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.