强碱三元复合驱钙、硅垢沉积模型及结垢预测

Ca/Si scale sedimentary model in the strong-base ASP flooding block and scaling prediction

以Oddo-Tomson饱和指数法和硅钼黄法测定低聚硅为基础,研究了大庆油田强碱三元复合驱区块的温度、压力、pH值和离子强度等因素对CaCO_3垢和硅垢沉积的影响规律;采用多项式函数和MATLAB中exponention函数对钙、硅混合垢沉积数据进行拟合,建立了钙、硅混合垢沉积预测方程,并结合成垢离子数据、pH值等,建立了大庆油田三元复合驱钙、硅混合垢各阶段结垢的量化预测方法。针对不同油藏区块,通过水驱空白CaCO_3饱和指数值和低聚硅理论饱和值对三元复合驱混合垢预测模型进行修正,可以提高结垢预测准确率;对大庆油田喇北东区33口井和南五区39口井进行结垢预测验证,钙、硅混合垢结垢预测的准确率分别为92.8%和89.6%。

Based on the Oddo-Tomson saturation index method and the silicon molybdenum yellow method for determining oligomericsilicon, the influencing law of temperature, pressure,pH , ionic strength and other factors on Ca/Si scale sedimentation in thestrong-base alkaline-surfactant-polymer （ASP） flooding block of Daqing Oilfield is studied. The exponention function in MATLABand polynomial function are used to fit the sedimentary data of Ca/Si scale, eo as to establish the prediction equation of Ca/Si scale.In combination with scale ion data and pH value, the quantitative prediction method is created for different scaling stages of Ca/Si usingASP flooding in Daqing oilfield. Aiming at different oilfield blocks, the saturation index of water-flooding blank calcium carbonateand the theoretical saturation index of oligomeric silicon were used to modify the prediction model of Ca/Si scale in ASP flooding,so as to improve the accuracy of scaling prediction. The scaling predictions of 33 wells at La Beidong block and 39 wells at Nanwublock in Daqing oilfield are validated, and the accuracy of Ca/Si scaling prediction is 92. 8% and 89. 6% , respectively.