Pressure transient analysis of multi-fractured horizontal wells in tight oil reservoirs with consideration of stress sensitivity

Abstract

Multi-fractured horizontal well (MFHW) is an effective technique to develop unconventional reservoirs. Complex fracture network around the well and hydraulic fractures is formed during the fracturing process. Fracture network and hydraulic fractures are the main seepage channel which is sensitivity to the effective stress. However, most of the existing models do not take the effect of stress sensitivity into account. In this study, a new analytical model was established for MFHW in tight oil reservoirs based on the trilinear flow model. Fractal porosity and permeability were employed to describe the heterogeneous distribution of the complex fracture network, and the stress sensitivity of fracture was considered in the model. The Pedrosa substitution and perturbation method were applied to eliminate the nonlinearity of the model. By using the Laplace transformation method, the analytical solutions in Laplace domain were obtained. Then, validations were performed to show that the model is valid. Finally, sensitivity analysis was discussed. The presented model provides a new approach to the estimation of fracturing effect and can be also utilized for recognizing formation properties of tight oil reservoirs.