Experimental Study on the Growth of Methane Hydrate by Amino Acid Solution in the Oil–Water System

The impact of different surfactants on hydrate formation varies, and exploring hydrate growth characteristics is crucial for advancing the industrial application of oil and gas transportation. This study employed a microscope to investigate the hydrate formation rate and the morphology and formation process of the hydrate along the wall. It also visually demonstrated the hydrate formation process on the wall within an oil-water system and the migration patterns of different liquid phases inside the hydrate, leading to the characteristic of various wall hydrate growth modes. The results indicated that the addition of three amino acids, methionine, tryptophan, and leucine, could promote hydrate formation. The presence of amino acids reduces gas-liquid interfacial tension and accelerates gas molecule dissolution, thereby facilitating hydrate nucleation and further growth. In oil/water systems with different oil/water ratios, the way hydrates formed on the wall interact with water molecules varies, resulting in differences in formation rates and morphological characteristics. When hydrates form on the wall, the liquid phase migrates to different locations under the action of capillary forces to facilitate further hydrate formation. Notably, when two initially separated hydrate masses come into contact during growth, a porous bridge forms at the contact interface. Subsequently, excess water molecules are transported to surrounding areas, accelerating the hydrate formation. These findings provide a theoretical foundation for understanding hydrate formation in oil-water systems with amino acid solutions and offer valuable insights into the industrial application of hydrate transport technology.