Estimation of parameters of gas storage operation in inhomogeneous aquifers

Abstract

The purpose of the article is development and testing of a mathematical model of gas storage in a layered aquifer with a low permeabilityinterlayer for a case of plane-parallel and axial-symmetric filtration. Methodology. One of the most common models of anisotropy of rocks is a model of a layered seam, which is explained by geological conditions of sedimentation, which lead to stratification of layers with different collecting properties. In the practice of underground gas storage, consideration of such a model is of particular importance.This is due to possible significant difference in advancing a boundary of gas-water contact through the interlayers with different filtration characteristics caused by changes in a position of a gas zone. A comprehensive approach is applied, which includes collection, systematization and analysis of actual data on filtration and physical and mechanical properties of host rocks that affect the formation of natural and technogenic deposits, as well as analytical and numerical methods for solving equations of gas-water contact in different conditions. Results. Gas-hydrodynamic model of underground gas storage in an inhomogeneous aquifer is justified for calculation of its cyclic operation in a three-layer seam considering cross-flows through a low permeability interlayer.The results can be used in evaluation calculations at a design stage of gas storage facilities in aquifers. Scientific novelty. A mathematical model of gas storage in a layered aquifer with a low permeability interlayerfor a case of plane-parallel and axial-symmetric filtration is developed and tested. A new method of linearization of a system of differential equations for determining pressures in a collectingseamis obtained in the article and it is a generalization of previously used methods, with an introduction of "boundary schemes". Practical significance. Calculation results indicate a significant influence of characteristics of a layered porous medium on the advance of gas-water contact along individual layers. The results can be used in the evaluation calculations at a design stage of gas storage facilities in aquifers.