Experimental study on reducing adhesion and friction forces between hydrate particle and pipe wall in marine hydrate production

During the exploitation of gas hydrates, the adhesion and deposition of hydrates on pipe walls are direct causes of hydrate plugging. Hydrate plugging experiments were conducted to identify a suitable inhibitor for oil-free systems. Based on the experimental device and method for measuring the hydrate-wall adhesion force, a measurement method and an approximate solution equation for the friction force were developed. The performance of the inhibitor on decreasing adhesion and friction between the cyclopentane hydrate and metal surface, as well as the underlying mechanisms, were analyzed. It was found that the addition of 0.5 % SLC, an amphoteric compound, prolonged the hydrate plugging from 49 min to at least 1000 min. Increases in ambient temperature, contact time, and hydrate hydrophilicity were found to enhance adhesion and friction forces, while a higher particle drag speed reduced friction. In addition, adhesion and friction forces were significantly higher in gas phase than in liquid cyclopentane. In these experiments, the presence of 0.5 % SLC significantly reduced adhesion and friction, with reductions of up to 77 % and 62 %, respectively. Therefore, hydrate adhesion and deposition on the pipe wall can be inhibited. The present study offers a novel method for mitigating hydrate plugging in marine hydrate production.