The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 29, 1981
Filed:
Mar. 25, 1980
Applicant:
Inventor:
Pierre A Beynet, Tulsa, OK (US);
Assignee:
Standard Oil Company (Indiana), Chicago, IL (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ; E21B / ; E21B / ;
U.S. Cl.
CPC ...
175-5 ; 175-7 ; 175 38 ; 175 40 ; 175 25 ;
Abstract
Method and apparatus are described to reduce the tension required on a riser pipe used in offshore drilling between a floating vessel and a subsea wellhead. Heavy drilling fluid is circulated down a drill pipe and up the annulus between the drill pipe and the borehole wall to a point just above a subsea wellhead. From this point, a separate drilling fluid return conduit extends to the floating vessel. Means are provided to maintain a constant level of an interface between the heavy returning drilling fluid and the lightweight fluid which can be confined within the riser pipe.