化学驱采收率与三元复合驱体系黏度匹配关系研究

Study on Matching Relationship between Recovery and System Viscosity in ASP Combination Flooding

三元复合驱体系黏度是影响驱油效果的重要因素,为了研究其对化学驱采收率的影响,开展了不同黏度三元复合驱体系物理模拟驱油实验。驱油实验结果表明,在同一渗透率条件下,三元复合驱体系黏度过高或过低都不能达到最好的驱替效果,只有在某一体系黏度范围内,体系注入压力既保持了较高的升幅速度和升幅压力,又不会造成岩心堵塞,出现注入压力的突升突降,延长了三元复合驱体系在岩心中的作用时间,提高了三元复合驱体系波及体积能力和洗油效率,化学驱采收率才能达到最好效果,即化学驱采收率与三元复合驱体系黏度存在特定匹配关系。室内物理模拟驱油实验表明,岩心渗透率为0.5μm-2时,与该渗透率相匹配的体系黏度范围为20-30m Pa·s。大庆油田北二西矿场试验结果也说明,三元复合驱替体系在相匹配的黏度范围内,化学驱效果好,采收率达到29.02%。

System viscosity in the ASP combination flooding is an important factor of influencing the effect of oil displacement.In order to study its effect on the chemical flooding recovery,the physical simulation displacement experiments were made for the ASP system with different viscosity.The results show that the best displacement effect will achieve at certain range of viscosity instead of much high or much low viscosity un-der the condition of the same core permeability.The injection pressure of the system is high with high rise rate and stable for no core plugging.The action time of the ASP combination system on the cores will pro-long,and swept volume and displacement efficiency of the ASP combination system will be enhanced.And then the recovery of the chemical flooding is the highest,that is to say,there is matching relationship between chemical flooding recovery and ASP system viscosity.Laboratory physical simulation experiment shows that when core permeability is 0.5μm-2,the matching system viscosity is 20-30 m Pa·s.Field experiment in Beierxi of Daqing Oilfield shows that good effect was achieved at matching ASP system viscosity and the re-covery efficiency was up to 29.02%.