A Rheological Study of Natural Gas Hydrates

As the demand for energy increases, the oil and gas industry is expanding to extreme environments to meet it. However, with such expansion come many elements that could impede the flow of oil and gas from the reservoir to the point of production safely and profitably. Gas hydrates formed during production are one of the major issues in flow assurance. Gas hydrates are ice-like structures that can form, agglomerate, and accumulate in flowlines under high-pressure and low-temperature conditions. In addition to flow assurance concerns, there is an interest in hydrates for use in energy storage, CO2 capture, and chemical separation. For these reasons, there is real value in understanding their behavior and characteristics that affect their onset and physical properties. This work utilizes a high-pressure rheometer to provide a rheological analysis of natural gas hydrates. Different temperatures and pressures are employed to encompass a variety of field cases better and to view how changing the driving forces of hydrate formation affects viscosity. Temperature and pressure are shown to have a notable impact on the rheological behavior of hydrates, with low temperatures and high pressures being favorable for formation, leading to significant increases in viscosity. Temperature, however, is much more notable having an impact that is 2 orders of magnitude higher than the impact from pressure. This data can help improve understanding of natural gas hydrates and their effect on flow assurance.