韩城区块西北部三维地应力场反演分析

Inversion analysis of three-dimensional geostress field in northwest Hancheng Block

为改善当前地应力场研究对经验公式的依赖现状,以韩城区块地质条件为背景,提出了通过有限元反演回归计算地应力的方法,根据韩城区块的地质概况建立起较为精确的三维地质模型,以现场水压致裂法所测得的地应力实测资料为基础,采用三维有限元回归分析法拟合实测数据,得到研究区的地应力场分布规律。研究结果表明:煤层三向应力从大到小依次为垂向应力、水平最大主应力、水平最小主应力;煤层的整体应力差处于2~4 MPa之间,在北西部存在较大应力差;煤层整体的应力方向趋势呈北偏东45°;误差大小不超过20%,能够满足工程实际的要求。

In order to improve the current situation of relying on empirical formulas in the current research on goestress fields,a finite element inversion and regression calculation method of goestresss is proposed based on the geological conditions of Hancheng Block.First,a more accurate three-dimensional geological model is established according to the geological situation of Hancheng Block;the three-dimensional finite element regression analysis method is used to fit the measured data,and finally the distribution law of the goestress field in the study area is obtained.The research results show that the three-dimensional goestress of the coal seam is in descending order:vertical stress,horizontal maximum principal stress,and horizontal minimum principal stress;the overall stress difference of the coal seam is between 2 MPa and 4 MPa,and there is a larger stress in the northwest;the overall stress direction trend of the coal seam is 45 degrees north to east;the error size does not exceed 20%,which meets the actual requirements of the project.