Microscopic experiments on the coupling mechanisms of different media in multi-component thermal fluids
Multi-component thermal fluid injection is one of the important alternatives to steam huff-n-puff,but existing research cannot clearly explain the coupling mechanism between different media,making it difficult to provide effective advices for offshore multi-component thermal fluid injection development.In this study,a microscopic visualization simulation system was utilized to investigate the characteristics of multiphase flow under different combinations of non-condensable gases(CO2,N2)and hot water in oil displacement experiments.The coupling mechanisms between hot water,CO2,and N2 were revealed,and the impact of these mechanisms on sweep efficiency,oil displacement efficiency,and ultimate recovery factor were quantitatively analyzed.The results indicate that hot water and N2 synergistically enhance the sweep efficiency.In the middle stage of displacement,hot water heats the heavy oil,reducing flow resistance,while N2 bubbles deform and expand,adding displacing pressure.During the later stages of displacement,the Jamin effect manifests in the primary flow channel,extending the displacement range from the central channel to the periphery.Hot water and CO2 work synergistically to enhance oil recovery efficiency.Hot water removes residual oil film post-CO2 displacement,while both substances reduce the surface tension of oil and gas.This transformation from slug flow to bead flow eliminates additional surface tension,mobilizes cluster residual oil,and increase the capillary number.There is competition between CO2 and N2,with N2 partial pressure hindering CO2 dissolution.The energy supplement effect weakens after CO2 and N2 mixed.When the three compositions are coupled,the overall recovery factor increases by 29％,with synergies outweighing competition.The synergy between hot water and CO2 contributing more to the improvement of oil displacement efficiency and recovery factor.This study elucidates the coupling mechanisms between various media pairs in multi-component thermal fluid at a micro-scale level,providing theoretical guidance for the development of heavy oil reservoirs using multi-component thermal fluid injection.
万方数据
维普
