Keyword: «hydrate formation»

In work the theoretical model of process migration metane bubbles in water is offered under conditions of formation hydrate. Feature of evolution fields of temperatures, migration speeds, and also distribution of radius and the volume maintenance of systems gas-hydrate bubbles is studied. It is shown that at the fixed mass consumption of gas from a bottom of a reservoir the quasistationary picture in a wave mode like "step" for parameters of emerging gaseous-hydrate disperse system is established. It is established that the speed of emersion of gas-hydrate inclusions decreases more than three times owing to increase in their weight because of hydrate formation.

The inverse problem of determining the gas mass flow by measurements of wellhead pressure with a cross-section of the well varying in length and time is solved by mathematical modeling methods, which makes it possible to identify signs of hydrate formation in it, consisting in different dynamics of pressure and temperature distribution. The results of a computational experiment were compared for two wells of the Otradninsky gas condensate field, the exploitation of which indicates that the most likely cause of complications is the gas hydrates formation both in the bottom-hole zone and in the borehole and their plumes. The influence of geocryological conditions and pressure drop in wells on the dynamics of hydrate plug formation and on the total amount of produced gas is shown.

In a computational experiment, the analysis of the influence of taking into account the dependence of the equilibrium conditions of hydrate formation on the reservoir waters mineralization type on the formation of hydrates in wells during natural gas production was carried out. The study was carried out within the framework of the model of joint operation of the system "reservoir – well" during its thermal interaction with surrounding rocks. The dynamics of changes in temperature, pressure, moisture content of gas and flow section in wells are predicted. It was found that when taking into account the mineralization of reservoir waters, the time interval from the moment of starting wells to the their complete blockage with hydrates increases.

The kinetics and thermodynamics of the growth and decomposition of R134a freon hydrates have been studied. It has been established that synthesis from liquid freon and snow at atmospheric pressure is effective at temperatures below -26°C, and the process is limited by diffusion. The activation energy of hydrate decomposition was 38.7 kJ/mol, and the gas content was 40 ml/g of water. The thermodynamic parameters were determined by the DSC method and the effect of the system's background and the inhibitory effect of a eutectic solution of CaCl₂ (~25°C) on hydrate formation was shown. The process is technologically controllable and promising for use.