The feasibility analysis of underground gas storage caverns

This paper presents the fuzzy concept for the feasibility analysis of Underground Gas Storage (UGS) designed from Lined Rock Caverns (LRC). For this purpose, it is necessary to carry out a number of steps. The first is the determination of the geological model of the UGS region. The next is transferring of the geological model into the geomechanical model, which could be achieved by applying the system of Hoek and Brown based on the geological strength index (GSI). The equivalent Mohr–Coulomb strength parameters should be determined. The geomechanical analysis for risk during construction and later during operation of UGS using Finite Element Method (FEM) is carried out. The series of FEM analyses should be calculated for the determination of changes in the response functions due to changes in the design variables. The results of FEM analyses are given in table form. The cost of UGS is calculated with developed equations. The construction costs comprise the investment and operational costs of the UGS system. The total construction costs per unit of gas include the sum of fixed costs and variable costs. Once the results of FEM and cost analysis are obtained, we use those solutions to develop ANFIS models. In this paper the ANFIS model for cost prediction is described in detail and the similar procedure is used to develop geomechanical constrain functions. These models are the basis for the feasibility analysis of underground gas storage caverns.