Corrosivity data for halide and formate well brines that have been acidifies as a concequence of influx of large amounts of acid gas has been requested.
The well materials C-steel, standard 13%Cr steel and Super 13%Cr steel were corrosion tested in potassium formate and CaBr2 brines acidified with CO2 gas, simulating a well situation with influx of acid gas. The acidification resulted in an initial accelerated corrosion of C-steel in both solutions, reduced to low levels by time due to formation of a protective iron-carbonate layer. Both C-steel and standard 13%Cr steel were attacked by severe localised corrosion in the bromide brine, whereas only limited general corrosion was developed in the formate brine. Super 13%Cr was uncorroded in both brines.