Measuring the surface roughness and surface energy of carbon steel pipes to understand hydrate-solid adhesion

Abstract

Gas hydrates are ice-like solids that occur when small, nonpolar gas molecules, such as methane or carbon dioxide, are trapped within a crystalline structure of water molecules under conditions of low temperature and high pressure [1]. These conditions often exist in subsea oil and gas pipelines and the aggregation/deposition of hydrates leads to blockages, which stop oil and natural gas transportation and poses subsequent environmental hazards. Not only do hydrate plugs create pressure build ups, but in some cases upon removal hydrate projectiles erupt from the pipe rupture. Solid surface characteristics, including the average surface roughness and surface energy, have been shown to impact the adhesive strength of the ice/solid interface in the literature. It is likely that such parameters also affect the adhesive strength of the hydrate/solid interface. By quantifying the surface roughness and surface energy of carbon steel pipes using contact profilometry measurements and goniometry, we can better understand the effects of these parameters on hydrate/solid adhesion and the potential impact on flow assurance.