多元热流体不同组成介质耦合作用机理微观实验

Microscopic experiments on the coupling mechanisms of different media in multi-component thermal fluids

多元热流体吞吐是蒸汽吞吐的重要接替方式之一,而现有的研究尚不能清晰解释不同介质之间的耦合作用机理,难以为海上多元热流体开发提供有效措施。利用微观可视化模拟系统,通过非凝析气(CO_(2)、N_(2))和热水的不同组合驱油实验,研究微观条件下多相流动特点,揭示热水、CO_(2)和N_(2)三者之间两两相互影响的耦合作用机理,并定量分析耦合作用机理对波及系数、洗油效率和采收率的影响。研究结果表明:热水与N_(2)相互协同,提高波及系数,在驱替中期,热水加热稠油,降低流动阻力,N_(2)气泡变形膨胀,补充压力,在驱替后期,在主流道形成贾敏效应,驱替范围从主流道向边缘扩展;热水与CO_(2)相互协同,提高洗油效率,热水冲刷CO_(2)驱替过后的膜状剩余油,同时二者降低油气表面张力,将油气段塞式流动变为念珠式流动,消除附加表面张力,动用簇状剩余油,增大体系毛管数;CO_(2)和N_(2)之间相互竞争,N_(2)与CO_(2)分压,阻碍CO_(2)溶解,CO_(2)和N_(2)混合后,补能作用减弱;三种介质耦合作用时,采收率整体提高29%,协同作用效果比竞争作用效果更为显著。利用微观实验厘清多元热流体两两介质之间的耦合作用机理,为后期多元热流体开发稠油油藏提供理论指导。

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(CO_(2),N_(2))and hot water in oil displacement experiments.The coupling mechanisms between hot water,CO_(2),and N_(2) 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 N_(2) synergistically enhance the sweep efficiency.In the middle stage of displacement,hot water heats the heavy oil,reducing flow resistance,while N_(2) 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 CO_(2)work synergistically to enhance oil recovery efficiency.Hot water removes residual oil film post-CO_(2)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 CO_(2)and N_(2),with N_(2) partial pressure hindering CO_(2)dissolution.The energy supplement effect weakens after CO_(2)and N_(2) mixed.When the three compositions are coupled,the overall recovery factor increases by 29%,with synergies outweighing competition.The synergy between hot water and CO_(2)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.