Owing to perfect impermeability,dynamics stability,flexible and efficient operation mode and strong adjustment,underground salt cavern natural gas storage is especially adapted to be used for short-term dispatch.Based on characteristics of gas flow and heat transfer,dynamic mathematic models were built to simulate the injection and withdrawal performance of underground salt cavern gas storage.Temperature and pressure variations of natural gas in gas storage were simulated on the basis of building models during withdrawal operation,and factors affecting on the operation of gas storage were also analyzed.Therefore,these models can provide theore-tic foundation and technology support for the design,building and operation of salt cavern gas storage.
Aimed at the problem of mixing working gas and cushion gas in carbon sequestration technology, the feasibility of using carbon dioxide as the cushion gas in reservoirs is discussed firstly. At the usual condition of reservoirs, carbon dioxide is a kind of supercritical fluid with high condensability, high viscosity and high density. Secondly, this article studies the laws of formation and development of mixing zone by numerical simulation and analyses the impact on mixing zone brought by different injection modes and rational ratios of cushion gas in reservoirs. It is proposed that the appropriate injection ratio of cushion gas is 20%-30%. Using carbon dioxide as cushion gas in gas reservoirs is able to make the running of natural gas reservoirs economical and efficient.
