基于CT扫描的煤岩钻孔注液氮致裂试验研究

发布时间：2018-02-04 21:50

本文关键词： 注液氮煤层孔隙度致裂煤层增透钻孔 CT扫描　出处：《煤炭科学技术》2017年04期 　论文类型：期刊论文

【摘要】：为解决煤层气排采效率低的问题,提高煤储层渗透率,采用CT扫描的精细观测手段,对煤样进行钻孔注液氮实验,并分析其致裂过程与增透效果。研究结果表明:在冷冲击收缩应力与孔隙压力的双重作用下,煤岩注液氮钻孔周围发生了破裂,其孔隙率增加量随与钻孔距离增大呈负指数衰减。煤岩钻孔注液氮致裂效果随着与钻孔距离增加而减弱;增透效果在邻近钻孔的位置增加,由于碎胀作用,在远离钻孔的位置反而降低。液氮冷冲击对煤岩孔隙结构的影响与原始孔隙率之间具有一定相关性:即在原始孔隙率较低的区域,孔隙率增加较为明显,而在原始孔隙率较高的区域,孔隙率增加不明显甚至略有降低。研究结果证明注氮可以实现煤储层增透、提高煤层气排采产量。
[Abstract]:In order to solve the problem of low recovery efficiency of coal bed methane and improve the permeability of coal reservoir, the liquid nitrogen injection experiment of coal sample was carried out by means of fine observation of CT scanning. The results show that under the dual action of cold impact shrinkage stress and pore pressure, the fracture occurs around the drilling hole of liquid nitrogen injection. The increase of porosity decreases exponentially with the increase of the distance between the borehole and the borehole, and the effect of liquid nitrogen injection on the fracture of coal and rock borehole decreases with the increase of the distance between the borehole and the borehole. The antireflection effect increases in the location of adjacent boreholes due to dilatation. The effect of liquid nitrogen cold impact on the pore structure of coal and rock has a certain correlation with the original porosity, that is, in the region with low original porosity, the porosity increases more obviously. The results show that nitrogen injection can improve the permeability of coal reservoir and increase the production rate of coal bed methane.
【作者单位】：太原理工大学矿业工程学院;太原理工大学原位改性采矿教育部重点实验室;
【基金】：国家自然科学基金资助项目(21373146,51304142) 山西省高等学校创新人才支持计划资助项目(2014)
【分类号】：TD712.6
【正文快照】： 引用格式:王乔,赵东,冯增朝,等.基于CT扫描的煤岩钻孔注液氮致裂试验研究[J].煤炭科学技术,2017,45(4):149-154.Wang Qiao,Zhao Dong,Feng Zengchao,et al.Experimental study on fracturing of coal by injection liquid nitrogen in drill based on CT scanning[J].Coal Sci

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