Numerical Simulation of Stress Distribution Around a Well due to Fluid Flow in Poroelastic Tight oil and Gas Formation: An Application of Finite Element Method

摘要

Fluid injected around a wellbore in an oil and gas formation will affect the stress distribution which may change the stress state. This makes the hydraulic fracture more complex to propagate. Stress distribution around a wellbore is investigated in different fluid flowing conditions. The partial coupling strategy is applied to get effective stress from the stress model and fluid flow model. Finite Element Method is used to calculate the total stress distribution and the effective stress with fluid pressure. A numerical model is developed and verified by a commercial software and analytical solution. The developed numerical model is applied to generate the effective stress distribution. Numerical experiments are conducted to find out the factors to the effective stress. The results from current model suggest that it can effectively capture the total stress distribution and effective stress distribution around the wellbore. Model also suggests that fluid pressure has a significant effect on the stress distribution. The results from numerical experiments show that effective stress increases with wellbore radius and rock compressibility, but decreases with the fluid injection rate and rock compressibility. The results of this study can be used to improve the simulation of stress distribution near a wellbore for hydraulic fracturing design.