One of the main corrosion problems faced by the oil and gas industry is HTHP (high temperature, high pressure) corrosion at both sour and sweet conditions. HTHP oil and gas fields are increasing for both onshore and offshore production. The dosage rate of HTHP corrosion inhibitor can be tremendously high depending on field conditions. Furthermore, it is a highly challenging project despite the high dosage rate of corrosion inhibitors.

This paper presents the results using HTHP Hastelloy RC autoclaves for the performance study of corrosion inhibitors with high H2S/high CO2 and low H2S/high CO2 environments in 80 % water cut. The testing temperature was 125 oC. API 5L X52 weight-loss coupons and an electrical resistance probe system were used for corrosion monitoring.

Specially formulated corrosion inhibitors for each HTHP sour condition showed that the target corrosion rate (less than 0.1 mm/year) with no pitting corrosion was achieved for both conditions. The results of the thermal stability test showed no differences in FTIR spectra and no loss of volume from the initial observation at 125 oC.