Application of Wet Gas Internal Corrosion Direct Assessment Methology for Pipelines Based on Grey Correlation Analysis Method

In order to grasp the internal corrosion of submarine pipelines that cannot be tested internally, taking a wet gas pipeline in the South China Sea as an example, the actual flow state of the submarine pipeline was simulated by multiphase flow software, and the NORSOK model was used to calculate the corrosion rate of the submarine pipeline. Wet gas internal corrosion direct assessment methology (WG-ICDA) for pipelines was used to predict the high risk position of pipeline corrosion, and grey correlation analysis method was introduced to judge the main influencing factors of submarine pipeline internal corrosion. The results showled that the submarine pipeline was mildly corroded. The stand pipe section, low-lying pipe section and pipe section within the first 110 km of the pipeline were high-risk locations for corrosion. The re-evaluation time interval was determined to be 8 a. The results of multiphase flow simulation and corrosion coupon test were basically consistent. It was proved that WG-ICDA had certain reliability. Pressure, CO₂ partial pressure, temperature and liquid film velocity were the main factors affecting the internal corrosion of submarine pipelines.