三元复合体系黏度对各组分色谱分离的影响

摘要

碱、表面活性剂和聚合物三种物质化学吸附和机械捕集等性质的差异导致它们在多孔介质内运移过程中滞留量的不同,即发生色谱分离现象,这将对碱与表面活性剂间的协同效应产生不利影响.近年来,为了扩大三元复合驱的波及体积,大庆油田开展了高聚合物浓度三元复合驱矿场试验.针对理论研究和矿场应用实际需求,采用仪器分析和物理模拟方法,开展了三元复合体系黏度及段塞组合方式对色谱分离影响实验研究.结果表明,与“低聚合物浓度和整体段塞”三元复合驱相比较,“高聚合物浓度和多段塞组合”三元复合驱注入压力增幅较大,扩大波及体积效果较好,采收率增幅较大；另一方面,由于碱、表面活性剂和聚合物存多孔介质内滞留水平存在差异,注入压力愈高,波及体积愈大,碱和表面活性剂滞留量差异愈大,色谱分离现象愈严重.由此可见,尽管碱与表面活性剂间发生色谱分离会削弱复合驱的洗油效率,但这是否会影响采收率还取决于波及体积与洗油效率各自对采收率贡献的相对大小.%Because of the quality differences in chemical adsorption,mechanical trapping and so on of alkali,surfactant and polymer,the different hold-ups are resulted in for these components migrating in the porous media,that is the phenominon-chromatographic separation,thus the adverse impact on the synergistic effect between alkali and surfactant will happen.In recent years,in order to expand the swept volume of ASP combined flooding,the pilot tests with high polymer concentration have been waged in Daqing Oilfield.In light of the theoretical researches and actual field needs,a series of experiment were carried out to study the effects of both alkali/surfactant/polymer (ASP) system viscosity and slug combination mode on the chromatographic separation with the help of the methods of instrumental analysis and physical modeling.The results indicated comparing with “Low polymer concentration and unified slug”,although the ASP flooding with higher polymer concentration and multi-slug combination mode faced with much higher injection pressure increment,pretty wider swept volume and much higher oil recovery can be obtained.On the other hand,due to the difference of the hold-up levels in the porous media for the three chemicals,the higher the injection pressure,the wider the swept volume,the sharper contrasts for these three components,and the more serious the above phenominon will be.Therefore,although the chromatographic separation happened between alkali and surfactant can lower ASP displacement efficiency,whether the oil recovery will be weakened or not is still dependent on the relative sizes of the contributions of the swept volume and displacement efficiency to the oil recovery.