Study on production decline of complex fracture network in tight oil reservoirs based on embedded discrete fracture model

Abstract The Blasingame production decline analysis method is crucial for analyzing the production dynamics of fractured horizontal wells in tight reservoirs. In actual tight reservoirs, the fluid flow within the reservoir is often non-Darcy flow due to the threshold pressure gradient (TPG) and stress sensitivity. In this paper, we establish a mathematical model of fluid flow in tight reservoirs based on the embedded discrete fracture model (EDFM) and solve the model using the finite volume method. The threshold pressure gradient and stress sensitivity of matrix are taken into account in this model. Typical curves of Blasingame production decline are obtained by normalized pressure algorithm. The curves are divided into four flow stages. The effects of different stress sensitivity, threshold pressure gradient, major fracture half-length, number of secondary fractures in the stimulated reservoir volume, and the distribution pattern of secondary fractures on the production decline are analyzed respectively. With the increase of stress sensitivity coefficient and threshold pressure gradient, the pressure drop rate increases and the Blasingame curve moves downward. The half-length of major fractures has less effect on the curve. The number of secondary fractures increases and all stages of the curve move upward. The Blasingame curve is at the top when the secondary fractures are vertical to the major fractures. When the secondary fractures are parallel to the major fractures, the curve is at the bottom. This study will provide scientific basis for analyzing production dynamics in tight reservoirs.