Prediction of oil recovery in naturally fractured reservoirs subjected to reinfiltration during gravity drainage using a new scaling equation

Abstract

By comparing numerical simulation results of single-porosity and dual-porosity models, the significant effect of reinfiltration to naturally fractured reservoirs was confirmed. A new governing equation was proposed for oil drainage in a matrix block under the reinfiltration process. Utilizing inspectional analysis, a dimensionless equation suitable for scaling of recovery curves for matrix blocks under reinfiltration has been obtained. By the design of experiments, test cases with different rock and fluid properties were defined to confirm the scope of the presented equation. The defined cases were simulated using a realistic numerical simulation approach. This method can estimate the oil amount getting into the matrix block through reinfiltration, help simulate the oil drainage process in naturally fractured reservoirs accurately, and predict the recovery rate of matrix block in the early to middle periods of production. Using the defined scaling equation in the dual-porosity model can improve the accuracy of the predicted recovery rate.

Keywords

• naturally fractured reservoir
• gravity drainage
• reinfiltration
• scaling equation
• dual-porosity simulation
• inspectional analysis