Foaming Properties and Foam Structure of Produced Liquid in Alkali/Surfactant/Polymer Flooding Production

Abstract

Alkali/surfactant/polymer (ASP) flooding process is proven to be vitally effective for enhancing oil recovery (EOR) in the oil industry. However, foaming behavior is generated by the breakthrough of chemical agents in the produced liquid and is increasingly concerned as a terrible problem during production. A set of experiments were recently performed to investigate the effects of foaming properties of ASP flooding produced liquid. The factors affecting foaming capacity and foam stabilization were discussed, and the differences in foaming properties of produced liquid between the strong base and weak base ASP flooding were first compared. The results indicated that in addition to temperature and pressure, the concentrations of chemical agents in the produced liquid were responsible for the foaming properties and foam stabilization. The foaming capacity could enhance 3–7% at 45 °C compared with a lower temperature of 35 °C. The average comprehensive index of the foam could increase from 2.2 × 105 at 29 psi to 2.5× 105 at 73 psi. The regularity of Plateau borders was highlighted at higher pH and surfactant concentration and thus facilitated the foam stabilization. The liquid film thickened and its shape expanded to the state of maintaining foam stabilization with the increase of polymer concentration. Furthermore, the foaming behavior of produced liquid in strong base ASP flooding production is much-more troublesome than that in weak base ASP flooding production. This study is significant in that it further supports the development of efficient treatment technology for produced liquid in the oilfield.