新疆油田呼图壁储气库气井管柱腐蚀实验研究

新疆油田公司依据中石油股份公司储气库建设要求,启动了＂呼图壁气田改建储气库＂建设工作。储气库的主要气源是从土库曼斯坦进关的天然气,该天然气中CO2≤2%,CO2分压最大为0.68MPa,采出时在井口及井底,天然气的含水量普遍高于对应温度、压力下的天然气饱和含水汽量,即低于露点温度,会导致较为严重的CO2腐蚀。通过分析知道呼图壁气田影响二氧化碳腐蚀的环境影响因素主要有二氧化碳分压、地层水矿化度及Cl-含量、温度、流速等,由此设计了室内模拟实验条件;评价了P110、3Cr110、普通13Cr110、HP1-13Cr110抗CO2（含Cl-）腐蚀性能。得到了室内模拟条件下,不同目标管材的平均腐蚀速率与局部腐蚀速率,根据实验结果确定不同管材的腐蚀状况,为储气库气井管柱的选材提供依据。

EXPERIMENTAL STUDY ON PIPE STRING CORROSION OF GAS-WELL IN HUTUBI GAS STORAGE OF XINJIANG OILFIELD

According to the requirements of CNPC about constructing underground gas storage,Xinjiang Oilfield Company started up the "reconstruction project of underground natural gas storage tank in Hutubi gas field".The main source of natural gas for the gas storage tank is the imported gas from Turkmenistan,In which carbon dioxide content is less than 2%,and maximum partial pressure of carbon dioxide is 0.68MPa.When producing,moisture content of Natural gas in wellhead and bottom hole is generally higher than the saturated water vapor content of natural gas under corresponding temperature and pressure,namely,below the dew point temperature.In such a case it will lead to more carbon dioxide corrosion.By analyzing we know the primary environment factors affecting carbon dioxide corrosion include carbon dioxide partial pressure,formation water salinity and chloride ion content,temperature,flow rate etc.Based on the above factors,we have designed a series of simulation experiment and evaluated carbon dioxide resistance performance of p110,3Cr110,general 13Cr110,HP1-13Cr110 and accessed to the pitting corrosion rates and average corrosion rates of different tubular.The experimental results provide theoretical foundation for selection of tubing materials for gas storage.