普通稠油降粘剂驱物理模拟和数值模拟

为实现普通稠油热采转化学驱，通过物理模拟实验和数值模拟方法研究了降粘剂驱提高稠油采收率的驱替机理。首先通过实验评价了降粘剂的性能参数，然后通过岩心驱替实验开展了降粘剂驱注入特征和驱油效果研究，通过微观可视化实验研究了降粘剂驱提高采收率的机理，最后对物理模拟实验结果进行了数值模拟和历史拟合。研究结果表明，稠油降粘剂驱过程中能够形成稳定的水包油乳状液，稠油驱替过程可划分三个阶段：启动压力突破阶段，压力快速下降阶段，压力低位运行阶段；降粘剂驱可以降低稠油启动压力梯度，减小驱替压力，实施降粘剂驱后采收率提高了12.4%，总采收率达到46.6%；降粘剂提高采收率的主要机理是降低原油粘度，减少残余油饱和度；采用非线性混合规则拟合实验结果，表征了原油粘度随降粘剂浓度的变化规律，可以应用于数值模拟计算，模拟结果和实验值拟合得较好；先导试验表明该技术能够降低水井注入压力，降水增油效果显著，试验区内油井全面见效。

Physical Experiments and Numerical Simulations of Viscosity Reducer Flooding for Ordinary Heavy Oil

In order to realize the conversion from thermal recovery technologies to chemical flooding for ordinary heavy oil, the EOR mechanism of viscosity reducer flooding to improve heavy oil recovery was studied by physical experiment and numerical simulation methods. Firstly, the performance of viscosity reducer was evaluated, then the injection characteristics and oil displacement performance were studied through core oil displacement experiments, the mechanism of oil recovery improvement by viscosity reducer was studied through microscopic visualization experiments, and finally the history match between indoor physical experiment results and numerical simulation were conducted. The results show that the process of viscous oil viscosity reducer flooding can form a stable oil-in-water emulsion, the process of water flooding can be divided into three stages, starting pressure breakthrough stage, pressure rapid decline stage, low pressure operation stage. Viscosity reducer flooding can reduce the starting pressure gradient, reduce the displacement pressure, the oil recovery factor was increased by 12.4% using viscosity reducer flooding, and the total recovery reached 46.6%. The main mechanism of improving oil recovery by viscosity reducer is to reduce crude oil viscosity and residual oil satu ration. By using the nonlinear mixing rule, the variation rule of crude oil viscosity with viscosity reducer concentration is obtained, which can be applied to numerical simulation directly. The pilot test shows that the water cut was decreased and oil production was increased, which also reduces the injection pressure of the well and makes the wells effective.