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U.S. Department of Energy
Office of Scientific and Technical Information

Treating wells with a temporarily thickening cellulose ether solution

Patent ·
OSTI ID:6638032
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 either dispersed in aqueous liquid solutions of buffering agents, pH- increasing 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. (9 claims)
Assignee:
Shell Oil Co.
Patent Number(s):
US 4026361
OSTI ID:
6638032
Country of Publication:
United States
Language:
English