注入比对水平井筒压降影响规律的研究

采用定常湍流N—S方程，数值模拟了水平井筒湍流变质量流场，通过分析轴线压降和孔眼附近三维流线图，研究注入比对水平井筒压降的影响规律及混合压降产生的机理。结果表明，存在一个临界注入比，当注入比小于临界注入比时，射孔入流流动形式主要表现为紧贴壁面的附体流动，对主流扰动小，此时混合压降很小甚至可以忽略，总压降损失近似等于没有孔眼入流情况下的摩擦压降损失；当注入比大于临界注入比时，孔眼入流可以深入主流并在孔眼下游出现低压分离区，引起混合压降损失，该压降损失随注入比的增大而显著增大，从而导致总压降随注入比增大而急剧增加。

Effects of injection ratio on pressure drop in horizontal wells

The turbulent flow field in the horizontal well completed with perforation was simulated by solving the N-S equations. The effects of injection ratio on pressure drop and the mechanism of mixing pressure drop were studied by the analysis of axial pressure drop and three dimensional stream lines. It can be concluded that there is a critical injection ratio, less than which the injection fluid flows near the wall with little disturbance, the induced mixing pressure drop is very little, even can be neglected, and the total pressure drop equals approximately to the friction pressure drop without injection flow. When the injection ratio is higher than the critical injection ratio, the injection fluid flows deeply into the main flow and induces one separation region with large energy loss, so the mixing pressure drop plays an important role, it increases with the injection ratio increasing, which leads to sharp increase of the total pressure drop.