三元复合驱替液取样器的结构与流场模拟研究

在三元复合驱技术中,黏度是驱替液重要的技术指标之一,在配注过程中需要取样检测。驱替液在取样过程中受到一定程度的剪切后会发生降解,造成黏度下降,不能真实反映配注系统中驱替液的黏度情况,为此设计一种低剪切取样器,通过螺纹配合控制活塞缓慢移动,降低驱替液在取样时受到的剪切作用。对取样器内部流场进行模拟分析,发现取样腔内的样品黏度几乎不受剪切影响,这是因为取样腔内径较大,且活塞移动速度慢,流动剪切极小;而出入口的细管内样品黏度略低于取样腔内样品黏度,这是因为细管直径较小,流动剪切比取样腔内大,但还不足以破坏驱替液的高分子链缠结结构,不会造成样品黏度的不可逆损失。该取样器结构在取样过程中能最大程度保持样品黏度,便于准确测试流程中驱替液的真实黏度。

Simulation Study on Structure and Flow Field of ASP Flooding Displacing Fluid Sampler

In the ASP flooding technology, viscosity is one of the important technical indicators of displacement fluid, which needs to be sampled and tested during the injection and allocation process.The displacement fluid will degrade after being sheared to some extent during the sampling process,resulting in a decrease in viscosity,and then it does not truly reflect the viscosity of the displacement fluid in injection and allocation system. Therefore, a low-shear sampler is designed, which uses a threaded fit to control the piston slowly moving and reduce the shearing effect of displacement fluid during sampling. The simulation analysis of the internal flow field of the sampler reveals that the sample viscosity in the sampling chamber is almost unaffected by shearing. This is because the inner diameter of the sampling chamber is large,and the piston moves slowly,and the flow shear is extremely small. At the inlet and outlet of the thin tube, the viscosity of the sample is slightly lower than that of sampling chamber.This is because the diameter of the thin tube is small,and the flow shear is larger than that in the sampling chamber but not enough to destroy the polymer chain entanglement structure of the displacement fluid and not cause irreversible loss of sample viscosity. The sample viscosity can be maintained to the maximum extent during the sampling process, which is convenient to accurately test the true viscosity of the displacement fluid in the process.