Study On Micro Distribution Of Residual Oil In Sandstone

To illustrate the effect of pore structure on fuild distribution in the porous media,we combined laboratory experiments with flowing simulation to study the micro-distribution of residual oil.This study has significance to improve reseach of EOR technology in pore-scale and further enhance oil recovery in high water cut stage of oil field.Based on digital core and pore network model method,four sandstone samples with different permeability were used to carry out indoor micro displacement experiments and fuild simulation,which can achieve the unification of the pore structure characteristics and distribution law of fuild.Firstly,digital core and pore network model of the samples with different pore structures were reconstructed by CT scanner.Secondly,based on Euclidean distance method and pore network model,pore structure characteristics of the samples like pore radius,throat radius,Coordination number,etc.were analyzed.Thirdly,Based on cluster-size distribution of oil segmented from the tomography images and classification using shape factor and euler number,transformation of oil distribution pattern in different injection stage has been studied for the samples with different pore structures,which demostrated distinctly different evolution behavior of oil cluster.Fourthly,the effect of pore structure and wettability on micro-distribution of residual oil were analyzed,based on the flowing simulation results using pore network model of the samples.Finally,combined the experiment results and simulation results,reasonable suggestions for every type of pore structure can be presented to adjust the production measures in high water cut stage of oil field.As we formed systematic micro-displacement experimental method and quantitative characterization method to study three dimensional micro distrubution of resudual oil,this study improves our ability to further enhance oil recovery.