Development of Supersurfactant for Enhanced Oil Recovery Application

Surfactant flooding is a form of chemical enhanced oil recovery (EOR) that can allow operators to extend reservoir pool life and extract incremental reserves currently inaccessible by conventional EOR techniques such as water flooding. A very low concentration of the surfactant can be used to achieve ultra low interfacial tension between the trapped oil and the injection fluid/formation water.
Addition of a surfactant lowers the interfacial tension between water and oil which helps to reduce capillary pressure in the reservoir. Many petroleum formations contain water having high salinity and are additionally at temperature from about 30°C to about 150°C. Most surfactants suitable for use in oil recovery operations are either not effective in high salinity or cannot tolerate the higher temperatures encountered in many such formations.
The objective of this research was to develop a systematic laboratory screening and design a high performance chemical formulation that can be used for challenging reservoirs that have high salinity and also high temperature. Aqueous and microemulsion phase behavior tests have previously been shown to be a rapid, inexpensive and highly effective means to select the best chemicals and minimize the need for relatively expensive core flood tests. Aqueous stability test, interfacial tension (IFT) measurement and phase behavior tests were therefore done with various combinations of surfactants and alkali for several reservoir conditions including the challenging reservoir of interest which is Dulang Oil Field. Extensive laboratory screening identified potential chemical formulations that give the lowest IFT for the targeted reservoir.