四川页岩压裂裂缝扩展实验及力学特性研究

发布时间：2018-06-21 07:40

本文选题：页岩 + 裂缝扩展　；参考：《中国科学:物理学力学天文学》2017年11期

【摘要】：采用真三轴压裂物理模拟的方法,研究了四川页岩储层压裂过程中的水力裂缝扩展行为和裂缝形态.实验结果表明,四川页岩压裂裂缝扩展模式分为主裂缝多分支裂缝和网状复杂裂缝.在水平主应力差较高的实验条件下,压力曲线波动频率高且趋势平稳,实时声发射监测结果表明,在实验的前期压裂裂缝易穿过天然节理,并形成单一主裂缝,而在实验的后期易形成多分支裂缝;在水平应力差较低条件下,压力曲线波动频率高但是不时伴有压力陡降,声发射监测结果表明,水力裂缝扩展易沿着页岩天然裂缝系统扩展,并形成复杂裂缝形态.定义了水力裂缝垂直穿过页岩层理面时的临界摩擦系数,采用实验参数和结果,揭示了在上述条件下,水平地应力差异系数和临界摩擦系数之间的相互关系,随着水平地应力差异系数的增加,临界摩擦系数显著降低.上述研究对中国的深层页岩气开发具有一定的指导意义.
[Abstract]:The hydraulic fracture propagation behavior and fracture morphology of Sichuan shale reservoir during fracturing were studied by using true triaxial fracturing physical simulation method. The experimental results show that the fracture propagation mode of Sichuan shale fracturing can be divided into main fracture multi-branch fracture and reticular complex fracture. Under the experimental conditions of high horizontal principal stress difference, the fluctuation frequency of pressure curve is high and the trend is stable. The real time acoustic emission monitoring results show that the fracture is easy to pass through natural joints and form a single main fracture in the early stage of the experiment. In the later stage of the experiment, multiple branching fractures are easily formed, and under the condition of low horizontal stress difference, the pressure curve fluctuates frequently but is accompanied by steep pressure drop from time to time. The results of acoustic emission monitoring show that, Hydraulic fracture propagation is easy to extend along shale natural fracture system and form complex fracture form. The critical friction coefficient of hydraulic fractures perpendicular to shale bedding surface is defined. The relationship between horizontal stress difference coefficient and critical friction coefficient is revealed by using experimental parameters and results. With the increase of the coefficient of horizontal stress difference, the critical friction coefficient decreases significantly. The above research has certain guiding significance for deep shale gas development in China.
【作者单位】：中国石化石油工程技术研究院;页岩油气富集机理与有效开发国家重点实验室;
【基金】：国家自然科学基金(编号:51490653) 中国石化科技部课题(编号:P15173)资助项目
【分类号】：TE377

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