酸蚀裂缝表面微凸体变形破碎规律

摘要

探讨酸蚀裂缝面上微凸体在地层应力作用下变形破碎规律,为酸蚀裂缝闭合机理提供理论依据.从初始和酸蚀后裂缝表面微凸体的受力分析入手,用Herz弹性接触理论和Drucker-Prager屈服破坏准则解释了酸蚀裂缝表面微凸体变形和破碎规律,结果表明,在地应力条件下初始裂缝表面微凸体受力平衡不会发生变形破碎,酸蚀后裂缝表面微凸体在承压时的变形程度与地应力、岩石的弹性模量及酸蚀后微凸体的曲率半径有关.当酸蚀后裂缝面微凸体的曲率半径大于其发生破碎的最小曲率半径时,酸蚀裂缝可保持较大的开度及导流能力.%The study of the deformation and crush law of the microbulges on the surface of the acid-etched fracture under the crustal stress provides a theory basis for the acid-etched fracture closing mechanism. Based on the former analysis of the microbulges on the surface of the fracture before and after being acidized, the deformation and crush law of microbulges on the surface of the acid-etched fracture is explained by the Herz elastic contact theory and Drucker-Prager yield criterion. The result shows that the initial force of the microbulges on the surface of the fracture is balanced under the crustal stress so that the deformation and crush will not occur. The deformation degree of the microbulges is affected by the crustal stress, the elastic modulus of rock, the curvature radius of the acid-etched microbulges after being acidized. When the curvature radius of the acid-etched microbulges is greater than the minimum crush radius rmin, the acid-etched fracture can maintain a bigger aperture and a better diversion capacity.