极低剪切速率下聚丙烯酰胺溶液在毛细管中的流变特性 Ⅱ.毛细管尺寸和盐浓度对流变性能的影响

Capillary Rheological Properties of Polyacrylamide Solutions at Extremely Low Shear Rates Ⅱ.Effect of Capillary Size and Salt Concentration on Rheological Properties

在极低剪切速率下 ,用光学毛细管流变仪测定了聚丙烯酰胺 (PAM)溶液和含盐 PAM溶液通过不同内径 (2 5～ 1 5 0 μm)、不同长度 (4 0 .6～ 1 0 0 .1 mm)和不同内壁表面毛细管时的流变行为。结果表明 ,PAM溶液在微米级毛细管中流动时流变行为的改变是由于毛细管几何尺寸和内壁表面性质的影响 ,而含盐 PAM溶液流变行为的改变是由于 PAM溶液的带电性能。因此 ,多孔介质的孔道内径越大 ,长度越短对提高驱油效率越有利。减少 PAM溶液中的钠离子和设法增大

Using an optical capillary rheometer, the rheological behavior of polyacrylamide(PAM) solutions with different salt concentrations, flowing through capillaries of different diameter(25～ 150 μm ), lengths(40 6～100 1 mm) as well as with or without internal coated surface at extremely low shear rates have been studied. The results showed that the marked differences rheological behavior of PAM solutions flowing through capillaries of micron diameter are due to the geometrical dimension and nature of the internal wall surface of the capillaries, while the rheological differences occurved in salt containing PAM solution are due to the electrical property of the solution. Hence, greater internal diameter of the pores and channels and shorter lengths of the channels in the porous media of the oil field are favorable to the oil recovery. And decreasing concentration of sodium ions of PAM solutions could increase the interaction between PAM solutions and oil membrane also favorable to oil recovery.