考虑井壁径向流入的大位移井井筒压降计算

WELLBORE PRESSURE DROP CALCULATION CONSIDERING THE RADIAL INFLOW THROUGH WALL IN THE EXTENDED REACH WELL

根据大位移井井筒流动特征 ,应用质量守衡、动量守衡原理建立了考虑井壁流体径向流入的任意倾角的大位移井筒压降计算模型。普通水平管内单相液流压降模型和Dikken的压降模型是所建模型的特例。在井筒为单相层流、紊流的情况下 ,对考虑了井壁流体流入的摩擦系数进行了分析讨论 ,对不同井长和井产量用实例分别计算了单相流情况下井筒的压力分布和压降。计算结果表明 ,在井筒较长、井产量较高时 ,不能忽略井筒压力降。

According to the characters of wellbore flow in the extended reach well, wellbore pressure drop calculation model considering radial inflow through wall in the extended reach well with arbitrary dip angle was established by using the principle of mass conservation and momentum conservation. The calculation model about monophasic fluid pressure drop in the ordinary horizontal pipe and the Dikken's pressure drop model are special examples of the model set up in this paper. Under the condition of laminar or turbulent flow in the wellbore, the wall friction factor considering inflow through wall was analyzed and discussed. As an applied example, the pressure distribution and pressure drop along the well bore of varying well-length and well production in the case of single-phase flow in the wallbore was calculated. The result of calculation shows that the pressure drop in the long well bore and high production can not be neglected.