Conjoint Action of CO₂ Corrosion and Reciprocating Sliding Wear on Plain Carbon Steel Part I — Effect of Contact Pressure and Amine Inhibitor

The conjoint action of CO2 corrosion and reciprocating sliding wear on sucker rod couplings and tubing constitutes a serious problem in directionally drilled oil wells. In this study, sliding wear corrosion tests were carried out in a 3% NaCl aqueous solution saturated with CO2 gas in the absence or in the presence of an amine corrosion inhibitor. Weight loss measurements were made at various contact pressures. Scanning electron microscopy was used to study the surface features of specimens tested under various loading conditions with or without inhibitor addition. The weight loss measurements showed that the samples representing the sucker rod couplings, which are subjected to continuous sliding contact, lost more metal than those representing the tubing at all times in the presence and in the absence of the corrosion inhibitor. The rate of metal loss increased with an increase in contact pressure. Inhibitor additions resulted in lower metal loss rates for all specimens.