[15]P3 Two Phase-flow Induced Corrosion in Natural Gas Wells

[15]P3 Two Phase-flow Induced Corrosion in Natural Gas Wells

A corrosion study of the influence of a mist flow (two phases) on materials commonly used in natural gas wells was conducted. The study was carried out in a way to simulate conditions normally found in natural gas wells in which a mist flow of natural gas and hydrocarbons are present. In other words, a new scheme of flowing rig has been built for such a study. Different experimental parameters such as temperature, gas velocity, fluid flux rate, and pressure of the gas were controlled and regularly monitored during experiments. Furthermore, the corrosion rate of various materials was determined by the weight loss method. The results show that L80 (low carbon) steel has higher corrosion rate than 38Mn6 ‘J66’ (low alloying-high strength) steel at pressures of 5 and 10 bar. On the contrary, AF22-100 steel (stainless steel) and MW2832 steel (nickel based alloy) show no sign of corrosion at all at both pressures of 5 and 10 bar in similar experimental conditions of L80 steel and 38Mn6 ‘566’ steel.The L80 and 38Mn6 ‘566’ steels are found susceptible to corrosion in the mist flow condition, simulating environments which normally exist in natural gas wells. In contrast, AF22-100 and MW2832 steels are found to have an excellent corrosion resistance in the same conditions.The corrosion rate of the 38Mn6 ‘J66’ steel is found to be less than that of the L80 steel. This is due to the small addition of Mo and Ni into the 38Mn6 ‘566’ steel which enhanced the corrosion resistance of the alloy compared to the L80 steel.An increase of CO, pressure increased the corrosion rate of the 38Mn6 ‘566’ steel but not the L80 steel.The addition of a high content of corrosion resistance-alloying elements such as Cr and Ni into the AF22-100 and MW2832 steels has given these steels an excellent performance in both conducted tests.A comparison among the investigated alloys indicates the following:Few conducted studies have been reported on evaluating the corrosion behavior of materials in extremely mist flow conditions, simulating environments normally found in natural gas wells in laboratories.'*2 Indeed it is a challenge to investigate the corrosion behavior of materials in dangerous environments especially in the present of toxic gases, i.e., H, S, high flux rate, high temperature, and high pressure. However, the benefits of undertaking the challenge are essential for many economical reasons in oil and gas industries.The objective of the present investigation was to evaluate the corrosion behavior of the L80, 38Mn6 ‘J66’, AF22-100, MW2832 steels under a mist-flow condition, simulating conditions normally existing in natural gas wells.EXPERIMENTAL WORK Corrosion specimens were fabricated from the

WPC-29274

1997

Habib, K.

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