Estimation of the deformation and filtration properties of coal by adsorption test data based on solution of the inverse problem

Abstract

A geomechanical 2D model of the experiment on constrained adsorption deformation of cylindrical rock samples and a numerical-analytical method of solving the corresponding boundary-value problem based on coordinatewise averaging of the system of poroelasticity equations for the orthotropic model of the medium have been developed. It has been shown that the axial and radial deformations measured in the experiment are proportional to the volume-averaged adsorption stresses. Using the results of laboratory testing of coal samples, the coefficient inverse problem of determining the deformation characteristics and permeability of the matrix has been stated and solved. It has been revealed that Young’s moduli of the latter are greater by two or three times and the permeability is at least two orders of magnitude lower than the corresponding effective values for the sample, which is caused by the natural fracturing of coals.