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. 31, 1977
Filed:
Jun. 14, 1976
Randolph H Knapp, Houston, TX (US);
Edwin A Richardson, Houston, TX (US);
Shell Oil Company, Houston, TX (US);
Abstract
In well treatments such as workovers, fracturing processes, etc., permeable subterranean earth formations are temporarily plugged by contacting them with self thickening-and-thinning liquid systems. The systems initially contain unhydrated cellulose ether dispersed in aqueous liquid solutions of buffering agents, pH-increasing reactants and pH-decreasing reactants. The system components are arranged so that the cellulose ether hydration is first delayed by a buffer-maintained acidity, then is accelerated by an increasing pH and, subsequently, the high viscosity due to the dissolved hydrated cellulose ether is reduced by an acid-induced hydrolysis of the ether.