页岩裂缝网络的几何特征二维表征及连通性分析  

2D Characterization of Geometric Features and Connectivity of Fracture Networks in Shale Formations

作　　者：李玮[1] 赵欢[1] 李思琪[1] 李立 孙文峰[1] 

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318 [2]濮阳佰斯泰油气技术服务有限公司,河南濮阳457001

出　　处：《石油钻探技术》2017年第6期70-76,共7页Petroleum Drilling Techniques

基　　金：国家自然科学基金重大项目"页岩油气高效开发基础理论研究"之课题"页岩非线性工程地质力学特征与预测理论"(编号:51490650)资助

摘　　要：节理、裂缝等弱结构面非常发育是页岩地层的基本结构特征,裂缝网络的有效沟通可以增大压裂改造体积,正确认识和描述裂缝网络形态及连通性对合理有效开发页岩油气藏具有十分重要的意义。为准确描述页岩天然裂缝网络几何特征二维表征及其连通性,以分形几何和拓扑几何为理论依据,建立了页岩裂缝组裂缝尺寸、裂缝数量的分形描述模型,给出了裂缝网络连通节点类型、分支数、裂缝平均连通点数和分支平均连通点数等的计算模型,并对裂缝网络连通性进行了二维模拟,分析了分形维数、裂缝组数和裂缝组交角对裂缝网络连通性的影响。研究发现:天然裂缝分布的数量与发育程度受分形维数、组数和初始数量控制,随分形维数增大而增大;在其他参数不变的条件下,裂缝平均连通性和分支平均连通性对分形维数、裂缝组数、裂缝组交角等参数敏感,随分形维数的增大呈现降低趋势,随裂缝组数增加而升高,随裂缝组交角增大而升高。该研究结果可为合理制定页岩储层开发方案提供理论支撑。Joints,fractures and other weak structural planes can be identified as the fundamental structural features of shale formations.Since effective communication among fractural networks can effectively enhance fractured reservoir volume,the understanding and description of configurations and connectivity of fracture network are of great importance for high-efficiency development of shale oil/gas reservoirs.To obtain accurate representations of the the geometric features,2 Dcharacterization and connectivity of natural fracture networks in shale,the fractural geometry and topologic geometry are used as a theoretical foundation to construct a fractural description model for fractural sizes and quantity in shale.In this way,calculation models for fracture node type,number of branches,average connectivity of fractures can be established.In addition,2 Dsimulations have been performed for fracture network connectivity to highlight impacts of fracture dimension,fracture groups and angles to connectivity of fracture network.Research results showed that the quantity and development of natural fractures are subject to fractural dimensions,groups and initial quantity.Generally speaking,natural fractures increase with an increase in fractal dimensions.With other parameters remain unchanged,the average connectivity of fractures and branches is sensitive to fractal dimensions,fracture groups,fracture angles and other parameters.The connectivity may decrease with the increase in fractal dimensions and may increase with the increase in groups and angles.Relevant research results may provide theoretical foundation programs making in shale reservoirs development.

关 键 词：页岩地层 天然裂缝 裂缝网络 网络连通性 分形几何 

分 类 号：TE348[石油与天然气工程—油气田开发工程]