Biphasic interfacial functioning improvement using naturally derived Hop and Dill surfactants in carbonate reservoirs

Abstract

This study mainly focuses on the application of environmentally friendly surfactants in enhanced oil recovery (EOR). Two natural and environmentally friendly surfactants of Hop and Dill were introduced to observe their visions of fluid/fluid/rock interfacial activity of surfactant solutions as ion tuned EOR method. Investigations of interfacial tension (IFT) reduction and wettability alteration toward a water-wetting tendency were conducted to evaluate the improvement of oil recovery factor. Dynamic displacement tests of carbonate porous medium flooding including both secondary and tertiary flooding were conducted to observe the validity of IFT reduction and wettability alteration (contact angle decrease, CA) effects. IFT measurements showed that Dill and Hop surfactants can reduce the initial IFT of 28 mN/m to 2.443 and 5.614 mN/m, respectively. Ion concentration tuning showed that 10,000 ppm of NaCl is the optimum concentration that could enhance the optimization value of Dill surfactant from 91.27% to 92.8% (with 17.46% improvement compared with CMC of Dill). In addition, NaCl salt at the same concentration improved the effectiveness of Hop surfactant by 6.1%. Meanwhile, the used surfactants reduced the contact angle from 151° to 75° and 65° for Dill and HOP, respectively. Ion tuning showed that 10,000 ppm of salinity effect could enhance the optimization by Dill and Hop to 70.86 and 71.54%, respectively. Zeta potential measurements proved that the contact angle results in a complementary manner. Core flood tests validated previous results through the improvements in the recovery of oil by 8.56 and 10.11% original oil in place (OOIP) for HOP and Dill natural surfactants, respectively.