页岩层理对压裂裂缝垂向扩展机制研究

发布时间：2018-09-08 10:32

【摘要】：文章采用页岩露头开展了大型三维压裂裂缝物理模拟研究,考察了围压、排量、压裂液黏度等参数对水力裂缝垂向扩展的影响,综合分析了水力裂缝尖端应力场和远场应力作用在层理面上的应力场,建立了判断水力裂缝是否穿透层理面的穿透准则。研究表明,不同于常规砂岩储层,层状页岩压后裂缝形态复杂,水力裂缝极易沟通层理形成纺锤状裂缝网络;地应力状态是影响水力裂缝是否穿透层理的最关键因素,水平地应力差值存在一个临界值,小于该临界值不能穿透层理面;提高压裂液黏度及排量能够增加水力裂缝穿透层理面的几率,黏度过高会降低裂缝沟通体积。基于文章研究结果,取得了规律性认识,为水平井眼轨迹的部署、压裂层段的选择、压裂优化设计和压裂现场质量控制等提供了重要依据。
[Abstract]:In this paper, shale outcrop is used to carry out a large-scale three-dimensional fracturing physical simulation study. The effects of confining pressure, displacement and viscosity of fracturing fluid on the vertical propagation of hydraulic fractures are investigated. The stress field at the tip of hydraulic fractures and the stress field at the far field acting on the bedding surface are analyzed comprehensively, and the judgment of whether hydraulic fractures penetrate the bedding surface is established. The results show that, unlike conventional sandstone reservoirs, the fracture morphology of layered shale after fracturing is complex, and the hydraulic fractures are easy to communicate with bedding to form a spindle fracture network; the stress state is the most critical factor affecting whether hydraulic fractures penetrate the bedding or not, and there is a critical value of the horizontal stress difference, which is less than this critical value can not penetrate the bedding. Increasing the viscosity and displacement of fracturing fluid can increase the probability of hydraulic fracture penetrating the bedding surface, and too high viscosity can reduce the volume of fracture communication. According to it.
【作者单位】：中国石油勘探开发研究院;中国石油大学油气资源与探测国家重点实验室·北京;
【基金】：国家科技重大专项“页岩气勘探开发关键技术”(2012ZX05018004)资助
【分类号】：TE357.11

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