Environmentally Friendly Antiagglomerants: A Promising Solution for Gas Hydrate Plugging and Corrosion Risk Management in Oil and Gas Pipelines

Gas hydrates pose a serious flow assurance challenge due to their ability to form, agglomerate, and block subsea flowlines on relatively fast time scales, leading to the loss of production and potential safety and environmental risks. The hydrate management strategy based on antiagglomerant inhibitors has gained significant interest in recent years, particularly in long tiebacks, maturing fields, and deep-water projects. However, most of the antiagglomerants used are not environmentally friendly, and compatibility issues with corrosion inhibitors also arise during coinjection operations. Here, a new oleic acid derivative was synthesized and used to develop two formulations (OADs) as green multifunctional flow assurance chemicals to control hydrate agglomeration and corrosion risks inside oil and gas pipelines. The experimental results showed that the OADs effectively inhibited methane hydrate growth and formed a transportable hydrate slurry in a water-paraffin mixture. Moreover, 0.1 wt % OADs completely suppressed the corrosion process of carbon steel in a CO2- and H2S-saturated solution by a protection of 99.4%. Computational studies also revealed that the adsorption of OADs on the hydrate surface increased its hydrophobicity, preventing the hydrate and water droplets from aggregating or clumping together. Additionally, OADs decreased the binding energy of iron and corrosive species up to 99.5%, and corrosive ions were almost no longer in direct contact with iron. The binding energy between the inhibitor and iron indicated the formation of a stable protective film by the OAD molecules on the steel surface to protect it against acidic corrosion. These results contribute to show the potential of oleic acid as a valuable green source to develop dual-purpose antiagglomerant hydrate and corrosion inhibitors for hydrate-related safety management.