Pressure performance of multi-stage fractured horizontal well with stimulated reservoir volume and irregular fractures distribution in shale gas reservoirs

摘要

With the development of hydraulic fracturing technology of horizontal well, most unconventional gas reservoirs are developed by horizontal well multi-stage fracturing technology to improve gas well production. In this paper, we present a semi-analytical model of multi-stage fractured horizontal well (MFHWs) with consideration of adsorbed gas desorption and the irregular hydraulic fractures distribution in shale gas with the stimulated reservoir volume (SRV). On the bases of the point source function, Langmuir isotherm adsorption and Fick's law, wellbore pseudo-pressure solution of finite-conductivity MFHWs model is obtained by employing Laplace transform, finite cosine Fourier transform. and the discrete fracture approach in shale gas. The pressure transient responses log-log curves of MFHWs are drawn by Gauss elimination method and Stehfest numerical algorithm. In the light of the characteristics of the pressure derivative curve, the characteristics of each flow stage are identified and analyzed in detail. With the comparison of the commercial well test software numerical solution and the previous literature, the comparison results reach a good agreement under condition of same parameter. The effects of vital parameters, such as hydraulic fractures number and size of the SRV region, hydraulic fractures distribution styles and crossflow coefficient, on pressure transient curve are analyzed in detail. The presented model in this paper not only provides some insights for pressure dynamic analysis of shale gas reservoir development, but can help to engineers understand the pressure dynamics in shale gas reservoirs with SRV and irregular fracture distribution.