摘要
用长庆油田北三区原油、油田采出水、聚丙烯酰胺、甜菜碱表面活性剂配制了聚表二元驱采出液。采出液含水率为10%~90%，高浓度采出液含1000 mg/L聚合物、1667 mg/L表面活性剂，低浓度采出液含400 mg/L聚合物、600 mg/L表面活性剂。考察了含水率、聚合物浓度、表面活性剂浓度、剪切速率、温度等因素对聚表二元驱采出液流变性的影响。结果表明，10%~20%含水率高浓度采出液的乳状液类型为W/O型、25%以上含水率的采出液为O/W型，转相点在含水率20%~25%之间，而低浓度采出液的转相点在含水率25%~30%之间。温度升高，采出液黏度降低。当含水率较低时，随着聚合物表面活性剂浓度的降低，相同温度下的采出液（W/O型）黏度保持不变；当含水率较高时，随着含水率的增大和聚合物表面活性剂浓度的降低，相同温度下的采出液（O/W型）黏度逐渐降低。无论采出液为W/O型或O/W型，温度在反常点以下时，随着剪切速率的增大，采出液黏度降低，表现出剪切稀释性。
Abstract
The simulated produced fluid for polymer-surfactant flooding was prepared with oil from north third district in Changqing oilfield, oilfield produced water, polyacrylamide and betaine surfactant. The water ratio of produced fluid was range from 10% to 90%. High-concentration produced fluid contained 1000 mg/L polymer and 1667 mg/L surfactant, while low-concentration produced fluid contained 400 mg/L polymer and 600 mg/L surfactant. The effect of water ratio, concentration of polymer or surfactant, shear rate and temperature on the rheological property of simulated produced fluid was studied. The results showed that the emulsion type of high-concentration produced fluid was W/O when its water ratio was 10%—20%, and it turned to O/W when its water ratio was more than 25%. The phase transition point was between 20% and 25%. While the phase transition point of low-concentration produced fluid was between 25% and 30%. The viscosity of simulated produced fluid decreased with increasing temperature. When the water ratio was low, the viscosity of simulated produced fluid (W/O) remained constant with decreasing concentration of polymer-surfactant. When the water ratio was high, the viscosity of simulated produced fluid (O/W) decreased with increasing water ratio and decreasing concentration of polymer-surfactant at same temperature. Besides, whether the simulated produced fluid was W/O or O/W emulsion, the viscosity of simulated produced fluid decreased with increasing shear rate when temperature was below the abnormal point, which showed the property of shear-thinning.
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