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|1. (WO2018219654) METHOD FOR EXTRACTING PETROLEUM FROM UNDERGROUND DEPOSITS HAVING HIGH TEMPERATURE AND SALINITY|
WINTERSHALL HOLDING GMBH
|Title:||METHOD FOR EXTRACTING PETROLEUM FROM UNDERGROUND DEPOSITS HAVING HIGH TEMPERATURE AND SALINITY|
The invention relates to a method for extracting petroleum from underground oil reservoirs, wherein an aqueous, salt-containing surfactant formulation comprising a surfactant mixture for lowering the interfacial tension between oil and water to < 0.1 mN/m is pressed into an oil reservoir through at least one injection well and crude oil is removed from the reservoir through at least one production well, wherein the oil reservoir has a temperature of ≥ 90°C and a formation water having a salinity of ≥ 30000 ppm of dissolved salts and wherein the surfactant mixture contains at least one ionic surfactant (A) of general formula (I): (R1)k-N+(R2)(3-k)R3 (X-)l and at least one anionic surfactant (B) of general formula (II): R4-O-(CH2C(R5)HO)m-(CH2C(CH3)HO)n-(CH2CH2O)o-(CH2)p-Y-M+, wherein, during injection, there is a molar ratio of ionic surfactant (A) to anionic surfactant (B) of 90 : 10 to 10 : 90 in the surfactant mixture and wherein R1 to R5, k, l, m, n, o, p, X, Y and M have the meaning indicated in the claims and in the description. The invention further relates to a concentrate containing surfactant (A), surfactant (B), or the surfactant mixture.