连续油管内流体压力损失研究进展

RESEARCH ON PRESSURE LOSS OF FLUID IN COILED TUBING

连续油管内流体可能为水、钻井液、泡沫、含钻屑的混合物等,涉及到牛顿流体和非牛顿流体,一般情况下其流态为紊流。通过边界层理论可以对管内流体的摩擦压力损失进行理论分析,从而得到减阻的途径。但由于流体本身性质及流场形状的复杂性,实验成为研究压力损失的主要手段。概述了国外近十年来关于连续油管内流体的摩擦压力损失、流体和油管之间的相互作用、岩屑传输等方面的最新研究进展,主要有连续油管中的压力损失随着流量和油管曲率的增大而增大;泥浆的含沙量以及泡沫流中的泡沫含量均会增大摩擦损失;聚合物具有减阻的作用,且减阻效果与紊流度密切相关,同时紊流度的大小也是影响岩屑传输的根本原因。基于目前的研究现状,提出了需要进一步深入研究的问题。

The fluid in coiled tubing includes water,slurry,foam,mixture of fluid and cutting and so on,that is Newtonian fluid or non-Newtonian fluid.Generally,the flow regime is turbulence.The boundary layer approximation method could be applied to the theoretical analysis of friction loss of fluid in coiled tubing,and the approach to drag reduction has been explored.Anyway,because of complexity of the fluid character and shape of flow field,experiment is the main way in studying pressure loss.Here overseas advances in the fluid friction loss,interaction between tubing and fluid and cutting transport during recent decade have been reviewed,and the new discoveries is as follow:fluid pressure loss in coiled tubing will increase along with flow rate and tubing curvature;the higher sand concentration of slurry and foam quality of foam fluid improve the friction pressure loss;polymeric fluid has the character of drag-reduction,and turbulence level has much to do with effect of drag-reduction;meanwhile turbulence level is also crucial in cutting transport.Base upon review,the issues that should been studied next have been put forward.