Flow characteristics of fractured horizontal wells in pressure-sensitive multi-media gas reservoirs

In the context of high-pressure and abnormally high-pressure gas reservoirs, the production pressure drop in gas wells can easily induce a strong pressure-sensitive effect. To investigate the flow characteristics of fractured horizontal wells in pressure-sensitive multi-media gas reservoirs, a comprehensive flow model for multi-stage fractured horizontal wells in pressure-sensitive multi-media gas reservoirs was established. By utilizing point source functions, perturbation methods, Laplace transforms and Fourier integral transforms, the analytical solution for unstable pressure in Laplace space was derived. Subsequently, by employing the Duhamel principle and Stehfest numerical inversion, the bottomhole pressure in real space was obtained, and the log-log theoretical diagram for well testing was plotted. The research shows that stress sensitivity amplifies pressure drop responses during the late flow stages, manifested as an upturn at the end of the log-log well testing curve. As the channeling coefficient increases, the earlier the channeling segment occurs in the multi-media gas reservoir, the more the channeling concavity on the pressure derivative curve moves to the left. The more the artificial fractures, the smaller the angle, the larger the half-length, and the further the pressure derivative curve moves downward. The newly established flow model for pressure-sensitive multi-media gas reservoirs, when combined with actual pressure recovery data, successfully fits and interprets the reservoir parameters and flow characteristics, which versa validates the accuracy of the model.