摘要
地应力的大小及方向对深部煤层气开发影响显著。以鄂尔多斯盆地东缘临兴西区为例,基于实验测试、井壁崩落法和断层摩擦系数地应力法,分析了三向主应力的方向与大小,阐释了地应力的基本特征及其空间发育规律。结果显示:8号煤层垂向应力S v介于44.94~50.46 MPa,平均48.47 MPa;水平最大主应力S H介于35.16~44.53 MPa,平均40.62 MPa;水平最小主应力S h介于28.79~39.45 MPa,平均33.02 MPa。9号煤层垂向应力介于45.03~50.46 MPa,平均48.57 MPa;水平最大主应力介于35.33~44.53 MPa,平均40.69 MPa;水平最小主应力介于29.01~39.45 MPa,平均33.11 MPa。误差分析显示此地应力计算结果可靠。三向地应力大小与埋深呈正相关关系。在垂向上,三向地应力相对大小表现出明显分带性,即埋深<1000 m左右为S h<S v<S H为特征的剪切型地应力带;埋深介于1000~1800 m表现为S h<S H<S v过渡带;埋深>1800 m表现为S h<S H<S v为特征的正断型地应力带。在平面上,地应力在平面上总体呈西北部低、中部与南部高、其余地区适中,主要在T-23-2井和T-19井区存在应力低值带。最大水平主应力地应力方向主要以EW-NEE向为主。地应力场的阐释将为研究区深煤层储层物性评价、勘探选区及钻完井工程设计提供地质参考。
The magnitude and direction of crustal stress have a significant impact on the development of deep coalbed methane.This work measured these two parameters in the western Linxing area of Ordos.Basin based on experimental tests,the borehole caving method and the fault friction coefficient method.The direction and size of the three principal stresses were analyzed,and the basic characteristics and spatial development laws were explained.The results show that the vertical stress S v of No.8 coal seam is between 44.94 and 50.46 MPa,with an average of 48.47 MPa;the maximum horizontal principal stress S H is between 35.16 and 44.53 MPa,with an average of 40.62 MPa;and the minimum horizontal principal stress shis between 28.79 and 39.45 MPa,with an average of 33.02 MPa.The vertical stress of No.9 coal seam is between 45.03 and 50.46 MPa,with an average of 48.57 MPa;its maximum horizontal principal stress is between 35.33 and 44.53 MPa,with an average of 40.69 MPa;and the minimum horizontal principal stress is between 29.01 and 39.45 MPa,with an average of 33.11 MPa.The error analysis shows that the stress calculation results are reliable.The magnitude of the crustal stress is positively correlated with the burial depth.In the vertical direction,the relative magnitude of the three principal stresses shows obvious zoning,that is,the shear-type stress zone characterized by S h<S v<S H with a burial depth<1000m,and the burial depth is between 1000~1800 m.The S H<S v transition zone and the buried depth>1800 m represent a normal fault stress zone characterized by S h<S H<S v.In the plane,the crustal stress is generally low in the northwest,high in the middle and south,and moderate in the rest.Low stress values are present in wells T-23-2 and T-19.The maximum horizontal principal stress is mainly in EW-NEE direction.The interpretation of the crustal stress field will provide a geological reference for the physical properties evaluation,choice of exploration areas and drilling-completion engineering design of deep coal seam reservoirs in the study area.
作者
张和伟
申建
李可心
赵锦程
徐延勇
ZHANG Hewei;SHEN Jian;LI Kexin;ZHAO Jincheng;XU Yanyong(Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou,Jiangsu 221000;School of Resources and Geosciences,China University of Mining and Technology,Xuzhou,Jiangsu 221116;China United Coalbed Methane Co.,Ltd.,Beijing 100011)
出处
《地质与勘探》
CAS
CSCD
北大核心
2020年第4期809-818,共10页
Geology and Exploration
基金
国家自然基金(编号:41872171、41672149)
国家重大科技专项(编号:2016ZX05066001-004)联合资助。
关键词
深煤层
井壁崩落法
断层摩擦系数法
地应力
应力类型
临兴西区
鄂尔多斯盆地
deep coal seam
well wall caving method
fault friction coefficient method
crustal stress
stress type
western Linxing area
Ordos Basin
