稠油定向井扶正器优选及分布设计

OPTIMAL SELECTION AND THE CENTRALIZED DISTRIBUTION DESIGN OF CENTRALIZER FOR DIRECTIONAL WELLS IN HEAVY OIL RESERVOIR

有杆泵作为稠油定向井重要的人工举升方式之一,一般需下扶正器来减少斜井段抽油杆与油管之间摩擦,避免油管被磨穿或抽油杆因截面积缩小而产生应力集中被破坏,但过多且密集的扶正器可能出现喉道效应,使其流动阻力急剧增加。文章选取新疆油田常用的3种扶正器,基于计算流体动力学方法模拟了不同稠油黏度、流速条件下的流场分布,总结得出了3种扶正器相应的压降规律,合理选择扶正器;并基于梁弯曲理论设计扶正器间距,综合考虑全角及摩擦力剖面,利用无因次处理方法建立了扶正器合理分布综合评价模型,通过在定向井关键位置布扶正器,在保证抽油杆柱扶正的同时降低了扶正器的数量。其研究成果对于定向井使用有杆泵抽稠具有重要的实用价值。

The centralizer is a necessary downhole tool in rod pumping system in direction well.In order to pump much heavy oil,the rod pump is always installed at top of the producing pay.Excessive centralizers probably bring throat effect,and sharply raise the flow resistance.Collecting 3 kinds of centralizers used for Xinjiang oilfield,based on computational fluid dynamics,a mathematical mode was established which describe the flowing orderliness in well tubing where oil flow through the cenlralizer.After simulating the flow field distribution in different well deviation,different viscosity and different velocity,the corresponding pressure fall regular patterns of the 3 kinds of centralizers were summed up and it provide the basis for optimal selection of centralizer.Comprehensive considering over all angle and friction surface,according to beam bending theory,an evaluation model of the reasonable centralizer distribution was build up by using dimensionless method.By installing centralizer in necessary position,the amount of centralizer was effectively lowered in the premise of upright of the rod string.This paper provided practical value for rod pumping techniques of heavy oil directional wells.