地质力学学报2025，Vol.31Issue(6)：1146-1158,13.DOI:10.12090/j.issn.1006-6616.2025153
"一孔之见"——钻孔中的应力观测如何表征地壳应力状态?
How do borehole observations characterize crustal stress?
摘要
Abstract
[Objective]Knowing the in-situ stress state is of great importance for understanding a wide range of geomechanical processes in the Earth's crust,and for addressing many practical problems in the subsurface.The in-situ stress characterization in boreholes through the classic hydraulic fracturing test and borehole failure observation has provided fundamental knowledge of the stress state in the brittle upper crust.[Methods]Compiling borehole observations and other stress indicators over much larger scales reveals coherent and consistent stress orientations and relative stress magnitudes over appreciable depths and between boreholes at the regional scale.Stress magnitudes determined using the hydraulic fracturing method and borehole failure observation are consistent with the classic Anderson and Coulomb faulting theories,as well as with the empirical Byerlee's law.This is useful for constraining the in-situ stress state and quantifying fault stability.The general state of frictional equilibrium in the upper crust is present,although stress variations at local scales due to discontinuities,lithology contrasts,rock mass anisotropy and other factors are practically ubiquitous.[Results]To date,the hydraulic fracturing method and borehole failure observations—and their evolved variants—remain extremely useful.However,given the challenges ahead in subsurface exploration and engineering,it is imperative that we fundamentally revolutionize how we collect,interpret,and share the stress data with innovative developments in crustal stress characterization.[Significance]In this paper,we also present several ongoing projects that attempt to innovate stress observations at various scales.These attempts build upon the foundation laid by hydraulic fracturing tests and borehole failure observations.At the scale of individual boreholes,deep learning is being employed to automatically identify borehole stress indicators,such as fractures and breakouts,in image logs to increase the efficiency and robustness of stress interpretation.Processed image logs with various characteristics can further improve the applicability of deep learning models.At the scale of borehole arrays in subsurface engineering,the use of multiple boreholes and complementary approaches(hydraulic fracturing tests and borehole failure observations)enables stress characterization at finer spatial scales,which prompts the understanding of stress distribution and engineering practicality.At the scale of ultra-deep boreholes,the identification and classification of uncommon stress indicators,such as natural fractures,are utilized to invert the in-situ stress and crustal rock mass strength.The inversion confirms the frictional equilibrium hypothesis and offers an alternative approach for stress characterization.[Conclusion]These attempts underscore the importance of moving beyond the paradigm of borehole stress characterization and the interconnectedness between classic theories and novel developments.关键词
地应力/水压致裂/钻孔破坏/天然裂缝/摩擦平衡Key words
in-situ stress/hydraulic fracturing/borehole failures/natural fractures/frictional equilibrium分类
天文与地球科学引用本文复制引用
MA Xiaodong.."一孔之见"——钻孔中的应力观测如何表征地壳应力状态?[J].地质力学学报,2025,31(6):1146-1158,13.基金项目
深地国家科技重大专项(2024ZD1000705) This research is financially supported by Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(Grant No.2024ZD1000705) （2024ZD1000705）
