1　编制背景和过程1 .1　西气东输工程是将我国西部地区的天然气通过管道输往急需清洁能源的东部地区 ,既满足东部地区对天然气能源的要求 ,又发展了西部经济 ,是东西部经济发展的系统工程。此输气管道全长 40 0 0多公里 ,材质 X70 ,规格为 1 0 1 6× 1 4.6～ 2 6.2 mm,工作压 1 Background and process of preparation 1.1 The project of transporting natural gas from the western region to the east of the area urgently needed for clean energy by natural gas in the western part of China will not only meet the requirements for natural gas energy in the eastern region but also develop the economy in the western part of the country, Systematic engineering of economic development. The gas pipeline is more than 40,000 kilometers in length with a material of X70 and specifications of 1 0 1 6 × 1 4.6 to 2 6.2 mm and working pressure