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:
Jan. 29, 1991
Filed:
Mar. 03, 1989
Applicant:
Inventors:
James A Wingrave, Chadds Ford, PA (US);
Thomas S Carter, Spring, TX (US);
Charles F Palmer, Jr, Christiana, DE (US);
Assignee:
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C09K / ; E21B / ;
U.S. Cl.
CPC ...
252-8514 ; 175 65 ;
Abstract
Additive compositions and aqueous drilling fluids which impart improved wellbore stability in drilling shale formations consisting essentially of one or more water-soluble high molecular weight polymers capable of forming relatively strong nucleophilic sites when treated with base and one or more potassium salts which have sufficient alkalinity to raise the pH of the resultant drilling fluid to above 9.0, but whose anions are relatively weak nucleophiles compared to the polymeric nucleophilic sites.