Study On The Effect Of Heterogeneity Of CO₂ Foam Seepage Characteristics In Porous Media

The CO₂ foam technology has a great application background in increasing production and stable production of oil reservoir and underground storage of greenhouse gas.In this paper, we study the flow characteristics of CO₂ foam in porous media by experimental method.Visualization of dynamic seepage characteristics of CO₂ foam in porous media is studied by means of CT testing technique.Using CT scanning method to measure the variation of the saturation of each phase in the medium and using the multi point layout pressure sensor at the same time to obtain the synchronous data of the pressure distribution along the path.Deep analysis and Research on the macroscopic percolation characteristics of CO₂ foam in porous media by changing the system parameters.In order to lay a good foundation for the study on the effect of CO₂ foam fluid in the pore of the real core in the future and provides a large amount of data and theoretical support for the establishment of CO₂ foam fluid in porous media.Experimental results show that:（1）In homogeneous porous media: the model of porous media with different particle size sand obtained with similar porosity.CO₂ foam has a larger percolation pressure difference and smaller water saturation inlet effect in the porous medium with smaller average particle size thus it has a higher displacement efficiency.The foam stability is poor and the displacement efficiency is low when the concentration of the active agent is lower than the critical micelle concentration.When the concentration of the active agent is higher than that of the critical micelle the bubble stability is littleand the efficiency of the bubble liquid displacement is not large.With the increase of foam quality（the gas-liquid ratio increases） the displacement process shows a larger displacement pressure difference but it has little effect on the residual water saturation in the porous media.（2）In heterogeneous porous media: CO₂ foam has good sealing ability and good control performance.The foam in porous media flow in the cross section of the pressure difference.Bubble flows through high permeability channel by permeability from high to low flow along the bubble flow direction at each point in turn pressure change accordance with the rules of foam flow changes...