Study On Quantitative Risk Assessment For The Long-Distance Oil/Gas Pipelines In Service

This thesis aims at the characters of the long-distance pipelines in service at home, goes at the framework of quantitative risk assessment for the oil/gas pipeline and studies the quantitative risk assessment technology respectively from three aspects, i.e. risk analysis, risk estimate, and risk decision-making. Ultimately, a set of theory and methods with regard to quantitative risk assessment for the long-distance oil/gas pipeline in service are developed.This thesis includes 11 chapters.The 1st chapter is the introduction. The background and signification of this study are expounded. The study actuality, study development and main methods of oil/gas pipeline risk assessment are analyzed. The disadvantages and difficulties in existing methods are pointed out, too are the study objects, the study contents and the study technique route etc.The 2nd chapter analyzes the system of the risk assessment for oil/gas pipelines. The concepts related to the pipelines risk assessment are defined. The frameworks of quantitative risk assessment and risk analysis are analyzed.The 3rd chapter carries through the hazard distinguish about the oil/gas pipelines. The concepts related to hazard distinguish, general processes and the principle of the Fault Tree Analysis (FTA) are analyzed. This chapter sets the FTA of oil/gas pipelines, and distinguishes the main effect factors that cause the iailure of the pipeline through the qualitatively analysis of the FTA.The 4th puts forward two calculation methods for pipeline failure probability, which is one of the study emphases. The concepts related to the pipeline failure probability are defined. Improved expert judgment method is brought forward and applied to confirm the fuzzy failure probability of pipeline basic events. In this method, AHP is inducted to confirm the weighs of the experts' sights to modified the experts' sights. The failure probability models are established respectively based on the independency and dependency of basic events. In addition according to structure reliability principles, the reliability probability model aimed to the pipes with corrosion defects is also built.The 5th chapter introduces the calculation methods of relative failure consequence and relative risk for the oil/gas pipelines. Effect factors and characters of hazard caused by oil/gas pipeline failure are analyzed, and accordingly the relative failure consequence and relative risk are reckoned. The principle and method of risk profile picture are put forward to see the integrity risk situation of the pipeline system.The 6th chapter studies the quantifying methods of pipeline failure consequence and risk, which is another study emphasis. Effect factors and characters of fire explosion hazard caused by oil/gas pipeline leakage are analyzed. Fire explosion is assessed quantitatively based on the liquid character of the product leaked. The hazard range is confirmed though confirming the range of the four types of destroys, based on which the individual risk and society risk are quantified. Also, the method of risk acceptance estimate is brought forward. This method setsup the critical estates to estimate the acceptance of risk.The 7th chapter simply analyzes the measures reducing the risk of oil/gas long-distance pipelines in service, including cleaning pipeline, inspecting pipeline, maintaining pipeline and Managing Pipeline etc.The 8th chapter put forward the maintenance resources distribution technology, namely risk-based decision-making optimization for oil/gas pipeline integrity maintenance, which is the third study emphasis. According to the actuality of oil/gas pipeline risk assessment, the study range and emphasis are analyzed firstly. Then two processes of this method system prioritizing and decision-making analysis are illustrated. Afterward the mathematical model of pipeline integrity maintenance decision-making is established. Based on the charge and utility function, the methods of decision-making optimizing for oil/gas pipeline integrity maintenance is put forward emphatically. Furthermore...