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:
Oct. 20, 1992
Filed:
Dec. 17, 1990
Dennis H Hoskin, Lawrenceville, NJ (US);
Thomas R Sifferman, Plano, TX (US);
Mobil Oil Corporation, Fairfax, VA (US);
Abstract
A method for imparting selectivity to an in-situ gel-forming composition for placement within a subterranean oil-bearing formation having relatively high permeability zones and relatively low permeability zones, comprising the steps of: preparing an aqueous-based mixture, the mixture comprising: a first stage gel-forming composition in an amount effective to selectively enter the relatively high permeability zones of the formation, the first stage composition including a heteropolysaccharide prepared by growing Xanthomonas campestris NCIB 11854 in an aqueous nutrient medium by aerobic fermentation and recovering the heteropolysaccharide and a crosslinking agent for the heteropolysaccharide; and at least one second stage in-situ gel-forming composition comprising a water-dispersible polymer and a crosslinking agent for the water-dispersible polymer in an amount effective to form a stable gel; and gelling the first stage gel-forming composition ex-situ by reacting the Xanthomonas campestris NCIB 11854 heteropolysaccharide with the crosslinking agent for the heteropolysaccharide. The mixture so prepared exhibits greater selectivity than would a like mixture in the absence of the first stage selective gel-forming composition.