不同类型聚合物溶液对采油残余油的作用机理研究

通过实验测定了HPAM溶液和黄原胶溶液的流变性、在多孔介质中的流变性和残余阻力系数 ,计算了衰竭层效应 .用不同的浓度和注入速度进行了驱油实验 .提出聚合物分子缠结作用的增强不仅引起表观粘度增加或衰竭层厚度降低 ,而且使平行于油水界面的拉动残余油的力增加 ,从而使残余油饱和度降低 ,采收率提高 .随浓度增加 ,HPAM溶液的表观粘度和残余阻力系数增加 ,衰竭层厚度减小 ;黄原胶溶液的浓度高于缠结浓度时 ,衰竭层厚度和表观粘度变化不大 .注入速度增加时 ,两种聚合物溶液的衰竭层厚度均降低 ,HPAM溶液的残余阻力系数不变 ,粘弹性增加 ;而黄原胶溶液的残余阻力系数下降 .不同浓度和注入速度情况下两种聚合物溶液的驱油结果证实了文中提出的聚合物分子缠结作用和衰竭层效应对残余油的作用机理 .分子结构的不同是造成两种聚合物溶液在多孔介质中渗流规律和对残余油作用机理的差别的根本原因 .

VARIOUS TYPES OF POLYMER SOLUTION'S MECHANISM OF ACTION ON RESIDUAL OIL IN POROUS MEDIA

The rheological behavior of HPAM solutions and Xanthan solutions,their rheological behavior in porous media and residual resistance factors were measured experimentally,and the depleted layer thickness was calculated.Displacement experiments were proceeded with various concentrations and injecting speeds.It was expounded that the increase of apparent viscosity or the decrease of depleted layer thickness generated by the entanglement of polymer molecules can increase the force parallel to oil-water interface,which can pull more residual oil out and enhance oil recovery. With the concentration increase of HPAM solutions,the apparent viscosities increase and the depleted layer thickness decrease.When the concentration of Xanthan solutions was higher than the entanglement concentration,the depleted layer thickness and the apparent viscosities varied little.The increase of injecting speed can decrease the depleted layer thickness of both polymers,with residual resistance factors varying little and viscoelasticity increasing for HPAM solutions and residual resistance factors decreasing for Xanthan solutions.The flooding results with various concentrations and injecting speeds affirm the mechanism that the entanglement effect and the depleted layer effect of polymer molecules act on the residual oil.The difference in molecular structure of the two polymers used is the essential reason that results in their different flow behavior in porous media and different mechanism of action on residual oils.