A Semi-Analytical Pressure-Transient Model to Deted Inter-well Interference of Multi-Well-Pad-Production Scheme in Shale Gas Reservoirs

摘要

Recently, Multi-Well-Pad-Production (MWPP) scheme has been in the center of attention as a promising technology to improve Shale Gas (SG) recovery. However, Inter-Well Pressure Interference (IWPI) induced by MWPP scheme severely distorts flow regimes, which strongly challenges the traditional pressure-transient analysis methods, which focus on Single Multi-Fractured Horizontal Wells (SMFHW) without IWPI. Therefore, a methodology to identify pressure-transient response of MWPP scheme without and with IWPI is urgent. To fill this gap, by utilizing superposition theory, Gauss elimination and Stehfest numerical algorithm, the pressure-transient solution of MWPP scheme was established, as a result, type flow regimes can be identified by considering MWIP. Our results show that our proposed model demonstrates promising calculation speed and acceptable accuracy compared to numerical simulation. Part of flow regimes are significantly distorted by IWPI. In addition, well rate mainly determines the distortion of pressure curves, while fracture length, well spacing, fracture spacing mainly determine when the IWPI occurs. The smaller the gas rate, the more severely flow regimes are distorted. As the well spacing increases, fracture length decreases, fracture spacing decreases, occurrence of IWPI becomes later. Stress sensitivity coefficient approximately has no influences on distortion of pressure curves and occurrence of IWPI. This work gains some additional insights on pressure-transient response for MWPP scheme in SG reservoir, which can provide considerable guidance on fracture properties estimation as well as well pattern optimization for MWPP scheme.