Yuri F. Makogon

Kinetics and Mechanisms of Gas Hydrate Formation and Dissociation with Inhibitors

Abstract: A common chemical used in petroleum industry for preventing hydrates is methanol. Other alcohols and glycols (thermodynamic inhibitors) can also be used to shift hydrate formation to lower temperatures and higher pressures. A new family of chemicals called kinetic inhibitors delays the formation of hydrates, but does not change the equilibrium formation conditions. We have constructed several new types of apparatus and present results on the kinetics of hydrate formation and dissociation in static and dynamic conditions with fresh water and different solutions of water, seawater, and with thermodynamic and kinetic inhibitors. We also present new morphological forms of hydrate crystal growth in different static and dynamic conditions.

TECHNICAL LIMITS FOR DEVELOPMENT OF NATURAL GAS HYDRATE DEPOSITS

In this work we have formulated the set criteria for cost-effective selection of technologies for industrial production of gas from a hydrate deposit, which rely on the properties of hydratebearing rock and the geologic properties of the gas hydrate deposit. For over forty years the world’s energy industry has been trying to effectively master vast unconventional resources of natural gas – the natural gas hydrates [1;3;4]. Specialists have accumulated during this period of time a great deal of knowledge about gas hydrates [8;10]. They established the conditions of hydrate formation in sedimentary rock and the conditions of formation and disappearance of gas hydrate deposits, and offered several classification methods for gas hydrate deposits. Specialists have proposed several methods to locate the gas hydrate accumulations on land and offshore and determined the probable areas where gas hydrate deposits may exist. More than 220 gas hydrate deposits were found to-date, and methods to calculate the amount of gas in a hydrate deposit were developed [1;12]. The principles of gas production from a hydrate deposit were formulated and real experience of commercial natural gas production from a hydrate deposit was gained. However, until now there were no set economic criteria for selection of effective technologies for industrial development of gas hydrate deposits. This results in periodic development of various models not applicable to specific geologic conditions.