裂缝封堵层结构形成与演化机制  

Structural formation and evolution mechanisms of fracture plugging zone

作　　者：许成元[1] 张敬逸 康毅力[1] 徐锋 林冲[1] 闫霄鹏 经浩然 商翔宇[4] XU Chengyuan;ZHANG Jingyi;KANG Yili;XU Feng;LIN Chong;YAN Xiaopeng;JING Haoran;SHANG Xiangyu(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation in Southwest Petroleum University,Chengdu 610500,China;CNPC International Exploration and Development Corporation,Beijing 100034,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,221116)

机构地区：[1]油气藏地质及开发工程国家重点实验室西南石油大学,成都610500 [2]中国石油国际勘探开发有限公司,北京100034 [3]中国石油勘探开发研究院,北京100086 [4]深部岩土力学与地下工程国家重点实验室中国矿业大学,江苏徐州221116

出　　处：《石油勘探与开发》2021年第1期202-210,共9页Petroleum Exploration and Development

基　　金：国家自然科学基金“基于逾渗和固液两相流理论的裂缝性储集层工作液漏失损害预测与控制”(51604236);油气藏地质及开发工程国家重点实验室开放基金“深层裂缝漏失性储集层封堵层细观力链表征及结构失稳机理研究”(PLN201913);四川省科技计划项目“保护储集层并改善优势天然裂缝导流能力的钻井预撑裂缝堵漏基础研究”(2018JY0436);非常规油气层保护四川省青年科技创新研究团队项目(2016TD0016)。

摘　　要：采用耦合计算流体力学-离散元(CFD-DEM)方法模拟了裂缝封堵层结构形成过程,采用自主研制的表征封堵层细观力链网络的光弹实验系统模拟了裂缝封堵层结构承压演化过程,揭示了裂缝封堵层结构形成与演化机制,形成了堵漏材料优选与堵漏配方设计新方法,为提高裂缝性储集层漏失控制效果提供理论依据。CFD-DEM模拟结果表明,架桥概率是决定封堵层结构形成和裂缝封堵效率的关键因素。提出了临界架桥与绝对架桥加量指标,作为架桥材料加量设计的依据。随着绝对架桥加量的增加,架桥模式由材料粒径主导向粒径-摩擦力共同主导转变。光弹实验结果表明,细观力链网络是裂缝封堵层结构承压演化的内在机制并决定宏观封堵层强度,堵漏材料性能参数影响力链网络结构和强力链占比,进而影响封堵层承压稳定性。根据研究结果优选了新型高封堵强滞留堵漏材料、优化了堵漏配方,室内裂缝封堵实验结果表明可有效提高裂缝封堵效率与封堵强度。A coupled CFD-DEM method is used to simulate the formation process of fracture plugging zone.A photo-elastic system characterizing mesoscale force chain network developed by our own is used to model the pressure evolution in fracture plugging zone to reveal the formation and evolution mechanisms of the structure of fracture plugging zone.A theoretical basis is provided for improving the lost circulation control effect in fractured reservoirs and novel methods are proposed for selecting loss control materials and designing loss control formula.CFD-DEM simulation results show that bridging probability is the key factor determining the formation of fracture plugging zone and fracture plugging efficiency.Critical and absolute bridging concentrations are proposed as the key indexes for loss control formula design.With the increase of absolute bridging concentration,the governing factor of bridging is changed from material grain size to the combination of material grain size and friction force.Results of photo-elastic experiments show that mesoscale force chain network is the intrinsic factor affecting the evolution of pressure exerting on the fracture plugging zone and determines the macroscopic strength of fracture plugging zone.Performance parameters of loss control material affect the force chain network structure and the ratio of stronger force chain,and further impact the stability and strength of fracture plugging zone.Based on the study results,the loss control formula is optimized and new-type loss control material is designed.Laboratory experiments results show that the fracture plugging efficiency and strength is effectively improved.

关 键 词：井漏 储集层保护 裂缝封堵层 封堵层结构 封堵强度 封堵效率 CFD-DEM模拟 光弹实验 堵漏材料 

分 类 号：TE28[石油与天然气工程—油气井工程]