Evaluation of Eagle Ford Cyclic Gas Injection EOR: Field Results and Economics

Abstract Eagle Ford Cyclic Gas Injection EOR (CGEOR) was started in late 2012, by EOG Resources, and has expanded to over 30 leases by 6 operators (266 wells) to date where produced gas is being injected. An extensive EOR evaluation was initiated by Shale IOR to understand results for these leases. This paper will provide a summary of EOR production evaluation results, pilot history match, and economics for two Eagle Ford projects through June 2019. All production, injection volumes, and other data were obtained from the Texas Railroad Commission. These pilots and commercial projects represent a range of outcomes. We evaluate base decline EUR and incremental IOR oil production. Detailed compositional simulation is used to understand process PVT phase behavior and make accurate well and unit production profiles which guide our understanding of field results. We explain the process to predict project profiles and generate rigorous cash flows to understand economic drivers. Results of this study show that CGEOR throughout the Eagle Ford volatile oil can yield an additional 30% to 90% increase in EUR with robust economics, depending on compressor utilization and field life. The CGEOR process appears to be working without any failures thus far in the Eagle Ford, however, phase behavior must be understood along with operational efficiency in order to achieve good economics. Eagle Ford field results show that compressor and well operations are key to production efficiency as oil production closely follows gas injection volumes. These results should also be helpful to build upon knowledge in other unconventional basins.