Release:
2017, Vol. 3. №4About the authors:
Ramil F. Sharafutdinov, Dr. Sci. (Phys.-Math.), Professor, Department of Geophysics, Bashkir State University (Ufa); gframil@inbox.ruAbstract:
This article presents mathematical models of heat and mass transfer for calculating the volume content, phase velocity, temperature distribution in the trunk of a horizontal well. The authors consider the cases of a co-directional flow of water and oil, and in the presence of a counterflow of water, they assume the flow regime to be stratified. The calculation of the hydrodynamic problem takes into account the influence of gravity, interfacial friction and friction on the wall of the borehole. When calculating the temperature problem, the authors take into account convective heat transfer, interfacial heat transfer, and heat exchange with the borehole wall.
At present, mathematical models of co-directional two-phase and three-phase flows in a horizontal well have been thoroughly investigated, while thermohydrodynamic fields in the presence of a reverse flow are much less studied. Geophysical studies in horizontal wells show that, due to the complexity of the trajectory, very often there are wells in which the probability of backflows is very high. In connection with this, studies of the features of the formation of volumetric phase contents and the temperature distribution in the presence of countercurrent are becoming relevant.
The conditions for the emergence of the reverse flow were studied on the basis of an experiment: a boundary angle was determined, at which a countercurrent appeared for various oil and water rates. The results of calculation of thermohydrodynamic fields for real trajectories of horizontal wells show that the fraction of the backflow in the borehole section is small; due to this, the rate of the return flow can be significant. In this regard, the return flow has little effect on the temperature distribution, as it quickly takes the temperature of the ascending stream.
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