Study on array laterolog response simulation and mud-filtrate invasion correction

Abstract

It is a complicated task to evaluate the reservoirs influenced by mud-filtrate invasion. This paper presents the numerical simulation results of array laterolog response and the approach for mud-filtrate invasion correction. Based on the differential equations and boundary conditions of the steady current field in the rock medium, the finite element method (FEM) is applied to solve the Laplace equation, then computing the potential value at each node and calculating the apparent resistivity of six measuring modes of array laterolog. Based on the numerical results, the array laterolog response is affected by many parameters including borehole radius, mud-filtrate resistivity, mud-filtrate invasion radius and invaded area resistivity. Correction charts for borehole and mud-filtrate invasion were made to quickly and accurately obtain the mud-filtrate invasion depth and the true resistivity of the uninvaded formation, which can be used to qualitatively estimate the oiliness and permeability characteristics of the formation. Cited as : Zhao, P., Qin, R., Pan, H., Ostadhassan, M., Wu, Y. Study on array laterolog response simulation and mud-filtrate invasion correction. Advances in Geo-Energy Research, 2019, 3(2): 175-186, doi: 10.26804/ager.2019.02.07