Cantilever supported drilling rig

• US 6,481,931 B1
• Filed: 09/19/2000
• Issued: 11/19/2002
• Est. Priority Date: 09/19/2000
• Status: Expired due to Term

• Current Assignee: Loadmaster Derrick & Equipment, Inc.
• Original Assignee: Walter Thomas Welsh
• Inventors: Welsh, Walter Thomas
• Primary Examiner(s): Shackelford, Heather
• Assistant Examiner(s): LAGMAN, FREDERICK LYNDON
• Application Number:
  US09/665,023
• Time in Patent Office: 791 Days
• Field of Search: 405/201, 405/203, 405/204, 405/200, 405/199, 405/198, 405/197, 405/196, 405/195.1, 175/5, 175/7, 175/8, 175/9
• US Class Current: 405/201
• CPC Class Codes: E21B 15/02 specially adapted for underwater drilling E21B15/04 takes precedence

Abstract

The derrick is configured to place the lift axis of the crown block toward the aft end of the rig floor. Major floor loads such as draw works are moved closer to the platform. The spare line spool support is changed from rig floor to platform. The set back areas are distributed on both sides of the vee door.

Claims

1. A combination derrick adaptation and a drilling floor plan for a cantilever supported drilling rig having a fore end adjacent a supporting hull, and an aft end, a port side and a starboard side, with a vee door at the fore end, arranged for a main hoist hook load axis extending through said floor, the combination comprising:

a) set back areas for racked pipe on each transverse side of the vee door, on the fore end of said floor;

b) draw works on the port side of said floor;

c) dynamic brake at the fore end of the draw works;

d) drillers station aft of the draw works, on the port side;

e) spare line spool on the hull; and

f) said derrick extending upward from the floor and arranged to suspend a drill string along the well centerline about one third of the floor length from the aft end.

2. The combination of claim 1 wherein said draw works is a Varco AC drive three thousand to five thousand horsepower unit.

3. The combination of claim 1 wherein the aft end of said draw works is at least eight feet forward of the aft end of the rig floor.

4. The combination of claim 1 wherein said set back areas are divided into three separate sub-areas, a first sub-area on the port side of the vee door, a second sub-area on the starboard side of the vee door, and a third sub-area having less transverse dimension than said second sub-area situated aft of said second sub-area.