长春储气库低含CO_2条件下室内腐蚀实验研究

长春储气库是为满足长春、吉林等城市季节性调峰需求而即将建设的战略性工程,是东北管网的重要组成部分。气库的注入气CO2含量为2.91%,按照CO2分压标准,井口管柱处于严重腐蚀工况范围。为明确该CO2含量下井口管柱的腐蚀程度以及井口管柱材质的选择标准,针对长春储气库注入气低含CO2的实际情况,模拟地层水组分及井筒压力、温度条件,利用高温高压釜开展了AA、BB、CC、DD、EE、FF等6种井口材质及J55、N80、P110、3Cr、13Cr、13Cr等6种管柱材质的室内腐蚀评价实验。实验结果表明,低材质等级井口及管柱无法满足长春储气库2.91%CO2含量防腐蚀要求,该研究为长春储气库建设井口、管柱材质的选择提供了依据,同时也明确了低含CO2同样会对井口、管柱造成严重腐蚀。

Research on indoor anti-corrosion test under low CO2 condition in Changchun Gas Storage

Changchun Gas Storage is a strategic project to be constructed to meet the seasonal peak demands in Changchun, Jilin and other cities and also an important part of pipe network in northeast China. The carbon dioxide content of the input gas of gas storage is 2.91%. According to the differential pressure criterion of carbon dioxide, the well head pipe strings are seriously corroded. To define the corrosion degree of downhole pipe strings under such carbon dioxide content and selection criterion of materials of well head pipe strings, in the condition that the carbon dioxide content of the input gas of gas storage is low, the formation water composition, wellbore pressure and temperature are simulated to perform the indoor anticorrosion evaluation tests for AA, BB, CC, DD, EE, FF well head materials (six types) and J55, N80, P110, 3Cr, 13Cr, 13Cr pipe string materials (six types) by using the high temperature autoclave. The test result shows that well head and pipe string made of low-grade material cannot meet the anti-corrosion requirement of Changchun gas storage where the CO2 content is 2.91%. This research provides basis for the selection of materials of well head and pipe string for construction of Changchun Gas Storage, and also confirms that the low carbon dioxide content also will seriously corrode the well head and pipe string.