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. 20, 1993
Filed:
Nov. 23, 1992
Stefano C Crema, Ypsilanti, MI (US);
Clare H Kucera, Tulsa, OK (US);
Gerd Konrad, Limburgerhof, DE;
Heinrich Hartmann, Limburgerhof, DE;
BASF Corporation, Parsippany, NJ (US);
Abstract
A cementing composition useful in cementing oil, gas and water wells, comprising water, hydraulic cement and an effective amount of water soluble fluid loss additive comprised of a blend of a copolymer (i) of acrylamide/vinyl imidazole in a weight percent ratio of from about 95:5 to 5:95, said copolymer (i) having a molecular weight range of from about 100,000 to 3,000,000, and a copolymer (ii) of vinyl pyrrolidone and the sodium salt of vinyl sulfonate in a weight percent ratio of 80:20 to 20:80, said copolymer (ii) having a molecular weight range of from about 100,000 to 3,000,000. The blend is comprised of a weight percent ratio of copolymer (i) to copolymer (ii) in the range of 20:80 to 80:20. The composition can also optionally include a dispersant such as sodium or potassium salts or a sulfonated naphthalene formaldehyde condensate.