Cause Analysis of L80 Tubing Corrosion Perforation

L80 tubing corrosion perforation occurred in a certain well of Ecuador. In order to know the cause of tubing perforation, the macro morphology of the failed tubing，material chemical composition and metallographic microstructure were analyzed, and the micro morphology of corrosion and corrosion products were observed by SEM. Analysis results show that the tubing corrosion has the characteristic of CO2 corrosion. The CO2 dissolved in the water of the crude in the well formed carbonic acid which caused corrosion. The failed tubing was at the well section in which the temperature range caused reletively great CO2 corrosion rate, and the existence of chloride in the crude also catalytically promoted the corrosion.