龙虎泡低渗透油田聚表二元复合驱实验研究

针对龙虎泡低渗透油田水驱开发效果差、采收率低等特点,开展了聚合物和表面活性剂二元复合驱在低渗透油藏适应性的室内评价实验.注入性实验表明,相对分子量为2 200万的FP-3聚合物注入渗透率46.45×10-3μm2的岩心未发生堵塞,具有良好的注入选择性及封堵选择性.驱油实验表明,聚合物和表面活性剂可分别提高低渗透岩心驱油效率10%和20%,且表面活性剂容易注入,可降低注入压力.在聚合物和表面活性剂不同段塞组合实验中,两者分段塞注入的方式优于单独注入表面活性剂或将两者混合后注入的方式,其中先注聚合物后注入表面活性剂的段塞组合方式最好,可提高采收率17.74%.因此,对于非均质性较弱的低渗透油田,可采用聚表二元复合驱技术,先注入聚合物降低储层的非均质性,后注入表面活性剂启动低渗区的剩余油.

Experimental study on surfactant-polymer combination flooding in Longhupao low-permeability oilfield

Longhupao low-permeability oilfield is of the characteristics of bad water flooding result and low recovery factor.For this reason,the adaptability evaluation of surfactant-polymer combination flooding in the low-permeability reservoir was carried out by laboratory experiments.The injection performance experiment results of cores show that,polymer FP-3 with a relative molecular weight of 2 200 × 10 4 is of good injection selectivity and plugging selectivity,it can smoothly be injected into the core with the permeability of 46.45 × 10-3 μm 2 without producing plugging.The oil displacement experiments indicate that,polymer flooding and surfactant flooding could enhance the oil displacement efficiency by 10% and 20% respectively in low-permeability cores,and surfactant solution can be more easily injected and could decrease injection pressure.The experimental results of different slug modes composed of polymer and surfactant show that,the injection modes that polymer slug and surfactant slug are successively injected have better oil displacement performance than the modes that surfactant or polymer solution alone is injected and that the mixture solution of surfactant with polymer is injected.Among all injection modes,the mode that polymer plug is injected firstly and then the surfactant plug is injected is the best way,which can enhance the recovery ratio by 17.74%.Therefore,this mode should be adopted in the surfactant-polymer combination flooding of low-permeability reservoirs with less heterogeneity.