Research on the Evolution Mechanism and Risk Prevention and Control of Leakage Accidents in Depleted Oil and Gas Reservoir-Type Underground Gas Storages

Abstract

With the acceleration of the global low-carbon energy transition, the demand for natural gas continues to grow. As core infrastructure for ensuring a stable natural gas supply, the safety issues of underground gas storages (UGS) are becoming increasingly prominent. In China, depleted oil and gas reservoir-type UGS account for 76%, making them the main type in this field. However, frequent leakage accidents pose a serious threat to the safe operation of UGS. This study takes depleted oil and gas reservoir-type UGS as the research object to systematically investigate the evolution mechanism and risk prevention and control of leakage accidents. Firstly, through statistical analysis of accident cases and expert interviews, the main influencing factors of leakage accidents were identified, including three categories: geological body leakage, injection-production well leakage, and surface facility leakage. Secondly, using the Grounded Theory method, the core categories in the driving stage of leakage accident evolution were extracted, and a conceptual model of driving factors for leakage accident evolution based on the four elements of "Human, Machine, Environment, and Management (H-M-E-M)" was constructed. Thirdly, through system dynamics modeling and numerical simulation, the dynamic evolution law of leakage accidents from initial evolution to secondary disasters was revealed. Finally, from the three dimensions of source prevention, process control, and emergency response, precise whole-process prevention and control measures were proposed targeting the four categories of factors: human, equipment, environment, and management. The research indicates that injection-production well leakage is the main form of UGS leakage, accounting for 57%, followed by geological body leakage (28%). The evolution of leakage accidents is influenced by the coupling effect of the four elements: Human, Machine, Environment, and Management. The constructed evolution mechanism model can effectively reflect the structural characteristics of the leakage accident system. The research results provide a theoretical basis and technical support for the precise identification and efficient prevention and control of leakage risks in depleted oil and gas reservoir-type underground gas storages.