Design and Application of an Alkaline‐Surfactant‐Polymer Flooding System in Field Pilot Test

We have developed an inexpensive sort of flooding reagent whose major components are natural mixed carboxylates from proportionally mixed saponification residuals of cottonseed oil, tea oil, vegetable oil, and soybean oil. An orthogonal test design method was used to select one form of this flooding reagent (which is named SD) by measuring the phase behavior and another form of the flooding system: alkaline/surfactant/polymer (named SD‐ASP). The optimal composition was obtained by measuring the transient interfacial tension (IFT) at the crude oil/aqueous interface. Results of the tests show that the SD‐ASP flooding systems are tolerant to salt up to 1.5×105 mg/L and to Ca2+ and Mg2+ to 5.0×103 mg/L at 90°C, the IFTmin (the minimum of IFT) is 10−3 mN/m, and the oil recovery ratio reaches 22.77% by using the core flood experiment. The pilot tests, including a putting in and sending out in a single oil well, a group oil well and a larger well region, were all very successful, with an average input‐output rat...