Influence of Anodization Process on Improvement of Corrosion Resistance of Tubing from Aluminium Alloys

Abstract

Full functioning of wells in oil and gas fields is impossible without the use of tubing. Main function of tubing is transportation of gases and liquids produced in productive zone to well surface. In addition, tubing acts as a kind of insulator that protects the gas and liquid transported through them from the walls of the well, and also prevents the occurrence and development of corrosion, deposits of paraffin and asphaltene on casing pipes. The tubing pipe placed in the well is also necessary in order to ensure the carrying out of downhill and repair work, which is regularly necessary. Standard tubin g (tubing) as a result of technological difficulties does not undergo a strengthening operation. When manufacturing tubing and locks to them from alloyed steels, the main attention is paid to improving mechanical properties, which is achieved by thermal and chemical-thermal treatment. However, the practice of operating tubing shows that the introduction of these measures does not solve the issue of reliability, since threaded connections for the coupling and nipple remain vulnerable sections of tubing. Tubing (tubing) during its operation experiences significant loads and is in constant contact with aggressive media, which leads to serious requirements for their quality. The possibility of replacing its production from alloyed steels with aluminum alloys, for example, AlCuMg2 will facilitate the design by 2.5 times, prevent the tendency to stress corrosion cracking (SCC) in a hydrogen sulfide-containing medium and eliminate inhibitory protection. The main disadvantage of aluminum alloys is the tendency to pitting corrosion. It is possible to improve the protective properties of the passive film on aluminum alloys by anodizing.