Risk Assessment And Management Of The Deep Layer Salt Rock Underground Gas Strorge

The salt rock has the properties of low permeability, creep behavior, damage self-healing ability and other good character istics; therefore it can provide a good storage cavern of natural gas with leakproofness and stability in spite of the dynamic stress. And it has become a common understanding worldwide that salt rock makes good natural gas storage. In recent years, China has also embarked on site selection and construction work of the underground energy reserves in salt rock caverns. Compared with other underground gas storages, salt rock caverns have better security. In the past3decades, however, disastrous accidents did frequent the salt rock storages of oil and gas, resulting in leakage, cavity failure, ground subsidence, and other disasters, conseque ntly seriously threatening the environment and people's safety. Nevertheless salt mines in China are characterized as coMParati vely shallower burial depth, lower thickness, multiple interlayer, lower grade and etc. Constructing gas storage caverns in those above situations means more difficulties and risks, and many scientific issues to study about, particularly in the risk assessment and management.This paper focused on the following research:(1)Statistic analysis of salt rock underground gas storage risk events has been done, and The main risk factor has been introduced in this paper. The risk of underground storages has been identified, attained the main risk factors.(2) Performance function of rock salt underground gas storage shear failure was constructed based on the Mohr-Coulomb failure criterion. The calculation mothod of the salt rock underground gas storage shear failure probability has established on improved FOSM method.(3) Performance function of rock salt underground gas storage leakage was constructed based on expansion of the boundary line of rock salt damage. Based on response surface-Monte Carlo method, the failure probability of underground gas storage leakage calculation method was established.(4) The over convergence performance function has been constructed. Based on response surface-Monte Carlo method, the failure probability of underground gas storage over convergence calculation method was established.(5) Recognize surface subsidence as the results of the mining space spreading, the sinking root function and sinking spread influence function was used to predict the surface subsidence, thereby the failure probability of underground gas storage surface subsidence calculation method was established.(6) Risk has been assessed onJitan salt rock underground gas storage, the failure probability results under different failure modes has been gotted.(7)This paper defines different levels of stability according to different failure possibilities and establishes a matrix to assess the risks of underground gas storages in salt rock. The Underground Salt Rock Gas Storage Risk Information Management and Assessment has been developed under the aids of the matrix, By means of that system, the risks of Jintan underground salt rock gas storage is graded.