Different approach to surfactant screening methods for ASP flooding

Abstract

Selection of adequate surfactant is one of the most important steps in preparation for ASP EOR. There are many parameters to be taken in considerations in this process but different authors are prioritizing different parameters. Shown here is comparative analysis of two surfactants chosen according difference set of priorities, in one low IFT and stability and type of created microemulsion was priority (Surfactant A) and in another mobility of created microemulsion (Surfactant B). Bottle test was done with both surfactants to assess the stability of microemulsion at formation temperature, and coreflood test to assess ability of surfactant to mobilize trapped oil. During first round of tests Surfactant A gave better results, very low IFT and stabile Windsor type III microemulsion while Surfactant B gave higher IFT and Windsor type I microemulsion. During coreflood test Surfactant B performed better in terms of oil recovery factor (ORF) and injection pressures. Apparently, stabile Windsor type III microemulsion that is considered desirable in ASP injection and widely prioritized in surfactant selection process can cause decrease in permeability and injectivity issues. Good results can be obtained with IFT in “moderately” low range and stability of microemulsion is not critical in terms of oil recovery factor.