新井定向射孔转向压裂裂缝起裂与延伸机理研究  

Study on initiation and propagation mechanism of fractures in oriented perforation of new wells

作　　者：张广清[1] 陈勉[1] 赵艳波[2] 

机构地区：[1]中国石油大学石油天然气工程学院 [2]大庆油田有限责任公司第九采油厂,黑龙江大庆163853

出　　处：《石油学报》2008年第1期116-119,共4页Acta Petrolei Sinica

基　　金：国家自然科学基金项目(No.90510005)“深层应力敏感性复杂地层的钻井液漏失规律研究”;国家自然科学基金项目(No.50274054)“水平井水力裂缝非平面扩展的物理模拟研究”联合资助

摘　　要：为了提高特低渗油藏新井的压裂效果,提出了采用定向射孔技术进行转向压裂从而形成双S型水力裂缝的新方法。基于有限元三维应力分析,研究了定向射孔下水力裂缝的起裂机理。考虑任意裂缝形态、地应力和缝内液体压力分布的影响,建立了任意形状裂缝应力强度因子的确定模型;同时考虑I型和II型断裂,建立了复合裂缝延伸准则。提出了定向射孔水力压裂裂缝的延伸轨迹计算模型和步骤,编制了裂缝延伸的模拟软件。采用地面微震进行了3口井的现场验证,地面微震检测结果与计算结果吻合。利用定向射孔压裂技术在单个层内可以形成双S型水力裂缝,可作为提高特低渗透油田产量的一种方式。In order to improve fractures in new wells of low-permeability reservoirs, a new methodology to generate dual-S fractures in deflection fracturing of oriented perforation was proposed. The three-dimensional finite element method was used to study the mechanism of fracture initiation in oriented perforation. Considering the shape of arbitrary fracture, underground stress and fluid pressure distributed in fractures, a model for specifying stress intensity factor of arbitrary fracture was set up. The propagation criteria for mixed-type fracture of type Ⅰ and type Ⅱ were also presented. The models and computation procedures for determining fracture propagation path were provided, and the software for simulation of fracture propagation was developed. Surface micro-seismic technique was used in fracturing treatment of three wells to monitor fracture propagation directions. The monitoring results agreed well with the model prediction. The dual-S type fractures can be generated in a single formation by using oriented perforation fracturing technology, which may be an effective method to improve oil production in ultra-low permeability reservoir.

关 键 词：特低渗透油藏 水力压裂 定向射孔 转向压裂 双S型裂缝 计算模型 

分 类 号：TE21[石油与天然气工程—油气井工程]