Product and process for acid diversion in the treatment of subterranean formations
AssigneeDowell Schlumberger Incorporated
InventorMohamed Zerhboub
Life of this patent
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Abstract
The invention relates to the treatment by a fluid, or more generally by an acid fluid, of subterranean formations located in particular around an oil, gas, water or geothermal well. Acid is diverted towards the zone to be treated by a surfactant flush, the injection of a foam and then the injection of an acid/surfactant composition. These operations are repeated as often as required, increasing at each stage representing approximately 80 cm (20 to 25 inches) of treatment in terms of height the quantity of foam injected.
Claims7
A process for treating a relatively low permeability first zone of a subterranean formation having at least one adjacent second zone of relatively higher permeability penetrated by a well to the subterranean formation comprising steps of:
- (a) injecting a foam comprising an inert fluid, a gas and at least one surfactant into the subterranean formation followed by the step of
- (b) injecting a treatment fluid into the subterranean formation, the treatment fluid comprising an active fluid and at least one surfactant contained in the foam and
- (c) repeating said sequential foam and treatment fluid injecting steps (a) and (b) using an increasing volume of foam in each subsequent foam injecting step whereby the treatment fluid is diverted toward the first zone.
A process for treating a relatively low permeability first zone of a subterranean formation having at least one adjacent second zone of higher permeability penetrated by a well to the subterranean formation comprising the steps of:
- (a) injecting a foam comprising an inert fluid, a gas and a surfactant comprising a sodium/formaldehyde polynaphthalene-sulfonate condensation product into the subterranean formation followed by the step of
- (b) injecting a treatment fluid into the subterranean formation, the treatment fluid comprising a diluted acid and a surfactant comprising a sodium/formaldehyde polynaphthalene-sulfonate condensation product and
- (c) repeating said sequential foam and treatment fluid injecting steps (a) and (b) using an increasing volume of foam in each subsequent foam injecting step.
Dependencies are inferred from the claim text.