褶皱构造的曲率分析及其裂缝估算--以江汉盆地王场褶皱为例

曲面曲率的几何意义可以反映曲面一点邻近区域的具体形态和变形特征,因而可以用来研究褶皱层面的变形特征、构造样式及其可展性.褶皱面裂缝发育主要为一组张裂系,张裂隙走向与最大主曲率的方向垂直.褶皱构造的主曲率在一定程度上可以反映与褶皱有关的张裂隙的发育情况.对于圆柱状褶皱可以估算与褶皱有关的裂缝孔隙度和渗透率.以王场褶皱构造面为例,通过计算二次趋势面的特征值和特征向量得到褶皱构造面主曲率的大小和方向,确定该褶皱为圆柱状褶皱,并对与之相关的裂缝孔隙度和渗透率进行了估算.

Curvature analysis and fracture estimating of folds--A case study of Wangchang fold in Jianghan Basin

The geometrical meaning of the curvatures of curved surface reflects the shape and deformation characteristics of the adjacent area of one point. It can be applied to study the deformation characteristics, structural mode and developability of a fold. The strike direction of tension fractures developed on a fold is perpendicular to the maximal principal curvatures of the surface. To some extent, the principal curvatures of a fold can reflect the development of tension fractures related to the formation and shape of the folds. For a cylindrical fold, the average aperture and fracture permeability related can be estimated. Based on the fold developed in Wangchang area, this paper obtained the magnitude and direction of principal curvature of the fold by calculating the eigenvalue and eigenvector of the quadratic trend surface, and ascertained that the fold is a cylindrical fold. The average aperture and fracture permeability related to it can also be estimated.