Petroleum recovery using ternary surfactant systems - from formations contg. high concns of polyvalent ions

摘要

Ternary surfactant system for use in recovery of petroleum from underground formations in which formation water contains 1500-12000 ppm polyvalent ions comprises (a) first anionic surfactant chosen from water soluble salts of alkyl and alkylaryl sulphonates (where alkyl groups contain 5-25 (8-14) C atoms), (b) second anionic surfactant chosen from water soluble salts of alkyl polyethoxy sulphates (1-10 ethoxy groups and alkyl contains 7-20 (8-14) C atoms), and (c) a nonionic surfactant chosen from polyethoxylated 5-20 (8-14) C alkyl phenols and 5-20 C aliphatic alcohols (each contg. 6-20 (9-10 polyethoxy groups), and fatty acid mono and dialkanolamides fatty acid contg. 5-20 C atoms). Each of a) and (b) contains Na, K or NH4 cations, concn. of each surfactant is 0.05-5% wt (pref. 0.2-5% wt), and ratio (a) to (c) is 1-4. Pref. (a) are ammonium salts of dodecyl-and lauryl-benzene sulphonates, or petroleum sulphonates, pref. (b) is sodium dodecyl polyethoxy sulphate, and pref. (c) includes polyethoxylated nonylphenol, lauryldiethanolamide, dodecyldiisopropanolamide and dodecylmonoethanolamide. In the pref. operation a hydrophilic polymer (polyacrylamide or polysaccharide) is added to the surfactant compsn. or is injected after the surfactant compsn. to increase the viscosity.