页岩气藏体积压裂水平井产能模拟研究进展

Advances of Simulation Studies of Volumetric Fracturing Horizontal Well Productivity for Shale Gas Reservoir

页岩气储层孔喉细小,渗透率极低,一般无自然产能,需借助水平井和体积压裂技术才能实现经济开发。国内外关于页岩气的研究多集中于地质评估和开发工艺,而适用于页岩气体积压裂水平井产能的理论研究相对较少。页岩气产能研究的关键在于多尺度渗流机制的准确描述和复杂裂缝网络的精细表征。通过广泛调研和分析,探讨了页岩储层多尺度渗流机制;总结了页岩气藏多裂缝水平井试井模型,阐述了不同模型关于流态划分、储层和裂缝参数评估的应用;系统介绍了页岩气数值模拟方法,包括常规数值模拟方法、离散裂缝网络模型方法及有限元方法,认为后两者是未来页岩气产能数值模拟的发展趋势。

Shale gas reservoir is characterized by nanoscale porosity and ultra-low permeability,which usually has no natural productivity,and has to be economically developed by means of horizontal well and volumetric fracturing technology. The study on shale gas at home andabroad mostly focused on geological characteristic evaluation and development process technologies,with few theoretical approaches to itsproductivity by volumetric fracturing horizontal drilling process. The key to shale gas production research should be in exact description ofmultiple scale flow mechanism and fine characterization of complex hydraulic fracture networks. Through wide investigation and analyses,this paper discusses such a flow mechanism,reviews the model for multiple transverse fracture horizontal well test in shale gas reservoir,elaborates how to distinguish flow regimes and evaluate reservoir and fracture parameters according to different models,and systematicallyintroduces the methods of numerical simulation for shale gas,including conventional numerical modeling,discrete fracture network model-ing and finite element approaches. It is believed that the discrete fracture network modeling and finite element approaches will be the fu-ture research trend for numerical simulation of shale gas productivity.