting a drill string through the second casing to drill a hole for the first casing.

9. The method of claim 8 including lowering the first casing into the hole below the second casing.

10. The method of claim 9 including providing an extension on a moon pool in said platform and providing a mating extension on said trolley mounted on said platform to enable said first casing to be lifted from said moon pool extension and positioned over said moon pool.