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:
Apr. 07, 1992
Filed:
Oct. 05, 1990
Applicant:
Inventors:
Charles O Stockley, Houston, TX (US);
Richard C Haas, Corpus Christi, TX (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
175 65 ; 175195 ; 175214 ; 175215 ;
Abstract
Method and apparatus for drilling wells in which the annulus between the casing and drill string is sealed below the kelly and blowout preventers and drilling fluid returns are conducted from below the seal to the exterior through the drilling head. The annulus may be controlled below the seal to permit lubricating the seal through the blowout preventers while maintaining the well under complete control. A surface controlled subsurface valve may control drilling fluid returns.