The oil and gas industry is moving into increasingly deeper wells and harsh environments (e.g., high temperature, high acid gas partial pressure, high chloride concentration). It has been exposed to extreme pressure and temperature, and these conditions have become one of the significant challenges to corrosion control. Due to these reasons, the selection of a corrosion inhibitor plays an increasingly important role in oil and gas production. It is well-known that corrosion inhibitor injection rates for carbon steel downhole production tubing and pipeline are up to 1,000 ppm under high temperature, high pressure (HTHP) conditions.
This paper presents the testing results for the performance study of a corrosion inhibitor with high H2S/CO2 conditions using the HTHP Hastelloy RC autoclave. The temperatures of the two field case studies were at 144 °C and 170 °C. API 5L X65 weight-loss coupons were used in the test. Some important standard tests (e.g., thermal stability) based on ASTM G170 were also presented.
The test results showed that the HTHP corrosion inhibitor showed the target corrosion rate (less than 0.075 mm/yr) with no pitting corrosion. The thermal stability test presented that no differences in FTIR spectra were noticed after 14 days at 170 °C, and the sample appeared unchanged by the thermal exposure.
Nowadays, oil and gas fields containing a high concentration of CO2 and H2S at high temperatures are being operated in many areas. Here, internal corrosion control under these conditions has become one of the significant challenges in oil and gas production wells and a major cause of severe corrosion–related material failure in the industry.
Internal corrosion of the pipelines turns out to be a critical threat to the initial stage of production1. It was reported that more than 9000 failures occurred due to internal corrosion were reported from 1990 to 20122. The oil and gas companies in the USA disburse 1.052 billion dollars annually to prevent internal corrosion1.
