Research On Feasibility Of Constructing Da5 Aquifer Underground Gas Storage In Jizhong Depression

Aquifer underground gas storage(UGS) is the second large scale UGS other than depleted UGS, the technical difficulties, security risks, project investment and construction period for building an aquifer storage should be higher than that of depleted dry gas reservoir storage, there is no precedent for UGS constructed by aquifer in our country until now and also lacking of practical knowledge and experience, however, sealing efficiency and trap integrity is the basic precondition and theoretical basis of storage site selection and storage design.This study based on Da5 block, focus on the core issue of caprock sealing efficiency,reservoir property and trap efficiency to conduct four aspects research which are geological characteristics, gas reservoir engineering, indoor experiment and field test. Through these research to evaluate the feasibility for building an aquifer UGS, the main results achieved and understanding are as follows: generalize the influence factors of caprock sealing efficiency,establish an initial evaluation standard, evaluate Da5 mudstone caprock sealing efficiency through geological, dynamic and experiment; evaluate reservoir properties and flow characteristics based on indoor experiment and productivity test; research on reservoir property lower limit determination method, in the meanwhile use displacement pressure method and minimum pore-throat radius for reference to determine an initial reservoir property lower limit of Da5 storage; determine storage parameters and make storage injection-production pattern arrangement.This paper has some important theoretical and practical values in the research on aquifer UGS construction, study results provide a scientific basis for site selection, designation,sealing efficiency evaluation and rational injection-production parameters determination of aquifer UGS.