Numerical Investigations Of Multiphase Displacement Characteristics Of Foam Flow Process In Porous Media

In the petroleum industry,foam technology has been widely used to improve the oil production,and it has received extensive attention and research.Foam flooding can significantly improve the viscosity of gas phase,improve the oil-water mobility ratio,and further enhance the oil recovery.The seepage characteristics and seepage mechanism of foam fluid in porous media can be studied by numerical method,but the present foam model is not perfect.In this paper,a new stochastic bubble number model?Stochastic Population Balance model—SPB?is used to simulate the one-dimensional three-phase and two-dimensional two-phase of foam liquid in porous media displacement process.A one-dimensional three-phase numerical simulate is carried out on the foam three phase displacement process in a homogeneous oil/water/gas coexistence porous media of liquid.The effects of the maximum bubble density n_max and the foam generation rate K_g on foam displacement process is mainly discussed.The following conclusions are drawn that the greater the value of n_max lead to higher apparent viscosity of foam,and therefore the greater the pressure difference in the foam displacement process,the better the oil displacement effect.The larger the value of K_g,the number of foam can reach a balance in a short distance,so it has better displacement effect on the oil phase components,but shows little effect on total liquid phase displacement efficiency of the foam flooding process.Two-dimensional two-phase numerical investigations were carried out with special attentions on the inlet effect and outlet effect of foam flow process in a homogeneous porous media.In addition to the two original influence parameters of K_g and n?,the additional parameter K_fp is introduced to consider the effect of the relative permeability reduction of the foam phase.Parametric studies on K_g,n?,K_fp and inlet&outlet sizes D indicate that:The larger the value of K_g,the smaller the inlet effect of foam seepage process.While the larger the value of n_?,the greater the pressure difference,but it will not change the foam flow characteristics in the inlet and outlet regions.With lower K_fp values,the strong foam flooding behavior could be properly predicted with much higher pressure drop and lower water saturation.Numerical results at various inlet and outlet sizes clearly show the confined geometry effect on foam flow characteristics with smaller sizes corresponding to longer inlet and outlet regions.The numerical simulation results show that the inlet effect and outlet effect are obvious in the foam displacement process.The porous media have higher water saturation,lower pressure gradient and foam density at the restricted inlet area,while the restricted outlet leads to the increase of water saturation and the decreasing pressure gradient toward the outlet of porous medium.The results of numerical simulation are compared with those of corresponding experimental devices and CT measurements,and the consistency of the results verifies the correctness of the simulation calculation.The comparison results show that the numerical simulation can not only qualitatively reproduce the phenomena presented in the experiment,but also quantitatively reproduce the distribution of water phase saturation and the trend of pressure drop.Therefore,Stochastic Population Balance model can reasonably predict the inlet and outlet effects in the process of foam liquid flow in porous media.