页岩人工裂缝应力敏感评价方法EVALUATING METHOD OF THE STRESS SENSITIVITY FOR THE ARTIFICIAL FRACURES IN THE SHALE
李武广,钟兵,张小涛,胡志明,谢雳雳
LI Wuguang,ZHONG Bing,ZHANG Xiaotao,HU Zhiming,XIE Lili
摘要(Abstract)：
页岩储层具有低渗致密、无压裂不产气的特点,需要大型压裂改造产生易于气体流动的人工裂缝。为了定量化研究页岩人工裂缝应力敏感性,通过室内相似物理模拟实验,分析了人工裂缝宽度、渗透率、孔隙度随有效应力的变化规律。研究表明:无支撑人工裂缝初始渗透率相差不大,应力敏感变化规律一致,岩心渗透率提高幅度随应力的增加迅速下降,页岩造缝岩心应力敏感性极强;裂缝加入支撑剂后,初始渗透率相差较大,应力敏感性变弱,裂缝导流能力增加巨大;支撑剂破碎后有部分发生了弹性变形,对裂缝表面起到了较好的支撑作用。
Shale reservoir is characterized by low permeability,tight and no production without hydraulic fracturing,so it is necessary for the large-scale hydraulic fracturing to induce the artificial fractures where the shale gas can be mobile.In order to quantitatively study the stress sensitivity of the artificial fractures,by means of the indoor similar physical-property simulating experiment,the changed laws are analyzed for the fracture width,permeability and porosity with the effective stress.The research achievements show that for the fractures without the proppant,there are no obvious differences among the initial permeability,and moreover the changed laws of the stress sensitivity appear to be the same,with the rise of the stress,the enhanced degree of the core permeability decreases rapidly and furthermore the stress sensitivity is extremely strong for the shale fracture-induced core;when adding the proppant,the differential of the initial permeability becomes larger,the stress sensitivity turns weaker,the flowconductivity of the fracture increases significantly;after crushed for the proppant,the elastic deformation occurs for the partial proppants,thus much better supporting action is taken on the fracture surface.
关键词(KeyWords)：
页岩气;人工裂缝;应力敏感性;室内实验;水平井
shale gas;artificial fracture;stress sensitivity;indoor experiment;horizontal well
基金项目(Foundation): 国家重大专项“长宁—威远页岩气开发示范工程”(2016ZX05062002);国家重大专项“南方海相页岩气开采试验”(2011ZX05018-006)
作者(Author):
李武广,钟兵,张小涛,胡志明,谢雳雳
LI Wuguang,ZHONG Bing,ZHANG Xiaotao,HU Zhiming,XIE Lili
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