Novel Biosurfactants for Effective Inhibition of Gas Hydrate Agglomeration and Corrosion in Offshore Oil and Gas Pipelines

Gas hydrate and corrosion inhibitors are widely used to ensure a successful and economic hydrocarbon stream flow inside oil and gas pipelines. However, compatibility problems are observed during their co-injection into the flowlines as they have different molecular chemistry. Using anti-agglomerant hydrate inhibitors is an effective method to control the gas hydrate plugging risk in deep-water hydrocarbon flow lines or throughout drilling operations. Here, oleic acid was used to develop the first class of biosurfactants as anti-agglomerant and corrosion inhibitors using click chemistry for flow assurance applications. The results of high-pressure autoclave showed that both bio-based anti-agglomerants (BAAs) significantly inhibited gas hydrate agglomeration, and the value of torque remained constant during the hydrate formation process. The hydrate particles were effectively dispersed in liquid paraffin in the presence of 1 wt % of BAA1 or BAA2. In addition, molecular dynamic simulation revealed that the headgroup of BAA1 was adsorbed on the hydrate surface, and its alkyl chain dispersed the hydrate formed in the hydrocarbon phase as a slurry. According to electrochemical measurements, both BAAs were highly efficient inhibitors for the prevention of mild steel corrosion in saturated H2S and CO2-simulated oilfield water. BAA1 and BAA2 completely protected the steel in the corrosive medium by 99 and 98.8%, respectively, at 0.1 wt %. Moreover, the adsorption of BAA1 molecules on the steel surface was both physically and chemically in a direction that was almost parallel to the surface. Such adsorption provides the maximum surface coverage against corrosion. These findings suggest that oleic acid can be used as a potential starting material to develop eco-friendly inhibitors for flow assurance in oil and gas pipelines.

Automated summary

Gas hydrate and corrosion inhibitors are commonly used in oil and gas pipelines to ensure smooth flow, but compatibility issues arise when they are co-injected. Using anti-agglomerant hydrate inhibitors is an effective method to control gas hydrate plugging in deep-water hydrocarbon flow lines or drilling operations.