页岩压裂水平井增产改造体积的动态演化模型
摘要
For shale gas reservoir, hydraulic fracturing in horizontal well is the key technology to guarantee its commercial exploitation, and the stimulated reservoir volume (SRV) is a critical parameter deciding the post-fracturing performance. The SRV estimation plays an important role in shale gas fracturing design as well as post-fracturing evaluation, so it has become a hot topic in shale fracturing research. Based on the limitations of existing SRV estimation methods, a dynamic evolution model was built to simulate the forming process of the SRV, which coupled several vital processes during shale fracturing, including the formation stress changing, the reservoir pressure rising and the natural fracture failure mechanism. The real physical process of the SRV formation was fully considered in this model, e.g., the non-planar propagation of multiple hydraulic fractures and the SRV extending with the reservoir permeability, etc., so the model can yield more reliable results for field application. The model was firstly validated with calculated results compared with on-site micro-seismic monitored data for a fractured horizontal well in the Weiyuan shale gas field in southwest China, then it was applied to analyze the forming process and extending behavior of the SRV. The research can not only improve the SRV estimation reliability of multi-stage and multi-cluster fracturing in horizontal shale gas wells, but also provide theoretical guidelines and potential applications for fracturing design and post-fracturing evaluation.