Evaluation Of EOR Potential in Shale Oil Reservoir, Focusing on Wettability, and In-Situ Fluid Composition

Abstract

Developing shale oil and gas resources is becoming essential due to the continuous depletion of conventional reservoirs. As the thrust towards shale oil resources increases, the petroleum industry, especially in countries striving to mitigate the challenges of such reservoirs. One of the essential techniques utilized to increase the production capability of such reservoirs is hydraulic fracturing. Besides, EOR gas injection assists the recovery of the process by increasing pressure and decreasing the oil's viscosity. This research evaluates EOR potential by focusing on wettability variations on recovery performance. In unconventional shale oil reservoir. The candidate reservoir is based on a simple layer cake model, simulated on a dual permeability approach with four fractured layers. The reservoir is first perforated, and then the reservoir is undergone through the EOR CO2 cyclic gas injection process. They huff and puff cycle has been done in the reservoir model for ten years. The research studies the effect of wettability on an unconventional reservoir. Three different wettability cases in 3 different permeability models, i.e., 0.00001 mD, 0.0001 mD, and 0.001 mD, are studied. The sensitivity result shows that the 0.001 mD model possesses the highest cumulative production accounts for 550,000 BBL, followed by 0.0001 mD and 0.00001 mD. Through sensitivity analysis and comparison, it has been concluded that wettability variations do affect the recovery performance in the reservoir model that is even below 0.01 mD permeability. Besides, the changes in the wettability in 3 different permeability distribution models significantly improve the production performance of the reservoir.