Release:2017, Vol. 3. №2
About the author:Marat K. Khasanov, Cand. Sci. (Phys.-Math.), Associate Professor, Department of Applied Informatics and Programming, Sterlitamak Branch of Bashkir State University; email@example.com
A mathematical model of the injection of liquid hydrogen sulfide into a natural reservoir saturated with oil and water accompanied by the formation of H2S gas hydrate is presented. For the axisymmetric problem, self-similar solutions describing the temperature and pressure distribution in the reservoir are constructed and investigated for the thermodynamic consistency condition. It is established that depending on the mass flow rate of injection, both a complete transition of water and liquid hydrogen sulfide to the gas hydrate state on the frontal boundary is possible, as well as formation of an intermediate region in the formation in which water, hydrogen sulfide and its gas hydrate are in a state of phase equilibrium. Critical values of the mass flow rate of hydrogen sulfide injection corresponding to the incomplete transfer of water and hydrogen sulfide to the gas hydrate state are determined. On the plane of the parameters “mass flow rate — initial temperature” curves for different values of the initial water saturation are plotted separating different flow regimes of the process. It has been established that the regime with complete transition of water and hydrogen sulfide to the gas hydrate state on the frontal surface is realized at low values of mass flow, initial temperature and water saturation of the formation. It is shown that the formation of an intermediate region in which water, hydrogen sulfide and its gas hydrate are in a state of phase equilibrium, in formations with high initial temperature and initial water saturation, and also at high values of mass flow rate of hydrogen sulfide injection is due to the fact that under given conditions, the temperature at the hydrate formation boundary rises above the equilibrium decomposition temperature of H2S gas hydrate.