Risk Assessment for Underground Natural Gas Storage in Depleted Oil and Gas Reservoirs

Underground gas storage in depleted oil and gas reservoirs is the most widespread and the least expensive method to store natural gas, which is a vital component of energy supply in the world. Natural gas leakage from the storage is the major hazard to take into consideration. The deep researches on the risks associated with gas leakage are of great significance. These risk factors are identified as 9 consolidated categories and 31 specified risks to draw lessons from risk assessment methods of pipeline as well as carbon dioxide capture and storage. According to the statistics and analysis of previous accidents at gas storage, fault tree analysis is used to investigate 14 main risk factors that led to leakage accidents. On this basis, the corresponding risk mitigation actions are presented. The risk assessment methodology will provide crucial inputs as decision making support for storage owners and managers to deal with the possible occurrence of gas leakage.