砂砾岩水力裂缝延伸路径模拟研究  

Research on micro-morphology characteristics of hydraulic fractures for conglomerate reservoir

作　　者：罗攀[1] 李勇明[1] 江有适[1] 李源[2] 

机构地区：[1]西南石油大学油气藏地质与开发工程国家重点实验室,四川成都610500 [2]西南石油大学应用技术学院,四川成都610500

出　　处：《油气地质与采收率》2013年第5期103-106,110,共5页Petroleum Geology and Recovery Efficiency

基　　金：四川省杰出青年学术技术带头人资助计划"页岩气体积压裂理论与其应用研究"(2012JQ0010);新世纪优秀人才支持计划"油气藏增产理论与技术"(NCET-11-1062);国家科技重大专项"缝洞型碳酸盐岩油藏高效酸压改造技术"(2011ZX05014-006)

摘　　要：通过研究砾石尺度下水力裂缝的不规则延伸和压力波动的原因,优化砂砾岩储层的压裂设计及施工参数。将砂砾岩简化为由砾石、基质和界面3部分组成的复合介质,各部分具有不同的断裂韧性,并由断裂韧性得到判断裂缝延伸与停止延伸的指标——临界能量释放率。通过断裂力学理论与坐标变换,得到裂缝前沿处沿不同角度延伸的虚拟裂缝的应力强度因子和与之对应的能量释放率,裂缝延伸的优先方向即为最大能量释放率对应的方向,沿不同方向延伸的临界破裂压力可由能量释放率得到。通过编程模拟研究了包含不同粒径、含量和断裂韧性砾石的砂砾岩裂缝延伸规律与压力波动特点。模拟结果显示,砾石粒径、含量以及不同部分间断裂韧性的差异是导致砂砾岩裂缝不规则延伸或分叉及诱发施工压力波动的重要因素。To conduct better hydraulic fracture design and execution in conglomerate formation, this paper focuses on irregular fracture and pressure fluctuation when the hydraulic fracturing was conducted. The conglomerate was simplified as compound medium which is consisted of three mechanically different parts depending on critical energy release rate, fracture expands or stops. Based on fracture mechanism and coordinate transform, the energy release rate of virtual fracture at the tip of hydraulic fracture is derived, and then the best way for expansion is assigned. The critical fracture pressure is deducted from energy release rate and critical energy release rate. The simulation on morphology characteristics with different size, content, intensity gravels agree accords well with experimental results. Results show that the size and content of gravel, intensity of each part are significant influencing factors for characteristics and pressure fluctuation.

关 键 词：砂砾岩 不规则裂缝 裂缝延伸 压力波动 能量释放率 

分 类 号：TE357.13[石油与天然气工程—油气田开发工程]