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U.S. Department of Energy
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Process for cleaning a subterranean injection surface and for selectively reducing the permeability of a subterranean formation

Patent ·
OSTI ID:5907290

A process is described for selectively reducing the permeability of a subterranean formation while intermittently cleaning a subterranean injection surface plugged with a crosslinked dry polymer. An aqueous solution containing an oxidizing agent is injected into a well bore penetrating and in fluid communication with the formation. The oxidizing agent reacts with the crosslinked polymer to clean the injection surface while concomitantly providing a cationic crosslinking agent for subsequent reaction in the formation. An aqueous spacer medium is injected via the well bore to flush the products of such reaction, including the cationic crosslinking agent, into the formation. Subsequently, injection into the formation of an aqueous solution having a dry polymer dissolved therein is continued. The polymer is crosslinked in situ by the cationic crosslinking agent to form a plugging gel. Examples of the oxidizing agent and the polymer are, respectively, sodium dichromate and polyacrylamide.

Assignee:
Marathon Oil Co.
Patent Number(s):
US 4343363
OSTI ID:
5907290
Country of Publication:
United States
Language:
English