Investigation of thermal eor via cyclic steam injection in fractured shale formation

The movement of hydrocarbon in a shale formation is restricted due to the ultra-low permeability. The ultra-low permeability usually creates capillary entrapment due to high capillary pressure. Fracturing was introduced in shale formation which creates more cross-sectional area of flow for the oil to be produced from shale formation. Another approach to increase the flow of hydrocarbon is by decreasing the viscous force via the mean of viscosity reduction. The ability of Thermal Enhanced Oil Recovery (EOR) in recovering light oil from ultra-low permeability shale was not thoroughly studied. This case study studied the potential of injecting cyclic steam into a fractured shale formation in the variation of steam qualities and fracture configurations. The simulation study incorporated data obtained from Bakken and Eagle Ford Shale Formation to ensure a representable dynamic model. The simulation study had been conducted using in-house commercial software by constructing a dual permeability synthetic model due to stark contrast of matrix and fractures permeability. Manual numerical computation was incorporated in the model to assess the dependency of relative permeability oil in the event of change in reservoir temperature which was the case since the simulation covered Thermal EOR. Fracture half-length was determined as the most sensitive factor in contributing to increase in oil recovery among all the fracture properties. Significant recovery of additional 46 in oil production for the most optimum case had been observed after incorporating recovery mechanisms of thermal expansion, wettability alteration and interfacial tension (IFT) reduction in the simulation. The amount of recovery increased from 1000 MSTB to 1460 MSTB when fracture half-length of 400 ft. and steam quality of 0.4 was used. © 2023 The Authors.