碱对复合体系启动中、低渗透层的影响及机理

Effect and mechanism of alkali on starting middle or low permeability layers of combination system.

利用渗透率变异系数为 0 .72的三层非均质加隔层物理模型和合注分采方式 ,研究了碱浓度变化对启动中、低渗透层的影响。结果表明 ,低碱复合体系因粘弹性高可以更多地采出中、低渗透层的残余油 ,而高碱体系因极大地降低了体系的粘弹性 ,启动中、低渗透层的能力最差 ;利用原子力显微镜“看到”碱的加入 ,使聚合物分子卷曲成较大尺寸的线团 ,致使复合体系的粘性、弹性降低 ,在HAAK -RS15

The effects of sodium hydroxide (NaOH) concentration on starting middle or low permeability layers have been studied by the experiments on heterogeneous physical models with three layers of different permeability and intermediate layers. The permeability variation factor of models is 0.72. The experimental project is in a way of commingled injection and separate production. The results show that the combination system with low alkali can displace more residual oil in middle or low permeability layers due to high viscoelasticity; while the combination system with high alkali has worst capacity to develop middle and low permeability layers for viscoelasticity is reduced greatly. The polymer molecules were curled over big size threads due to adding alkali that is saw in atomic power microscope. The threads result in the decreasing of viscosity and elasticity of the system. The rheological diagram of the system measured by HAAK-RS150 rheometer has also confirmed the results.