Blasingame decline analysis for multi-fractured horizontal well in tight gas reservoir with irregularly distributed and stress-sensitive fractures

Abstract Multi-fractured horizontal well (MFHW) is commonly used in tight gas reservoirs to achieve commercial development, and the created hydraulic fractures are irregularly distributed and stress-sensitive in general. The Blasingame decline analysis method that can deal with the variable rate/BHP cases has attracted great interest. In this paper, a Blasingame decline analysis model of MFHW with irregularly distributed and stress-sensitive fractures in tight gas reservoirs is established. A novel method is adopted to solve the gas flow in stress-sensitive fractures. The Laplace transform, Stehfest numerical inversion, and an iteration method are employed to obtain the semi-analytical solution. Subsequently, the solution is validated with published solutions. Then, the effects of several key parameters (e.g., asymmetric fractures, fracture angle, stress-sensitive coefficient, the elastic storativity ratio) on the Blasingame decline curve are investigated. The results reveal that the stress-sensitive fracture conductivity is spatially variable. The stress-sensitive conductivity elevates with increasing distance to the wellbore. A negative influence of stress-sensitivity is found on the transient production rate. A larger γFD enhances the described negative influence. But when γFD is larger than 18, the reduction of production rate due to the increase of γFD becomes negligible. In addition, it is observed that the Blasingame decline type curve moves downward when fractures are asymmetric. When considering fracture asymmetry, a more significant pressure loss from the wellbore to the fracture tip is found in the fractures with a longer length. The proposed model provides some insights with regard to production optimization and reservoir parameter interpretation.