聚合物驱抽油机井摩擦载荷的计算

Calculation of friction load on rod string in polymer flooding wells.

聚合物驱抽油井见聚合物后,产出液为非牛顿流体,其粘度随剪切速率的变化而变化,计算抽油杆柱摩擦载荷时,要取相应剪切速率下的粘度值。由给出的上、下冲程抽油杆柱摩擦载荷的计算公式可知,聚合物驱井见聚后,摩擦载荷随冲次的增加而显著增大,所以应尽量采取低冲次参数抽油。孤东油田八区部分见聚油井摩擦载荷的计算值与实测值的实例对比表明,二者的数值差距很小,表明计算方法可行。

When the polymer is found to be produced along with the crude oil in a polymer flooding well, the produced fluid becomes a non-Newton fluid, whose viscosity varies with the change of the shearing rate. Therefore if the frcition load on the rod string is calculated, the value of the viscosity at the corresponding shearing rate should be selected. According to the calculating equations of the friction load on the rod string on the upstroke and downstroke, the friction load increases remarkably with the increase of pumping speed when the polymer is found to be produced from the well, therefore low pumping speed should be adopted during oil production. Case study shows that the calculated value and the measured value of the friction load is very close, this means the above-mentioned calculation method is feasible.