Salem Unit Micellar/Polymer Project

Abstract

Texaco, as operator of the Salem Unit, Marion County, Illinois, is conducting a 60 acre semi-commercial tertiary recovery project in the watered out Benoist sandstone. This paper discusses field design and implementation of the project as well as results to date. An extensive field testing program preceeded initial injection. The process used is the Texaco developed brine tolerant surfactant system followed by a biopolymer. Application of this process field-wide in the Benoist reservoir at Salem is anticipated to have a tertiary oil target of 50 million barrels. The project demonstrates a process which extends greatly the reservoir salinity range for which surfactant systems have application. The surfactant system was successful in mobilizing waterflood residual oil. More importantly, the project demonstrates the capability of designing surfactant systems for use in high brine reservoirs without expensive time consuming pre-flushing or reservoir pre-treatment. Field results indicate problem areas to be: Contacting the reservoir with injected fluids (Volumetric Sweep Efficiency), handling and mixing of viscous injectants, treating produced emulsions, obtaining accurate well tests, and bacteria control in biopolymer solutions.