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:
Jul. 15, 1986
Filed:
Sep. 12, 1984
Applicant:
Inventors:
Patricia A Gleason, Westfield, NJ (US);
Chester D Szymanski, Martinsville, NJ (US);
Assignee:
National Starch and Chemical Corporation, Bridgewater, NJ (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C09K / ;
U.S. Cl.
CPC ...
252 / ; 252 / ;
Abstract
Low and high solids drilling fluids containing high levels (i.e., at least 10,000 ppm) of divalent cations are provided with improved fluid loss control by employing high molecular weight water-in-oil emulsion copolymers of acrylamide and a water soluble salt of acrylic acid. The copolymers, produced by the copolymerization in water-in-oil emulsions form of acrylamide and acrylic acid or the salt thereof in molar ratios of 70:30 to 95:5 are particularly effective in drilling fluids containing high levels of calcium ions.