Study on the Distribution of Corrosion Inhibitor in the Natural Gas Gathering Pipeline

Abstract

Acid gases such as H₂S, CO₂, SO₂ carried in natural gas will form acid liquid with water during transportation, which is prone to serious corrosion problems such as perforation and leakage. Corrosion inhibitors are often used as one of the main anti-corrosion processes. With regard to the serious internal corrosion of the gas gathering pipeline in a well in Moxi, based on the actual operational conditions, this paper establishes a CFD model to study the distribution of corrosion inhibitors. The simulation results show that: ① the larger the pipeline angle and the faster the injection velocity, the better the distribution of the inhibitor particles in the pipe. Although the injection rate will affect the inhibitor concentration in the pipe, the regularity remains unchanged; ② when the injection velocity increases, the inhibitor becomes better distributed and can protect the longer range of the pipeline; ③ the corrosion inhibitor at the top of the pipe will settle and attach to the wall due to the gravity, and the fluid would rise to the middle and upper part of the pipeline due to the influence of secondary flow after passing through the elbow, causing the inhibitor concentration to increase rapidly.