Method for removing filter cake from a horizontal wellbore using acid foam
A composition and method for removing a filter cake from a horizontal wellbore in a subterranean formation using a composition containing a inorganic or organic acidic material, a cationic fluorocarbon surfactant, an alkyl alcohol, water optionally containing ammonium chloride and at least one of an alkyl polyglycoside and a betaine surfactant to produce a stable foam used to remove filter cake from a horizontal wellbore.
1. A composition for producing a stable acidic foam for use in removing filter cake from a horizontal wellbore in a subterranean formation, the foam being stable at 200° F. for at least about 3 to about 4 hours, the composition consisting essentially of:
a) an acidic material selected from the group consisting of from about 1 to about 20 weight percent of an inorganic acid, from about 1 to about 30 weight percent of an organic acid and mixtures thereof;
b) about 0.05 to about 3 weight percent of a cationic fluorocarbon co-surfactant;
c) about 0.1 to about 4 weight percent of an alkyl alcohol containing from about 4 to about 8 carbon atoms;
d) of about 0.1 to about 4 weight percent of a betaine surfactant and about 0.25 to about 10 weight percent of an alkyl polyglycoside containing alkyl groups containing from about 8 to about 16 carbon atoms and mixtures thereof and;
e) water optionally containing ammonium chloride.
2. The composition of claim 1 wherein the alkyl polyglycoside is present in an amount from about 0.5 to about 2 weight percent.
3. The composition of claim 1 wherein the composition includes the alkyl alcohol in an amount from about 0.1 to about 2 weight percent.
4. The composition of claim 1 wherein the acidic material is an inorganic acid and wherein the inorganic acid is present in an amount from about 3 to about 10 weight percent.
5. The composition of claim 1 wherein the acidic material is an organic acid and is present in an amount from about 5 to about 20 weight percent.
6. The composition of claim 1 wherein the betaine surfactant is selected from the group consisting of fatty acid amido propyl betaines.
7. The composition of claim 1 wherein the organic acid is selected from the group consisting of formic, acetic, propronic and citric acids and combinations thereof.
8. The composition of claim 1 wherein the cationic surfactant fluorocarbon is selected from the group consisting of fluorinated alkyl quaternary ammonium chlorides.
9. The composition of claim 1 wherein the alkyl alcohol is present in an amount from about 0.1 to about 2 weight percent.
10. The composition of claim 1 wherein the betaine surfactant is cocoamido propyl betaine.
11. The composition of claim 1 wherein the combined amounts of the alkyl polyglycoside, betaine surfactant and cationic fluorocarbon quaternary surfactant are 0.5 to about 6 weight percent of the foam.