SIMULATION OF TWO-PHASE FLUID FLOW IN THE DIGITAL MODEL OF A PORE SPACE OF SANDSTONE AT DIFFERENT SURFACE TENSIONS

A study is made of the infl uence of surface tension on two-phase drainage fl ows in a porous medium. Computational fi ltration experiments are conducted in a three-dimensional digital microtomographic model of sandstone. To simulate two-phase fl ows, use is made of lattice Boltzmann equations; interfacial phenomena and wetting effects are described using the color-gradient-based method. Calculations are carried out at the same rate of injection of a nonwetting fl uid and at a ratio of the viscosities of nonwetting and wetting phases of 1:10. Results are obtained according to which growth in the interfacial tension contributes to the rise in the effi ciency of displacement of the wetting fl uid, which is recorded at the moment the injected phase breaks through, and to the decrease in the effi ciency after its breakthrough. It is established that distinctive features of fl ows with capillary fi ngering that arise at high surface tensions are the stepwise character of travel of the leading front and the growth of displacement channels in directions different from the hydrodynamic pressure difference. It is shown that interfacial tension is a parameter whose variation enables us to change the type of two-phase fl ow. Increase in the interfacial tension contributes to the transition of the fl ow with viscous fi ngering to a fl ow with capillary fi ngering. The effi ciency of displacement of the wetting fl uid in the transition crossover zone is the lowest.
   
Author:  T. R. Zakirov and M. G. Khramchenkov
Keywords:  two-phase fl ows, surface tension, digital core, simulation, lattice Boltzmann equations (method), capillary fi ngers
Page:  733