Novel low salinity fluid systems for unconventional EOR – Chammi Miller

In shale wells oil production declines after the first few years due to ultralow permeability, natural fractures, matrix heterogeneity, and formation damage. To keep the sustainability of the production, we need to develop cutting edge EOR techniques beneficial to the future of the oil and gas industry.

Our interest is to engineer low salinity formulations using green chemicals. The chemistry knowledge we apply in this research is not just limited to chemicals but expanded to brine composition optimizations, phase behavior studies, and chemical interaction evaluation with minerals. The chemical formulations we develop can be utilized as a frac fluid or inject into adjacent wells as a water-curtain for containment. Also, during the huff-n-puff process, these formulations can be used to pressurize a gas where the formulation can stimulate the matrix adjacent to the fractures. Chemicals are selected based on reservoir matrix chemistry and oil chemistry. The chemicals can increase stimulated reservoir volume (SRV) by creating micro-fractures in carbonate-rich reservoirs. Also, these chemicals can change the wettability of the fracture face, oxidize kerogen molecules, and dissolve organics and clear the flow path. Besides, we are looking into the use of produced water to design these formulations. In our studies, we thoroughly evaluate the chemistry of the matrix, formation brine, and crude oil composition to customize the fluid systems. We evaluate phase behavior, interfacial tension, zeta potential, and contact angles. We conduct spontaneous imbibition experiments to evaluate oil production under low pressure and high-pressure condition using oil-saturated cores. 

Zeng, T., Miller, C., & Mohanty, K. (2019, July 31). Chemical Blend-CO2 Huff-n-Puff for Enhanced Oil Recovery in Shales. Unconventional Resources Technology Conference. doi:10.15530/urtec-2019-362

Mohanty, K. K., Tong, S., Miller, C., Zeng, T., Honarpour, M. M., Turek, E., & Peck, D. D. (2019, November 1). Improved Hydrocarbon Recovery Using Mixtures of Energizing Chemicals in Unconventional Reservoirs. Society of Petroleum Engineers. doi:10.2118/187240-PA

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