Delayed gelation of polymers
AssigneesConocoPhillips Company, University of Kansas
InventorsHuili Guan, Cory Berkland, Ahmad Moradi-Araghi, Jenn-Tai Liang, Terry M. Christian, Riley B. Needham, Min Cheng
Life of this patent
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Abstract
The disclosure is directed to methods and compositions delaying the gelation of polymers in water flooding by sequentially or co-injecting a carboxylate-containing polymer solution, a gel-delaying polymer, and gelation agent into a hydrocarbon reservoir. Delays of weeks are observed.
Claims26
A method of increasing the recovery of hydrocarbon fluids in a subterranean formation comprising:
- a) sequentially injecting a carboxylate-containing polymer, at least one gel-delaying polymer, and a crosslinker into an in-line mixer to form a gelling solution comprising a carboxylate-containing polymer-gel-delaying polymer-crosslinker complex;
- b) mixing said gelling solution in said in-line mixer;
- and,
- c) injecting said gelling solution into said subterranean formation;
- wherein said gel-delaying polymer delays the gelation of said carboxylate-containing polymer by said crosslinker in said subterranean formation.
An improved method of sweeping for oil or gas, said method requiring blocking thief zones with a polymer, and sweeping a reservoir for oil or gas, the improvement comprising:
- a) injecting into a reservoir, in order:
- i) a carboxylate-containing polymer,
- ii) at least one gel-delaying polymer, and
- iii) a crosslinker,
- to form a gelling composition without forming a separate nanogel between the at least one gel-delaying polymer and crosslinker first:
- b) aging said composition until the viscosity increases;
- and,
- c) sweeping the reservoir for oil or gas.
An improved method of producing oil or gas, said method requiring injecting a polymer into a reservoir and producing an oil or gas, the improvement comprising:
- a) injecting into a reservoir, in order:
- i) a carboxylate-containing polymer,
- ii) at least one gel-delaying polymer, and
- iii) a crosslinker into a reservoir,
- to form a gelling composition without forming a separate nanogel between the at least one gel-delaying polymer and crosslinker first;
- b) aging said composition for at least 35 days at 85° C. until the viscosity increases;
- and
- c) producing said oil or gas.
Dependencies are inferred from the claim text.