Release:
2017, Vol. 3. №2About the authors:
Ramil F. Sharafutdinov, Dr. Sci. (Phys.-Math.), Professor, Department of Geophysics, Bashkir State University (Ufa); gframil@inbox.ruAbstract:
The study of multiphase flows in wells is followed by works of many scientists, both in Russian and abroad. Despite this, the issue of forming a temperature field in the “well — formation” system in conditions of oil degassing remains not fully researched. To date, the interpretation of thermal studies of wells is made at a qualitative level; quantitative estimates require the consideration of the influence of a large number of parameters. In oil production practice and during geophysical studies, the pressure in the well may drop below the gas saturation pressure of the gas. Under these conditions, oil degasses. Therefore, it is urgent to develop a mathematical model of two-phase oil and gas filtration and to study the main features of the temperature field in the “well — formation” system in conditions of oil degassing.
The numerical solution of the system of equations describing non-stationary motion of carbonated oil in the “well — formation” system is considered in the article. The aim of the research is to determine the zone of the beginning of degassing by the temperature distribution in the wellbore.
The solution of the system of differential energy equations, mass conservation is made by the control volume method.
The study consists in modeling two-phase oil and gas filtration in the “well — formation” system at a different value of the gas saturation pressure of gas. It was shown that with increasing saturation pressure, the degassing process of oil tends to the well sump and penetrates into the formation.
As it is known, the pressure of oil saturation with gas is determined in laboratory conditions on the basis of oil samples obtained from a well. However, there are often cases of lack of these data on the field. Therefore, the use of correlation dependencies of saturation pressure is often a necessary step to ensure the accuracy of numerical calculations. In addition, studies have shown that the saturation pressure can be estimated from the data of pressure and temperature changes.
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