Available target evaluation of underground gas storage based on AHP-FCE methods

Abstract

Underground gas storage (UGS) is one of the feasible technologies to achieve carbon emission reduction and reach the carbon peak target. The scientific evaluation of available UGS targets is still challenging due to uncertainty of caprock, reservoir, fracture, etc. To fill this gap, this work develops an efficient evaluation method to determine the available UGS targets based on oil or gas reservoirs by Analytic Hierarchy Process (AHP) and Fuzzy Comprehensive Evaluation (FCE) method. An integrated evaluation system for potential UGS is formed, including the evaluation indicators, scoring criteria, and the workflow of available target applicability evaluation. Field application is performed to validate the proposed model. The selection of target blocks is performed by a multi-factor evaluation method (AHP-FCE), and an evaluation index system and the evaluation criteria are proposed. The indicators are more completed, including 6 indicators and 44 sub-indicators. The assessment matrix has passed the consistency check because of CR<0.1. The factors of caprock and reservoir yield greater impact on the UGS siting. Field case shows that the excellent membership degree of Block # A and #B are 0.315 and 0.574, suitable for potential UGS. The average membership degree of Block # C and #E are 0.591 and 0.386. The poor membership degree of Block # D is 0.422. The evaluation model can provide accurate and objective technical support for UGS target evaluation.