Study On Cavity Deformation And Stability Of Stratified Salt Rock Gas Storage

The salt rock has a good ability of creep deformation at high temperature and pressure environment. The extremely low permeability and the ability of self-reeovery of damage can ensure the tightness and stability of the salt cavern. In order to solve the challenge of peak-shaving and storage in long-distance pipeline, the Jintan gas storages were planed and constructed, parts of which have putted into operation. According to geologic examination of Jintan salt deposit, the deposit of Jintan is layered salt rock, which includes many thin interlayers. Copmaring layered salt rock with pure salt rock, the mechanical properties are different. The paper based on other scholars’experimental research of layered salt rock, the problem of deformation and stability of cavity of salt gas storage during operation by using theory investigation and numerical simulation. The main contents of this paper are as follows:1. According to the possible failure reasons of cavity of salt gas storage from three aspects of stability, leakproofness and reusability, the valuation criteria of layered salt rock gas storage was summarized.2. The deformation, volumetric shrinkage and plastic zone distribution rules of cavities of salt gas storage were analyzed, which has different thickness of interlayers during storing gas in constant pressure.3. To simulate the process of storing gas in constant pressure under the circumstance that the Young’s modulus of interlayer is different. The effect laws of lithologic parameters on volumetric shrinkage and plastic zone distribution of cavities of salt gas storage were studied.4. Assume the working conditions that the gas storage pressure keeps constant as a limit operation state. The three-dimensional model of single cavity of salt gas storage of Jinzi No.1well was set up to study the boundary of storage pressure. According to the use of Jintan gas storages, three operation states were assumed and adopted to simulate the operation of salt gas storage. The volumetric shrinkage of each operation state is obtained by numerical simulation.5. The three-dimensional model of double cavities of salt gas storage was set up. The operation states of storage pressure keeps constant and cyclical variation were studied in double cavities. D/R is the ratio of pillar thickness and maximum diameter. The study finds the effect laws of D/R on average volumetric shrinkage. The best value range of D/R was obtained.