二氧化碳爆破致裂激发干热岩储层作用效果  

Effect of stimulation in hot dry rock reservoirs from carbon dioxide blasting-induced cracking

作　　者：窦斌[1] 肖鹏 郑君 田红[1] 崔国栋 吴天予 Dou Bin;Xiao Peng;Zheng Jun;Tian Hong;Cui Guodong;Wu Tianyu(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074)

机构地区：[1]中国地质大学(武汉)工程学院,武汉430074

出　　处：《地质科技通报》2022年第5期150-159,共10页Bulletin of Geological Science and Technology

基　　金：国家重点研发计划(2019YFB1504201);自然资源部深部地热资源重点实验室开放基金(KLDGR2022K01)。

摘　　要：采用二氧化碳爆破致裂为激发干热岩储层提供了一种新的技术思路和途径。为了探究二氧化碳爆破致裂激发干热岩储层的作用效果,开展了二氧化碳爆破致裂干热岩储层作用范围的数值模拟研究。考虑实际开采过程中钻井液对井壁附近干热岩储层的降温影响,采用以温差为变量的拟合函数设置损伤区储层材料参数,用洗井后井壁附近储层温度分布函数设置损伤区储层温度场,并借助炸药爆破的相关理论、公式设置爆破荷载,结合COMSOL软件模拟了二氧化碳爆破致裂激发干热岩储层的过程。结果表明,二氧化碳爆破致裂干热岩过程中存在多次应力集中作用,且在炮孔附近压应力集中造成压碎区,压碎区外拉应力作用形成裂隙区;储层的初始温度以及定压片厚度都会影响二氧化碳爆破致裂激发干热岩储层的作用效果,其中初始温度对爆破压碎区范围影响较大,对裂隙区范围影响较小,定压片厚度改变对压碎区范围影响较小,主要影响爆破裂隙区的分布。本研究成果可为干热岩地热能后续的开采利用提供理论支持和参考。Carbon dioxide blasting provides a new technical idea and way to stimulate hot dry rock reservoirs.To explore the effect of carbon dioxide blasting-induced cracking on dry-hot rock reservoirs,a numerical simulation for the action range of carbon dioxide blasting-induced cracking of hot dry rock was carried out.Considering the cooling effect of drilling fluid on the hot dry rock reservoir near the wellbore in the actual mining process,the fitting functions with temperature difference as a variable were adopted to set the material parameters of the reservoir in the damaged area,and the temperature distribution functions of the reservoir near the wellbore after well washing were adopted to set the temperature field of the reservoir in the damaged area.The blasting load was set by the relevant theories and formulas of explosive blasting.Combined with COMSOL software,the process of carbon dioxide blasting to stimulate hot dry rock reservoirs was simulated.The results showed that there were multiple stress concentrations in the process of the dry hot rock cracking caused by carbon dioxide blasting,the compressive stress concentration near the blast hole produced the crushing zone,and the tensile stress outside the crushing zone formed the fracture zone.In addition,the initial temperature of the reservoir and the thickness of the pressure plate would affect the effect of carbon dioxide blasting fracturing to stimulate dry and hot rock reservoirs.The initial temperature had a great influence on the scope of the blasting crushing zone and had little influence on the scope of the fracture zone.The thickness of the pressure plate had little influence on the scope of the crushing zone,which mainly affected the distribution of the blasting fracture zone.The research results could provide a theoretical support and a reference for the subsequent exploitation and utilization of dry-hot rock geothermal energy.

关 键 词：干热岩 储层激发 二氧化碳爆破 地热能 数值模拟 

分 类 号：P314[天文地球—固体地球物理学]