摘要
我国页岩气储备多处于川、贵等地的高山丘陵或西北水资源匮乏地区,使用水力压裂法受到限制.液氮致裂作为页岩气开采技术,使用局限性小.但因为该技术成本高昂、使用经验少,所以施工中常难以充分发挥液氮的致裂效果.因此研究液氮致裂破坏规律,充分发挥液氮的冻胀致裂的效果,达到降低施工成本的目的十分必要.本文通过数值模拟的研究方法分别模拟了高径比范围为0.3-3.0的7种页岩模型经冷冲击处理后岩体破裂的过程.试验结果表明:页岩高径比值域为1.5-2.5时,试件会产生有效破坏岩体结构的横向贯穿裂缝以及纵向贯穿裂缝,在该高径比范围内试件的最终破坏效果相比其他高径比范围的页岩模型更为显著.通过控制液压或其他技术手段调整开采区域页岩裂缝,使裂缝间的页岩到达适宜高径比,再注入液氮能够让页岩被充分的冻胀破坏,就能够大幅度节约开采成本.
Shale gas reserves in China are mostly located in high mountains and hills of Sichuan,Guizhou and other places,or in the northwest of China with scare water resources,where shale gas production technology,liquid nitrogen fracturing are restricted.However,due to its high cost and less experience,it is often difficult to give full play to the cracking effect of liquid nitrogen in construction.Therefore,it is necessary to study the law of liquid nitrogen cracking,make full use of the effect of liquid nitrogen frost heave cracking,and reduce the construction cost.In this study,the fracture process of 7 shale models with a height diameter ratio of 0.3-3.0 was simulated by numerical simulation.The test results show that when the range of the ratio of height to diameter of shale is 1.5~2.5,the transverse and longitudinal cracks that can effectively destroy the rock mass structure will be produced,and the final failure effect of the specimen within the range of the ratio of height to diameter is more significant than that of other shale models.By controlling the hydraulic pressure or other technical means to adjust the shale fractures in mining areas,the shale between the fractures can reach the appropriate height diameter ratio,and then by injecting liquid nitrogen the shale can be fully damaged by frost heave,which contributes to the great reduction of the mining cost.
作者
王奎胜
包春燕
秦周傲宇
WANG Kuisheng;BAO Chunyan;QIN Zhouaoyu(School of Civil Engineering,Shaoxing University,Shaoxing,Zhejiang 312000;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing,Zhejiang 312000)
出处
《绍兴文理学院学报》
2020年第10期35-42,共8页
Journal of Shaoxing University
关键词
液氮开采
高径比
裂缝
数值模拟
liquid nitrogen mining
height diameter ratio
fracture
numerical simulation
