页岩储层黏土矿物对裂缝导流能力伤害的影响  

Effect of Clay Minerals in Shale Reservoirs on Fracture Conductivity

作　　者：杨柳[1,2] 石富坤[1] 赵逸清 葛洪魁 周彤[4] YANG Liu;SHI Fu-kun;ZHAO Yi-qing;GE Hong-kui;ZHOU Tong(State Key Laboratory of Geomechanics and Deep Underground Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;China University of Petroleum(Beijing)Unconventional Natural Gas Research Institute,Beijing 102249,China;Development Institute of Exploration and Development Research Institute,Xinjiang Oilfield Company,Karamay 834099,China;Research Institute of Petroleum Exploration and Development,China Petroleum&Chemical Corporation,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)深部岩土力学与地下工程国家重点实验室,北京100083 [2]中国石油大学(北京)非常规天然气研究院,北京102249 [3]新疆油田公司勘探开发研究院开发所,克拉玛依834099 [4]中国石油化工股份有限公司石油勘探开发研究院,北京100083

出　　处：《科学技术与工程》2020年第1期153-158,共6页Science Technology and Engineering

基　　金：国家自然科学基金青年基金(11702296)

摘　　要：页岩气的有效开发依赖于人工裂缝的产生,而要持续高效的进行页岩气开发,需要采用支撑剂保持人工裂缝的导流效果。目前,对于页岩储层支撑裂缝导流能力伤害的微观机理尚不清楚。以中国南方海相页岩为研究对象,开展岩板导流能力伤害实验,并与致密砂岩和常规砂岩进行对比,分析压裂液注入过程中导流能力变化规律。结果显示随着压裂液的持续注入,大量的支撑剂逐渐嵌入裂缝内,引起导流能力下降。初期导流能力下降较快,后期降速逐渐减缓。海相页岩支撑裂缝的导流能力伤害程度大幅度高于常规储层。常规储层支撑裂缝导流能力伤害率约为18%;而海相页岩的支撑裂缝导流能力伤害率为47%~85%。导流能力伤害率与黏土矿物含量和类型关系密切。随着黏土矿物含量的提高,导流能力伤害率迅速升高,尤其是伊利石和伊蒙混层存在可以明显提高导流能力伤害率。黏土矿物具有极强的吸水膨胀能力,易引起支撑裂缝表面硬度软化、蠕变强化,导致支撑剂嵌入和导流能力下降。研究结果为优化压裂液配方、改进页岩气井排采制度和提高页岩气的产出提供了解决方案。The effective development of shale gas depends on generation of artificial cracks,and continuous and efficient development of shale gas requires proppant to maintain the effect of artificial cracks.At the same time,to ensure the efficient development of shale gas,the conductivity of artificial fracture network must be maintained.At present,the microscopic mechanism of damage to the fracture conductivity of shale reservoirs is still unclear.Marine shale in southern China was taken as the research object,from which an experiment on diversion ability damage of rock plate was conducted,the experimental result was compared with those of tight sandstone and conventional sandstone,and the variation law of the conductivity of fracturing fluid during the injection process was analyzed.The results show that with continuous injection of fracturing fluid,a large amount of proppant was gradually embedded in the crack,causing the conductivity to decrease.The initial diversion capacity decreased rapidly,and the subsequent deceleration gradually slowed down.The degree of damage of the conductivity of the marine shale support crack was much higher than that of the conventional reservoir.The damage rate of conventional reservoir support fracture conductivity was about 18%,while the damage rate of support fracture conductivity of marine shale was between 47%~85%.The rate of damage to the conductivity was closely related to the content and type of clay minerals.With the increase of clay mineral content,the damage rate of the conductivity was rapidly increased,especially the presence of illite and illite-montmorillonite layers could significantly improve the damage rate of the conductivity.Therefore,clay minerals have a strong ability to absorb water and swell,which tends to cause softening and creep strengthening of the surface of the supporting cracks,resulting in a decrease in proppant embedding and conductivity.Results shall provide a solution to optimize the fracturing fluid formulation and improve the shale gas well drainage sy

关 键 词：页岩 导流能力 黏土矿物 压裂液 

分 类 号：TE348[石油与天然气工程—油气田开发工程]