摘要
地应力大小和方向是干热岩开发中注采井网部署、水力压裂设计和诱发地震评估等方面的重要基础数据。本文利用非弹性应变恢复(ASR)地应力测试方法,实测获取了唐山市乐亭县马头营干热岩勘探区3~4 km深度范围的地应力状态。研究结果表明:①地应力量值随深度增加而加大,3139~3934 m深度范围内水平最小主应力介于59.0~90.7 MPa之间,水平最大主应力介于103.7~123.6 MPa之间。水平最大主应力方向介于N83°~114°E之间。②三向主应力总体表现为σ_(H)>σ_(v)>σ_(h),表明研究区3~4 km深度构造应力占主导地位,该应力状态有利于走滑断层活动。③利用摩尔-库伦准则对邻区断层的稳定性进行分析,结果表明研究区3~4 km深度范围内的断层总体处于稳定的应力环境。④干热岩注水开发与断层稳定性分析表明,在统一的区域地应力场作用下,研究区3900~4000 m干热岩注水开发过程中,当地面持续注入压力达到或超过约28 MPa时,可能引起场区内断层的滑动失稳,导致中小地震的发生,在干热岩开发利用中需注意防范。研究结果对于唐山地区地球动力学研究及干热岩的开发利用具有一定的参考价值。
The magnitude and direction of in-situ stress are important parameters in the deployment of injection production well pattern, the design of hydraulic fracturing simulation, and the evaluation of induced earthquakes. The Anelastic Strain Recovery(ASR) in-situ stress measurement method was employed to obtain the in-situ stress state in 3~4 km depth of dry hot rock in the Matouying area, Laoting County, Tangshan City. The results show that:① the magnitude of in-situ stress increases with depth within a range of 3139~3934 m depth, the minimum horizontal principal stress is 59.0~90.7 MPa, the maximum horizontal principal stress is 103.7~123.6 MPa, and the maximum horizontal principal stress direction is N83~114°E.② The relationship of three principal stresses is σ_(H)>σ_(v)>σ_(h), which indicates that the tectonic stress field gives priority to the horizontal stress, and the stress state is favorable for activity of strike-slip faults.③ The result of stability of the fault studied according to Mohr-Coulomb criterion, shows that the ratios of shear to effective normal stress are lower than those from Byerlee’s law, indicating that the faults are in the relatively stable stress environment near the well M1 in Matouying area within a depth of 3~4 km.④ The analysis of the relationship between the water injection and fault stability shows that the faults may become unstable near the injecting well, when the continuous injection pressure on the ground reaches or exceeds about 28 MPa during the water injection at 3900~4000 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 dry hot rock. This study has certain reference value for the analysis of geodynamics and the development and utilization of dry and hot rocks in Tangshan area.
作者
上官拴通
孙东生
张国斌
杨跃辉
齐晓飞
陈东方
乔永超
李阿伟
陈群策
SHANGGUAN Shuantong;SUN Dongsheng;ZHANG Guobin;YANG Yuehui;QI Xiaofei;CHEN Dongfang;QIAO Yongchao;LI Awei;CHEN Qunce(Hebei Coalfield Geology Bureau Second Geological Team,Xingtai,Hebei 054000,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Key Laboratory of Active Tectonics and Crustal Stability Assessment,Beijing100081,China;China University of Geosciences,Beijing100083,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2021年第12期3915-3925,共11页
Acta Geologica Sinica
基金
河北省重点研发计划项目(编号19274102D)
河北省创新能力提升计划后补助项目(编号205A4101H)联合资助的成果。
关键词
唐山地区
地应力
非弹性应变恢复法
断层活动性
干热岩开发
Tangshan area
in-situ stress
anelastic strain recovery method
fault activity
the development of dry and hot rocks
