Abstract
Sour gas pipelines are often operated under the conditions that are conducive to corrosion and gas hydrate formation. In order to protect the integrity of the pipelines and to prevent potential solid hydrate blockages, the continuous application of corrosion inhibitors (CI) and kinetic hydrate inhibitors (KHI) is an attractive chemical solution to minimize the risk. However, CI and KHI are not always compatible with each other when co-injected. This study confirms that the presence of CI can significantly decrease the performance of KHI. The adverse effect is attributed to the interference between these two types of molecules. The attempt to overcome the negative effect of CI by increasing the KHI dosages worked only for a very limited number of CI molecules. It is also not an economical approach as KHI is usually more costly and its effective dosage is usually higher than CI. The need to have a fully compatible CI/KHI package has prompted an extensive research program that resulted in the successful development of a number of new CI formulations. These new formulations not only achieved outstanding performance in the laboratory tests under sour conditions but also did not interfere with KHI to adversely lower its performance when present together. Some of these new CI formulations demonstrated exceptional film persistency with their performance rivaling the benchmarks and thus can be considered for batch applications. The continuous injection of compatible CI/KHI packages along with periodic batch treatments using KHI-compatible CI is an effective solution to minimize the risk of corrosion and hydrate problems in sour gas pipelines.
