Evaluation On The Integrity Of The Injection Production System Of Salt Cavern Underground Gas Storage

As a strategic energy reserve facility,the salt cavern underground storage is widely used in the natural gas energy reserve because of its large throughput,flexible working mode switching and high effective working gas ratio.However,due to the injection and production system may be subject to corrosion,equipment failure,erosion,misuse and other hazards,resulting in stability and safety and stability of gas storage,and even lead to catastrophic accidents.Therefore,it is necessary to systematically study the integrity of the injection system of underground caustic storage system.Based on the extensive literature reading and the field investigation of Jintan gas storage and Pingdingshan gas storage,this paper uses the theoretical analysis,numerical simulation,empirical verification and the combination of existing standard and other methods to construct a sound integrity evaluation system.Using the numerical analysis method to evaluate the column load and residual strength of the injection-production system,and simulate the basic stress environment of the column in the operation of the gas storage;Using the probability neural network method and Monte Carlo simulation to predict the failure probability of the column in the running environment,in order to improve the prediction efficiency and accuracy of the neural network,the Bayesian minimum risk criterion parallel algorithm is used to improve the engineering evaluation efficiency of injection system reliability;designing the FAD failure evaluation model based on fracture mechanics,and calculated the three remaining lifespan of the string integrity of the injection system,including the residual life of the corrosion,the residual life of the entrained salt rock natural gas and the alternating load affect the residual life of fatigue;Finally,the evaluation software of salt cavern underground gas storage integrity was designed and developed.The reliability and accuracy of the proposedmodel are verified by the example of the underground gas storage project of Jintan Salt Cave,which shows that the research results can provide a reliable reference for the engineering integrity evaluation of the injection system of the underground reservoir.Because the engineering condition of the integrity evaluation is more complicated,the research results on the influence of the mixed load of the injection gas on the evaluation of the residual strength of the column are not comprehensive,and the prediction result of the corrosion residual life is more conservative,The above research should be further studied.