Comparison of produced biosurfactants performance in in-situ and ex-situ MEOR: micromodel study

Abstract

In this study, the performance of biosurfactants produced by Enterobacter cloacae (PTCC:1798) and Acintobacter calcoaceticus (PTCC:1318) is investigated and the optimum values of operational parameters such as salinity%, MEOR type, and microorganism type to enhance the recovery from oil reservoirs are introduced. A comparison between ex-situ and in-situ injection in micromodel is also provided and the efficiency of produced biosurfactants in EOR is investigated for the first time in the literature. Experiments were designed using general factorial method in Design Expert software. In order to do that, design of experiment (DOE) followed by experimental flooding tests into a micromodel and response surface methodology (RSM) were employed. According to experimental design, four levels of salt concentration (0, 3%, 6%, and 12%), two levels of injection type (in-situ and ex-situ), and two levels of bacteria species were examined. The experiment results indicate a maximum oil recovery factor of 58% and 54% for in-situ injection obtained by Acintobacter at 3% salinity and Enterobacter at 6% salinity, respectively. The optimum oil recovery factors of 67% and 59% are achieved by ex-situ injection of water-biosurfactant from Acintobacter in CMC condition and 3% salinity and Enterobacter in CMC condition and 6% salinity, respectively.