Process for the cleaning of oil and gas wellbores

Abstract

Disclosed is a process for cleaning wellbore walls, tubing or casings. The process is characterized by (a) preparing an aqueous surfactant composition containing from about 10% to 60% by weight of a mixture of surfactants, the mixture comprising from 10% to 50% by weight of an anionic derivative of an alkylpolyglycoside, from 35% to 80% by weight of an alkylpolyglycoside and from 5% to 25% by weight of an anionic derivative of a fatty alcohol, their balance being 100%; (b) diluting the aqueous surfactant composition in water to form a diluted aqueous surfactant composition and injecting the diluted aqueous surfactant composition into a wellbore containing drilling mud, oily residues or other undesirable deposits; (c) extracting from the wellbore the diluted aqueous surfactant composition containing the drilling mud, oily residues or other undesirable deposits; (d) removing the drilling mud, oily residues or other undesirable deposits from the diluted aqueous surfactant composition; and (e) optionally, re-using the diluted aqueous surfactant composition.

Dependencies are inferred from the claim text.