Adhesion force between cyclopentane hydrates and solid surface materials.

The mechanisms by which hydrates deposit in a petroleum production line are related to pipeline surface properties, fluid composition and properties, and water cut. In this work, adhesion forces between cyclopentane hydrates and solid surfaces were investigated as a function of the solid material, the presence of water and the presence of petroleum acids in the oil phase. The influence of dissolved water on hydrate adhesion forces was also investigated. The results show that the adhesion force between hydrates and solid surfaces was dependent on the surface material; solids with low surface free energy lead to the lowest adhesion forces. The adhesion force was strongly dependent on the presence of water in the system. When a water drop was deposited on the solid surface, the adhesion force between the hydrate and the solid surface was more than 10 times larger than hydrate-hydrate adhesion forces. The presence of a water-saturated oil phase also led to an increase in adhesion force between hydrate particles. Adhesion forces were highest when the solid surfaces are water-wet. Addition of petroleum acids to the oil phase drastically reduced adhesion forces.