基于钻孔岩芯饼化现象的地应力估算方法探究及应用  

Exploration and application of in-situ stress estimation method based on core disking phenomenon of boreholes

作　　者：闫绍坤 王成虎 高桂云 刘冀昆 代向前 YAN Shaokun;WANG Chenghu;GAO Guiyun;LIU Jikun;DAI Xiangqian(National Institute of Natural Hazards,Ministry of Emergency Management,Beijing 100085,China;China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]应急管理部国家自然灾害防治研究院,北京100085 [2]中国地质大学(北京),北京100083

出　　处：《地质力学学报》2024年第6期865-877,共13页Journal of Geomechanics

基　　金：国家自然科学基金项目(42174118)。

摘　　要：岩芯饼化是在高地应力环境下产生的典型现象之一,其形成的岩饼的几何特征、断面形态与原地应力状态具有相关性,并且产生该现象的部位可能不适宜直接进行原地应力测量。为获得更全面、来源更广泛的地应力数据,依据该现象,基于饼化岩芯现场测量数据与原地应力之间的内在关系,进行地应力估算,所得结果对地应力测量数据具有补充完善的作用。依据岩芯饼化国内外研究相关假设和理论,分析岩芯饼化现象发生过程中出现的岩芯断面应力和岩芯内部能量变化情况,测量饼化岩芯的物理性质、几何特征,结合其原岩应力状态,构建基于岩芯饼化特征的地应力估算公式,并与其他公式作对比。对辽宁丹东大连山钻孔内出现岩芯饼化的30~120 m深度段73块代表性岩饼的几何特征进行测量,对该段岩芯物理性质进行试验,运用所构建的地应力估算公式估算该段地应力大小,补充完善水压致裂测量数据。同时依据国内外学者曾提出的基于岩芯饼化现象的其他地应力估算公式对该段进行估算,计算结果或偏离实际,或分布离散,相较之下以此公式估算补充后的地应力数据更符合实际,并满足产生岩芯饼化的应力条件。研究结果表明,该地应力估算方法所得结果可以补充完善钻孔饼状深度段地应力数据。[Objective]Rock core disking is a typical phenomenon that occurs in environments with high in-situ stress.The geometric characteristics and section shape of rock disking are related to the state of in-situ stress,and the site where this phenomenon occurs may be unsuitable for measuring in-situ stress.To obtain more comprehensive in-situ stress data from a wider range of sources,according to this phenomenon,in-situ stress estimation is conducted based on the internal relationship between the in-situ measurement data and the original in-situ stress,and the obtained result can supplement the in-situ stress measurement data.[Methods]According to the relevant hypotheses and theories worldwide,the change in core section stress and core internal energy during the core disking phenomenon was analyzed.The physical and geometric characteristics of the disked rock cores were measured,combined with the stress state of the original rock,and an in-situ stress estimation formula based on core disking characteristics was constructed.The results were compared with those of the other formulas.[Results]The geometric characteristics of 73 representative rock disks in the 30–120 m depth section of the Dalianshan borehole in Dandong,Liaoning Province,where the phenomenon of rock core disking occurs,are measured,and the physical properties of the core are tested.The value of the in-situ stress in this section is estimated using the established in-situ stress estimation formula to supplement and perfect the measured hydraulic fracturing data and better reveal the law of in-situ stress variation.[Conclusion]This section is estimated according to other in-situ stress estimation formulas based on the phenomenon of core disking proposed by scholars worldwide;the calculated results either deviate from reality or are dispersed in the distribution.Compared with these formulas,the in-situ stress data estimated by this formula are more in line with reality and meet the stress conditions for the generation of core disking.[Significance]The resu

关 键 词：岩芯饼化 高地应力 岩芯长短轴 地应力估算 

分 类 号：TD311[矿业工程—矿井建设] P553[天文地球—构造地质学]