Summary
A tertiary alkaline/surfactant/polymer (ASP) pilot flood was implemented during 2010 in the Illinois basin of the US, and is continuing currently. With initial discovery of the Bridgeport sandstone formation in the early 1900s and more than 60 years of waterflooding, the pilot was designed to demonstrate that ASP flooding could produce sufficient quantities of incremental oil to sanction a commercial project. Laboratory experiments, including corefloods, were performed to determine the optimal chemical formulation for the pilot and to provide essential parameters for a numerical-simulation model. Polymer-injectivity tests, single well chemical tracer tests (SWCTTs), and an interwell-tracer-test (IWTT) program were all performed to prepare for and support a full interpretation of the pilot results. A field laboratory was run through the duration of the pilot to monitor the quality of the injection and production fluids, which turned out to be critical to the success of the pilot. We present the results and interpretation of the ASP pilot to date, the challenges faced during the project, and the lessons learned from the field perspective.
