Risk Evaluation Of Oil And Gas Transmission Pipelines Engineering Above Gob Affecting Zone

In recent years, with substantial demand for oil and natural gas resources ,oil and gas pipeline project in China has entered a peak period, oil and gas pipeline project because of its big extended length, and inevitably crosses the widely distributed coal gob area. The surface movement and destruction above gob affecting zone brings special difficulties to the construction of oil and gas pipeline. Study on risk evaluation of oil and gas transmission pipeline engineering above gob affecting zone, not only has important theoretical significance to ensure the security operation of oil and gas pipelines in the design life, but also has universal guiding significance for the oil and gas pipelines how to pass through the coal gob affecting area in future, and take full use of the underground mineral resources.Subject based on coal gob along the West-East gas transmission pipeline project, analyzed roundly the main factors of the surface damage caused by gob, Classified the gobs according to its characteristics by the mining method, the ratio between mining depth and mining thickness, the formation time and stop time of gob. Analyzed the relationship between surface movement and deformation and pipelines deformation. Also gave the prediction method of surface residual movement and deformation and the theory method of evaluating coal pillar strength suitable for different types of gob. It has created evaluation indicators, which includes mining method, the formation time of gob, lithology of overlying rock and the ratio between mining depth and mining thickness. Judge the risk of gob affecting zone by surface movement and damage indicators and divide the different dangerous levels. Combined the capacity of the anti-deformation of pipeline and the indicators of surface deformation as well as relevant research results at home and abroad, it set up the risk evaluation system of oil and gas pipeline above gob affecting zone for the first time. It has carried out the whole process by Visual C++ program, put forward reasonable disposal methods and protection measures for different levels. This paper relies on the affected situation on JiNing branch of West-East gas transmission pipeline, which caused by gob of XingLongZhuang Coalmine in YanZhou mining area. It demonstrates the example, and indicates that the results from the risk evaluation indicators system of oil and gas pipeline above gob affect zone coincide with the actual situation. At the same time it gives reasonable disposal methods.