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长庆气田开发过程中，硫化氢、二氧化碳、氯离子及水等多种腐蚀介质对井下管柱，地面采、集、输设备会产生不同程度的腐蚀，造成油、套管的断裂，井口装置失灵，集输管线爆破等事故。该气田腐蚀主要有硫化物应力腐蚀和酸性气体的电化学失重腐蚀两类。初期开发的气井由于井底残存部分积液，其中溶有一定量的酸性气体，从而形成酸液对井下管柱的腐蚀破坏。随着气井开发周期的延长，酸液腐蚀过程中产生的Ｈ＋在井下高温高压的作用下将不断地渗入到管柱内，从而降低管柱的硬度和强度，在拉应力的作用下将会造成管柱的应力变形或断裂。为抑制腐蚀介质的腐蚀破坏，建立了气田防腐专项研究项目，从根本上探明长庆气田的腐蚀特点，并借鉴国内其它油气田有关防腐工作的研究结果，开发出适合长庆气田的防腐措施，确保气田长期、高效地开发生产。

CORROSION AND ANTICORROSION IN CHANGQING GAS FIELD

??In the process of developing Changqing gas field,various corrosive media,such as hydrogen sulfide,carbon dioxide,chlorion and water etc.,will produce corrosion to the downhole pipe string and surface producing,gathering and transporting equipments to varying degrees,causing some accidents such as tubing and casing ruptured,wellhead assemble out of order and gathering pipeline burst etc.In this gas field,there are mainly two kinds of corrosion-sulfide stress corrosion and electrochemical weightlessness corrosion by sour gas.Because a certain amount of sour gas has been dissolved in the liquid accumulated at the bottom hole of the gas wells put into production,the corrosion of sour liquid to downhole pipe string has occurred,and along with the prolongation of gas production cycle,the H⁺ produced in the course of sour liquid corrosion will continuously enter into the pipe string under the action of high downhole temperature and pressure,thus dropping the hardness and strength of the pipe string.The deformation by stress or rupture of the pipe string will take place under the action of tensile stress.For controlling the corrosion damage by corrosive media a special research subject for guarding against corrosion in the gas field has been established to thoroughly investigate the corrosion characteristics in Changqing gas field and to develop the anti-corrosion measures suited to Changqing gas field,by using the relevant research achievements of other domestic oil and gas fields for reference,so as to ensure a long-term and high-efficiency production in the gas fields.