萨尔图油田三类油层弱碱三元复合体系性质参数在不同注入阶段的变化规律

The Change Law of ASP Weak Alkali System Properties of Class Ⅲ Reservoir in Saertu Oilfield at Different Injection Stage

用相对分子质量为620×10~4、700×10~4(抗盐)、1400×10~4的聚合物(P_(620)、P_(700)、P_(1400))和石油磺酸盐表面活性剂、Na_2CO_3配制弱碱三元复合体系。通过分析萨尔图油田三类油层弱碱三元复合体系在岩心中流动时,不同注入阶段采出液黏度、界面张力、注入压力及阻力系数等参数,得到三元复合体系驱油性质在岩心中的变化规律。结果表明:随着复合体系注入量的增加,表观黏度不断增大;注入后续水时,随着注入量的增加表观黏度升高到最大值后降低,P_(620)、P_(700)和P_(1400)三元复合体系的最高黏度保留率分别为81.53%、17.22%和12.05%。随着驱替过程的进行,采出液界面张力先降低后升高,P_(700)、P_(620)界面张力最低值分别为6.59×10^(-2)和2.38×10^(-2)mN/m。随P_(700)、P_(620)、P_(1400)三元复合体系注入量的增加,注入压力先增大并分别达到最大值2.88、0.60、0.87MPa;注入后续水时,注入压力降低。P_(620)、P_(700)、P_(1400)弱碱三元复合体系的阻力系数分别为75.00、360.00、109.25,残余阻力系数分别为22.25、155.00、28.25。P_(620)弱碱三元复合体系在岩心中流动达到稳定时的注入量最小。

The alkali ASP system was composed of petroleum sulfonate surfactant, Na2CO3 and polymer P620, P700 and P1400 with relative molecular mass 620×10^4, 700×10^4 （salt resistant） and 1400×10^4. When the ASP flooding weak alkali system flowed in the core of class Ⅲ reservoir of Saertu oilfield, the apparent viscosity, interracial tension, coefficient of resistance and other parameters at different injecting stage were tested, and the change law of ASP flooding weak alkali system flooding properties in the core was obtained. The results showed that the apparent viscosity increased continuously with increasing composite system injection. When subsequent water was injected, the apparent viscosity increased first and then decreased with increasing water injection. The highest viscosity retention rate of P620, P700 and P1400 alkali ASP system was 81.53% , 17.22% and 12.05% , respectively. The interface tension of produced liquid decreased first and then increased during the conduct of displacement. The lowest interface tension of P700, P620 was 6.59 ×10^-2 and 2.38×10^-3 mN/m. With increasing injection rate of P700, P620 and P1400 ASP system, the injection pressure increased to the highest at 2.88, 0.60 and 0.87 MPa. When the follow-up water was injected, the injection pressure decreased. The resistance coefficient of P620, P700 and P1400 alkali ASP system was 75.00, 360.00 and 109.25, and the residual resistance factor of that was 22.25, 155.00 and 28.25, respectively. The injection rate of P620 alkali ASP system was the lowest when the flowing of ASP system in the core achieved stability.