WERKWIJZE VOOR DE SECUNDAIRE OLIEWINNING ONDER TOEPASSING VAN GEPROPOXYLEERDE, GEETHOXYLEERDE OPPERVLAKTE-ACTIEVE MIDDELEN IN ZEEWATER.

摘要

A process for removing residual oil from the near wellbore area of a subterranean formation adjacent an injection well of a waterflood operation to improve water injectivity comprising injection through said well into said area seawater containing a surfactant having the formula:PPRO(C.sub.3 H.sub.6 O).sub.7 (C.sub.2 H.sub. 4 O). sub.2 YXPPwherein:PPR is a mixture of alkyl groups containing from 12 to 15 carbon atoms,PPY is sulfate group, andPPX is a monovalent cation.P PAfter the treatment to improve water injectivity, the formation is waterflooded.