Foamed gels having selective permeability
AssigneeUnion Oil Company of California
InventorsRichard D. Hutchins, Burton B. Sandiford, Hoai T. Dovan
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Abstract
Pathway-containing foamed gels enhance the recovery of the nonaqueous fluids from subterranean formations by selectively reducing the flow of aqueous fluids with respect to the flow of nonaqueous fluids.
Claims25
A method for selectively reducing the flow of an aqueous fluid with respect to the flow of a nonaqueous fluid in a subterranean formation, the method comprising, in any order, the steps of:
- (a) injecting into at least a portion of a subterranean formation a composition comprising (i) one or more ingredients capable of reacting to form a gel and (ii) a delayed gel degrading agent;
- (b) injecting into at least a portion of the subterranean formation one or more surfactants capable of foaming the composition;
- and
- (c) injecting a gas for foaming the composition into at least a portion of the subterranean formation.
A recovery system comprising:
- (a) a subterranean formation;
- (b) a well penetrating at least a portion of the subterranean formation;
- and
- (c) a foamed gel located in at least a portion of the subterranean formation, at least a portion of the gel having pathways therein and a noncondensable gas being present in at least a portion of the passageways in a sufficient concentration for gas to flow.
A recovery system comprising:
- (a) a subterranean formation;
- (b) a well penetrating at least a portion of the subterranean formation;
- and
- (c) a composition containing (i) one or more ingredients capable of reacting to form a gel, (ii) a surfactant, and (iii) a delayed gel degrading agent located in at least a portion of the well, the concentration of the delayed gel degrading agent in the composition being sufficient to cause syneresis but less than the concentration required to virtually degrade the entire gel.
An enhanced oil recovery process comprising the steps of:
- (a) injecting a first gas into at least a portion of a subterranean formation having a plurality of vertical zones of different gas permeabilities;
- (b) injecting a composition into a subterranean formation through an injection well, (i) the composition comprising (A) one or more ingredients capable of reacting to form a gel, (B) a surfactant, and (C) a delayed gel degrading agent, and being foamed by the first gas to form a foamed gel along at least a portion of the vertical length of a plurality of the different gas permeability zones, (ii) the delay gel degrading agent forming pathways in the gel, and (iii) the pathway-containing gel being capable of selectively reducing the flow of an aqueous fluid with respect to the flow of a nonaqueous fluid;
- and
- (c) subjecting the formation to an enhanced oil recovery process by injecting a fluid into the subterranean formation through the injection well, wherein at least a portion of the injected fluid is a second gas that transverses the pathway-containing foamed gel and enters a plurality of zones of different gas permeability.
A method for selectively reducing the flow of an aqueous fluid with respect to the flow of a nonaqueous fluid in a subterranean formation, the method comprising the steps of:
- (a) injecting into at least a portion of a subterranean formation a composition comprising (i) one or more ingredients capable of reacting to form a gel, (ii) a delayed gel degrading agent, and (iii) one or more ingredients capable of foaming the composition;
- and
- (b) injecting a gas into at least a portion of the subterranean formation.
A method for selectively reducing the flow of an aqueous fluid with respect to the flow of a nonaqueous fluid in a subterranean formation, the method comprising, in any order, the steps of:
- (a) injecting into at least a portion of a well penetrating at least a portion of a subterranean formation a composition comprising (i) one or more ingredients capable of reacting to form a gel and (ii) a delayed gel degrading agent;
- (b) injecting into at least a portion of the well one or more surfactants;
- and
- (c) injecting a gas for forming a foamed gel into at least a portion of the well.
Dependencies are inferred from the claim text.