Gas Migration Of Exhaustion Reservoir Gas Storage And Casing String Reliability Study

Underground gas storage could not only solve the contradiction between imbalance demand for natural gas and relatively balanced supply, but also reduce the risk of city pipeline gas supply system, and could solve the problems of national energy strategic reserve and non-uniformity of pipeline gas supply etc. percolation mathematical model for the underground gas storage of exhaustion reservoir was established and corresponding analysis of gas transport was analyzed. In addition, corresponding numerical simulation for the inert gas and cushion gas well casing underground gas storage was conducted, which provide a basis and guidance for the gas storage of exhaustion reservoirs.The flow regularity of gas-water two-phase in oil and gas exhaustion reservoirs was analyzed, and mathematical calculation model based on the equivalent seepage was established. According to the established model, simulation studies of a single well injection process which was provided from domestic underground gas storage of exhaustion gas reservoirs was analyzed. By analyzing the gas dynamic migration law in underground gas storage, It was learned that the permeability rate, the initial reservoir pressure, reservoir porosity and gas injection rates all have a certain impact on gas saturation reservoirs. Among these factors, the initial gas saturation and permeability had more impact on the reservoir, and the reservoir gas saturation increased with the initial gas saturation and permeability increase. With the increase of the initial gas saturation, permeability, initial reservoir pressure and porosity rising, the reservoir pressure will continue to decline, but with the increase of gas injection rate, the reservoir pressure would increase significantly.The study and numerical simulation of cushion gas diffusion law in the exhaustion reservoirs was conducted, and sensitivity of the reservoir parameters was analyzed. Finally, reliability study of casing string used in underground gas storage of exhaustion reservoir was conducted. The parameter sensitivity of casing string was analyzed by the numerical simulation, and corresponding conclusions was concluded at the same time.