中国地质2025，Vol.52Issue(2)：425-437,13.DOI:10.12029/gc20230901003
青海共和盆地干热岩GR2井现今地应力特征及断层稳定性分析
In-situ stress characteristics and fault stability analysis of hot dry rock GR2 well in the Gonghe Basin,Qinghai
摘要
Abstract
This paper is the result of geological survey engineering. [Objective]The magnitude and direction of in-situ stress are important parameters for well placement,fracturing design and reservoir evaluation in hot dry rock development.It is of great significance to study reservoir stress state for hot dry rock development.[Methods]In this paper,the characteristics of current stress field in the Gonghe Basin are analyzed based on regional geological structure evolution,focal mechanism solution and inversion results,statistics of joints and fissures,and in-situ stress measured data.Combined with the reservoir structure and stratigraphic lithofacies characteristics of GR2 well,a three-dimensional model is established,and the three-dimensional in-situ stress data of GR2 well in the Gonghe Basin is obtained through numerical simulation by using orthogonal anisotropic elastic constitutive relation.The regional tectonic stress field and occurrence conditions of dry hot rock resources are discussed.[Results]①The simulated stress distribution is consistent with the theoretical value,which meets the requirements of initial displacement accuracy,and finally predicts the distribution characteristics of in-situ stress field in the well.②In the depth range of 500～4500 m,the relationship of three principal stresses is principal stress is σv>σH>σh,indicating that the stress structure in this region is favorable to normal fault activity.③The maximum horizontal principal stress direction of the Gonghe Basin in Qinghai province is mainly NE direction compression deformation,which is conducive to low fluid permeability and low heat transfer of granite.④Under the action of a unified regional stress field,the faults may be come instability near the injecting well,when the continuous injection pressure on the ground reaches or exceeds about 19.9 MPa during the water injection development of 3900～4500 m depth in the study area,leading to the occurrence of medium and small earthquakes,which should be prevented in the development and utilization of the hot dry rock.[Conclusions]The research results have certain reference value for geodynamics research and the safe development and utilization of dry hot rock in the Gonghe Basin.关键词
干热岩开发/地应力/三维数值模拟/断层活动性/地质调查工程/共和盆地/青海省Key words
the development of hot dry rock/in-situ stress/3D numerical simulation/fault activity/geological survey engineering/the Gonghe Basin/Qinghai Province分类
地球科学引用本文复制引用
陈东方,杨跃辉,牛兆轩,王红伟,金显鹏,李振宇,吴海东,刘东林..青海共和盆地干热岩GR2井现今地应力特征及断层稳定性分析[J].中国地质,2025,52(2):425-437,13.基金项目
国家重点研发计划(2021YFB1507404)及中国地质调查局项目(DD20211336、DD20230018)联合资助. Supported by the National Key Research and Development Program(No.2021YFB1507404)and the projects of China Geological Survey(No.DD20211336,No.DD20230018). （2021YFB1507404）
