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:
May. 06, 2003
Filed:
Nov. 21, 2001
Stuart E. Lebo, Jr., Ringle, WI (US);
Shane L. Resch, Schofield, WI (US);
Lignotech USA, Inc., Rothschild, WI (US);
Abstract
An improved non-dispersing set retarder additive for foamed cements, cement compositions containing the additive, and methods of cementing in a subterranean zone penetrated by a well bore are provided. The set retarder additive includes a blend of a sulfonated lignin, preferably a lignosulfonate, with an alkali lignin, preferably a kraft lignin, having an organic sulfur content of 0-3.5% by weight in a ratio of about 6:4 to 8:2. The methods are basically comprised of the steps of preparing a foamed cement composition comprised of hydraulic cement, a non-dispersing set retarder, sufficient water to form a slurry, sufficient gas to foam the slurry and a foaming and foam stabilizing surfactant present in an amount sufficient to facilitate the formation of the foam and stabilize the foamed cement composition.