A study on the dual laterolog response to fractures using the forward Numerical modeling
用正演数值计算方法开展双侧向测井对裂缝的响应研究

We use ANSYS, a large general finite element method software, to compute the dual laterolog response to parallel fractures of equal spacing in the carbonate formation crossing a borehole. The relationship between the dual laterolog response and fracture porosity, fracture dip-angle, base rock resistivity and fluid resistivity are discussed. Based on the analysis of numerical simulation results and the characterizations of dual laterolog response to fractures, a new method is developed to classify the forms of fractures, which can dynamically change the definition of fracture dip-angle range to fit different instances. The technique to obtain the approximate dip-angles of fractures with dual laterolog response is realized. It can greatly prove the estimation of fracture porosity (aperture of fracture). With the condition of constant fracture dip-angles, the inversion model of the dual laterolog response and formula for computing fracture porosity are presented.