Study on the Production Mode and Leakage Risk of Gas Storage Well Completion

The construction of natural gas storage reservoir can effectively guarantee the seasonal peak demand of natural gas, but at present, the research on the construction of gas storage reservoir and the prediction of production and leakage risk is not comprehensive. Therefore, through the analysis and study of typical completion string, production mode and leakage risk of gas storage, the characteristics of different types of gas storage reservoirs are obtained. Among them, salt cavern gas storage reservoir mainly uses water-soluble cavity technology to store natural gas in salt cavern formed after the underground brine is extracted. The cavitations stage is completed by the auxiliary construction of water injection string+brine discharge center pipe. After the discharge of halogen, the central pipe is lifted out through non-kill well equipment and then the gas injection underground storage is carried out. This type of gas storage reservoir has the characteristics of high gas discharge rate, low base gas quantity, strong corrosion resistance of pipe column but high leakage risk. Compared with the salt cavern storage, the production string of the gas reservoir is mainly composed of packer, underground safety valve and gas seal tubing, and the production well seat sealing under the waste oil reservoir is used for gas injection and extraction. In addition, this paper also establishes a gas leakage annular zone pressure mathematical model based on one-dimensional gas migration equation, which can effectively predict the permeability of leakage points through well pressure test values and calculated values, and effectively evaluate the leakage risk of gas storage.