Ultra-high temperature stable gels
AssigneeUnion Oil Company of California
InventorsRichard D. Hutchins, Hoai T. Dovan, Burton B. Sandiford
Life of this patent
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Abstract
Cationic polymer-containing gels are stable at elevated temperatures in soft and hard waters.
Claims29
A method for forming a gel in at least a portion of a subterranean formation, the method comprising the steps of:
- (A) injecting a composition into at least a portion of a subterranean formation, the composition comprising (i) water and (ii) a water soluble, crosslinkable polymer comprising an (.alpha.) acrylamide unit having the formula I ##STR6## and (.beta.) a cationic unit having the formula II ##STR7## where Z is an anion, R.sub.1 and R.sub.2 are independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 10 carbon atoms, the mole fraction of acrylamide units present in the polymer is less than 0.5, and the mole fraction of cationic units present in the polymer is at least 0.5, provided that the total sum of these mole fractions is 1;
- and
- (B) injecting a crosslinking agent into at least a portion of the subterranean formation.
A method for forming a gel in at least a portion of a subterranean formation, the method comprising the step of injecting a composition into at least a portion of a subterranean formation, the composition comprising (A) water, (B) a crosslinking agent, and (C) a water soluble, crosslinkable polymer comprising an (.alpha.) acrylamide unit having the formula I ##STR8## and (.beta.) a cationic unit having the formula II ##STR9## where Z is an anion, R.sub.1 and R.sub.2 are independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 10 carbon atoms, the mole fraction of acrylamide units present in the polymer is less than 0.5, and the mole fraction of cationic units present in the polymer is at least 0.5, provided that the total sum of these mole fractions is 1.
A recovery system comprising:
- (a) a subterranean formation;
- (b) a well penetrating at least a portion of the subterranean formation;
- and
- (c) a gel located in at least a portion of the subterranean formation, where the gel comprises:
- (i) water;
- and
- (ii) a crosslinked polymer, the polymer comprising an (.alpha.) acrylamide unit having the formula I ##STR10## and (.beta.) a cationic unit having the formula II ##STR11## where Z is an anion, R.sub.1 and R.sub.2 are independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 10 carbon atoms, the mole fraction of acrylamide units present in the polymer is less than 0.5, and the mole fraction of cationic units present in the polymer is at least 0.5, provided that the total sum of these mole fractions is 1.
A recovery system comprising:
- (a) a subterranean formation;
- (b) a well penetrating at least a portion of the subterranean formation;
- and
- (c) a composition located in at least a portion of the well, where the composition comprises:
- (i) a polymer comprising an (.alpha.) acrylamide unit having the formula I ##STR12## and (.beta.) a cationic unit having the formula II ##STR13## where Z is an anion, R.sub.1 and R.sub.2 are independently selected from the group consisting of hydrogen and alkyl groups containing 1 to 10 carbon atoms, the mole fraction of acrylamide units present in the polymer is less than 0.5, and the mole fraction of cationic units present in the polymer is at least 0.5, provided that the total sum of these mole fractions is 1;
- (ii) a crosslinking agent;
- and
- (iii) water.
Dependencies are inferred from the claim text.