METHOD FOR STIMULATING WELL PRODUCTION

摘要

1482838 Stimulating well production TEXACO DEVELOPMENT CORP 20 Oct 1975 [20 Dec 1974 (8)] 42952/75 Heading E1F A method of acidizing a subterranean formation comprises injecting into the formation an aqueous acid solution including from 0.5 to 28% by weight of a non-oxidizing mineral acid, e.g. hydrochloric acid, or from 0.01 to 5% by weight of carbon dioxide, and from 0.005 to 2% by weight of a sulphonated antiscale compound of the formula X-SO 3 - A+ wherein A+ is an alkali metal or ammonium ion, and X is a group of the formula R-[-OCH 2 CH 2 -]- n or R 2 -CO-NR 1 - CH 2 CH 2 - in which R is an alkaryl group having 6 to 18 carbon atoms in its alkyl moiety, or a saturated or unsaturated aliphatic hydrocarbon group having 8 to 20 carbon atoms, n is a number from 1 to 10, and R 1 and R 2 which may be the same or different, are each a saturated or unsaturated aliphatic hydrocarbon group containing up to 20 carbon atoms, the total number of carbon atoms in R 1 and R 2 being from 9 to 30. Compounds to inhibit the corrosion of metal, e.g. arsenic, nitrogen or sulphur compounds, and to retard the tendency of the acid to attack calcareous components of the formation, e.g. polyvinyl-pyrrolidone, may be present. The acidizing method may be carried out at pressures sufficient to fracture the formation with the acid solution containing a propping agent, e.g. sand. The acid solution may be continuously or temporarily injected into the formation or may be applied in a modified water flood operation in which there is injected into the formation a slug of the acid solution followed by a slug of aqueous drive fluid, which is thereafter followed by a repetition of the two steps to give a continuous cyclic process.