连续油管屈曲对环空摩擦压力损失的影响

针对带有非旋转屈曲内管柱的水平井，采用6种非牛顿流体，研究了连续油管管柱在3种流态区（层流区、过渡区和湍流区）和不同屈曲模式（正弦、过渡和螺旋）下对环空摩擦压力损失的影响，以及压力损失与流体流变性能（即屈服应力、粘稠指数和流动行为指数）之间的关系。结果表明，随着轴向压缩载荷的增加，摩擦压力损失显著降低。当使用具有更高屈服应力和更高剪切稀释能力的流体时，该效应更明显。此外，通过比较非压缩管柱和压缩管柱可以看出，随着轴向压缩载荷的增加，摩擦压力损失进一步减少。然而，对于低屈服应力、低粘稠指数、高流动性的流体，压缩管柱的影响则并不明显。

Experimental Investigation of Coiled Tubing Buckling Effect on Annular Frictional Pressure Losses

In view of the horizontal well with non-rotating buckling within a string, using six kinds of non-newtonian fluid, the effects of three flow regimes (laminar flow region, transition region and turbulent region) and different buckling modes (sinusoidal, transition and spiral) on the annular friction pressure loss, and the relationship between pressure loss and fluid rheological properties (yield stress, viscosity index and flow behavior index) were studied. The results show that the friction pressure loss decreases significantly with the increase of axial compression load. This effect is more pronounced when fluids with higher yield stress and higher shear dilution capacity are used. In addition, by comparing the non compressed and compressed inner strings, the friction pressure loss is further reduced with the increase of axial compression load. However, for fluids with low yield stress, low viscosity index and high fluidity, the effect of compressing the inner pipe is not obvious.