摘要
常规水压致裂方法在倾斜钻孔应力测量尤其是三维应力测量中受到极大的限制,而原生裂隙水压致裂地应力测量方法需要大量原生裂隙才能得到合理的结果。结合倾斜钻孔中完整岩体段常规水压致裂与原生裂隙重张试验,通过优化原生裂隙面剪应力假定并结合常规水压致裂法给出的钻孔截面应力,建立观测值方程组,利用蒙特卡罗算法,实现了倾斜钻孔中三维应力张量反演,并通过天津蓟州某抽水蓄能电站倾斜钻孔的三维应力测量,验证本文方法的可靠性和准确性。研究结果表明,本文所提方法只需选择1段或以上完整岩体段常规压裂试验和1段或以上原生裂隙段重张试验,就可以得到倾斜钻孔三维应力状态。与仅采用原生裂隙水压致裂法相比,本文方法大大降低了对原生裂隙数目要求,反演得到的数据离散性小,稳定性高,且结果与区域应力状态较为一致,为单孔斜孔(或垂直孔)中三维地应力张量的获取提供新的思路与可靠途径。
The conventional hydraulic fracturing(HF)method is greatly limited in the in situ stress measurements of inclined boreholes,especially in three-dimensional stress measurements.Moreover,the hydraulic tests on preexisting fractures(HTPF)requires a large number of pre-existing fractures to obtain reasonable results.By optimizing the assumption of shear stresses on the primary fracture surfaces and using Monte Carlo algorithm,the threedimensional stress tensor inversion in the inclined borehole was realized by combining the conventional HF and the HTPF tests.The reliability and accuracy of the proposed method were verified by three-dimensional stress measurements of an inclined borehole in a pumped storage power station in Jizhou,Tianjin.The results show that the proposed method can determine the three-dimensional stress tensors of the inclined borehole only by selecting 1 or more test intervals for conventional HF tests in intact rock mass and 1 or more test intervals for HTPF tests.Compared with the HTPF method that only adopts pre-existing fractures in stress determination,the proposed method greatly reduces the requirement of the number of pre-existing fractures.The inversion results have little dispersion and high stability,which are also consistent with the regional stress state.The proposed method provides a new idea and a reliable approach to determine the stress tensor using a single inclined or vertical borehole.
作者
高桂云
王成虎
刘冀昆
武凝雨
闫绍坤
林淇七
GAO Guiyun;WANG Chenghu;LIU Jikun;WU Ningyu;YAN Shaokun;LIN Qiqi(National Institute of Natural Hazards,Ministry of Emergency Management of China,Beijing 100085,China;School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083,China;College of Geological Engineering,Institute of Disaster Prevention,Sanhe,Hebei 065201,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2024年第S02期3700-3709,共10页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(42174118)
关键词
岩石力学
倾斜钻孔
三维应力张量
水压致裂
原生裂隙
蒙特卡罗方法
rock mechanics
inclined borehole
three-dimensional stress tensor
hydraulic fracturing
pre-existing fractures
Monte Carlo algorithm
作者简介
高桂云(1984-),女,2014年毕业于北京大学固体力学专业,现任副研究员,主要从事岩石力学、地应力与地质力学等方面的研究工作。E-mail:guiyungao@ninhm.ac.cn;通讯作者:王成虎(1978-),男,博士,现任研究员。E-mail:huchengwang@163.com
