Wen 96 Underground Gas Storage Risk Assessment Technology Research

With the rapid development of natural gas industry,underground gas storage,as a tool for natural gas storage and peak shaving,plays a more and more important role in the production and transportation process of natural gas.Among the underground gas storages around the whole world,the depleted underground gas storage occupies a large proportion.At present,most of the 25 underground gas storages in China are depleted underground gas storages.During the operation of gas storage,the failure probability of underground gas storage is increased by factors such as alternating load,geology and engineering.Due to the high operating pressure,the underground gas storage failure will cause serious consequences.As the first depleted underground gas storage in Sinopec,Wen 96 underground gas storage has a very important position both in its cultural location and in the process of natural gas transportation.As the domestic and international researches on the risk assessment technology of depleted underground gas storages are now lagging in phase,the research on the risk assessment technology of Wen 96 underground gas storage is of great significance.Based on the research of relative domestic and foreign literatures and the present situation of Wen96 underground gas storage,the paper identified the risks of Wen 96 underground gas storage;The failure probability model and the failure consequence model are established to analyze the failure probability and failure consequence of the ground and underground engineering facilities and systems of Wen 96 underground gas storage;The classification standard,the failure consequence classification standard and the risk classification standard of the gas storage failure probability are established,the risk assessment of Wen96 underground gas storage is completed and relevant suggestions are given.By using API 581 similar failure probability model and evaluating Wen 96 ground engineering equipment from two aspects(the equipment modification coefficient and management correction coefficient),the research of the failure probability of ground engineering facilities is completed;Through the establishment of the system failure probability model,the research on failure probability of ground engineering subsystems of Wen96 underground gas storage is accomplished.During the study of Wen 96 underground engineering facilities,the fault tree failure probability model,based on HAMA operator,is established by considering transfer correlation between basic events and the correlation of the minimal cut sets;By using the classical expert judgment basic events fuzzy probability model,through dividing the expert's ability value by scoring method,obtaining the triangular fuzzy number of basic events by fuzzy aggregation method,obtaining the basic event failure probability by fuzzy transformation,the failure probability of underground engineering facilities and system of Wen96 underground gas storage is hence calculated.This paper used API 581 failure consequence assessment method,through calculation of leak rate under four kinds of leakage size in defined failure scenarios and combined with failure consequence assessment method,to complete the analysis of Wen96 underground gas storage ground facilities failure consequence;The TNT equivalent model is used to analyze the failure consequences of injection and production wells and geological structures of Wen96 underground project;Through the establishment of the system failure consequence model,the failure consequence analysis of subsystems of Wen96 underground gas storage is completed.In this paper,the risk assessment of Wen96 underground gas storage is completed and relevant advice is given by establishing the classification standard of the failure probability,the classification of the failure consequence,and the risk grade classification standard;The damage criteria of heat radiation,overpressure and toxicity of Wen96 were determined,the PHAST software was used to simulate the fire consequence model,the fireball consequence model,the explosive consequence model and the toxic consequence model of equipment in Wen96,and the corresponding suggestions are given according to the simulation results.