Challenges and progress on ethane hydrates rheology under high pressure

One of the most common and critical inorganic deposition inside flowlines in the oil and gas industry is related to gas hydrates, which are crystalline water-based solids, formed in conditions of high pressure and low temperatures. In this work, experiments are carried out to analyze ethane gas hydrate formation in water-in-model oil emulsions, through a rheological analysis based on the variation of pressure, shear rate and water cut, using the vane and concentric cylinder geometries. High pressure time sweep tests were performed, and the results are presented through viscosity and pressure curves. The amount of water converted to hydrate was also estimated and related to the viscosity of the hydrate slurries formed. The results obtained show that the induction period was reduced by increasing the subcooling, water cut, and shear rate. Both geometries, vane and concentric cylinders, seem to be adequate to study hydrate formation and similar qualitative results were obtained, although the hydrate detectable and quantified region for the system employed were different.