Evaluation of a Composite Flooding Formula Used to Enhance the Oil Recovery of Ansai Oil Field

摘要

The composite flooding formula utilizes the characteristics of polymer flooding and surfactant flooding to compensate for the shortage of single component chemical flooding, reduce the oil-water interfacial tension to a certain extent, and broaden the maintenance range of low interfacial tension. The combined effects and synergies in the oil displacement process enhance oil recovery and allow it to adapt to a wider range of reservoir conditions. In this paper, the high surface active polymer-surfactant flooding formula suitable for the Chang 6 reservoir in Ansai Oilfield was evaluated. The general technical index of the viscoelastic surfactant fracturing fluid and the composite flooding surfactant were evaluated. The technical requirements are evaluation criteria, and comprehensive evaluation is made from several aspects such as salt tolerance, interfacial tension and emulsifying properties.