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US 4,305,468 AGranted
Method for drilling wellbores from an offshore platform
AssigneeConoco Inc.
InventorRiley G. Goldsmith
Life of this patent
Estimating the term…
Abstract
A method for drilling wellbores from an offshore platform to penetrate a subterranean formation using a combination of surface drilling techniques and subsea drilling techniques to achieve an improved effectiveness by avoiding the necessity for large conduits communicating the ocean floor and the offshore platform.
Claims14
A method of drilling a borehole from an offshore platform through an ocean floor to penetrate a subterranean formation, said method comprising:
- (a) drilling an uncased borehole into said ocean floor;
- (b) casing said borehole;
- (c) terminating said casing near said ocean floor;
- (d) positioning a high pressure drilling riser having an outer diameter less than an outer diameter of an outer casing string of said casing in fluid communication with at least one casing string of said casing and said platform;
- (e) positioning a blowout preventor near a top of said high pressure drilling riser for containing in said high pressure drilling riser any high pressures produced by said subterranean formation;
- (f) drilling another portion of said borehole through said blowout preventor and said drilling riser to penetrate said subterranean formation;
- and,
- (g) casing said other portion of said borehole to a selected depth with the casing terminating near said ocean floor.
5 more elements
Dependencies are inferred from the claim text.