Close-to-reality sliding-corrosion test-rig for oilfield application

摘要

Sliding-corrosion phenomena play a crucial role in reducing the lifetime of tubings in oil production industry. The aim of the present work is to develop and apply a close-to-reality test rig to describe the tribological performance of low-alloyed Carbon-steel (C-steel) under sliding-corrosion conditions in O_2-free environment. The proposed test rig is highly relevant for oil production industry and has been designed at the Austrian Competence Center for Tribology (AC~2T). The benefit of this equipment is that it allows setting the CO_2 atmosphere at a certain partial pressure while simultaneously varying the pH-value, Cl~- ion concentration, and temperature of the electrolyte solution. Pure corrosion phenomena are investigated within a designed coupon box where conditions of steam, electrolyte injection, static and dynamic flow are controlled. In addition to the corrosive environment, a tribological reciprocating sliding contact is implemented between tubing segments and coupling samples. Within this study, commercially available low-alloyed C-steel was selected as base material for the tubing which was tribologically stressed under reciprocating sliding contact against spray metal coated couplings. The results show a high influence of the steel microstructure on the performance of low-alloyed C-steel tubings under sliding-corrosion. Additionally, the dominant damage mechanisms that are observed in real field applications could be successfully reproduced by experimental simulation using this novel designed close-to-reality test rig.