Study On Risk Assessment Technology Of Oil And Gas Pipeline Jacking Through River

In recent years, along with the rapid growth of oil&gas demand, the oil&gas pipelines construction is also increasing year by year. Inevitably, The long-distance oil&gas pipelines are through the complex terrain, for example railway, highway, river and other obstructions. The crossing construction can solve this problem. Pipe jacking construction is a kind of underground crossing construction method which has many advantages, such as construction of high precision, wide use in various soil, low cost, little environmental pollution and also can cross through the rivers, highway, railway, airport runways and other obstructions.So, the pipe jacking construction is widely used in the construction of oil&gas pipelines crossing. But the pipe jacking construction is hidden underground engineering whose risk factors should be more than the ground construction. Besides, the underground conditions are very complex and the possibility of the occurrence of safety accidents is higher than the ground construction. Therefore the purpose of this paper is to develop a suitable for oil&gas pipelines risk assessment technology in construction of pipe jacking crossing the river.In order to realistically evaluate the risk of oil&gas pipelines pipe jacking crossing the river construction, a risk evaluation method was worked out based on portfolio weighting attribute recognition model. According to the characteristics and the construction sections of pipe jacking, it will be divided into8sections to start risk assessment. Then, the pipe jacking construction and risk assessment can start at the same time. Firstly, fault tree analysis is used to identify risk factors of8construction sections and establish fault tree, so as to identify the main risk factors of8construction sections of pipe jacking. Secondly, establishing attribute space matrix which was ordered partition, in order to overcome the shortcomings of simple weighting, using the portfolio weighting of objective entropy and subjective G1to assure the empower weight and attribute measurement of evaluation indicators. The confidence criterions are used to recognize the categories of construction sections and obtain the possibility of construction sections failure, then according to casualties, construction lost and construction period determined the result of construction sections failure. Finally, establishing the risk matrix to obtain the risk rank of pipe jacking construction.Meanwhile, in this article, risk control method for pipe jacking contruction of oil&gas pipelines is preliminary discussed to reduce its risk rank. First of all, the risk control methods were applied to pipe jacking construction, then risk mitigations method for risk factors of pipe jacking construction sections were used to medium and high risk sections, which ensure pipe jacking construction sections meet the risk criteria and safe construction.