稠油水平井杆管摩擦载荷预测新模型

A NEW METHOD TO PREDICT THE FRICTION LOAD BETWEEN ROD AND TUBING IN HORIZONTAL WELLS FOR HEAVY OIL

水平井有杆抽油系统在抽汲周期内上、下冲程摩擦载荷差异较大,且随着稠油粘度逐渐增加,上、下冲程摩擦载荷的差异进一步加大,导致采用一个平均阻尼系数来描述整个井筒的摩擦载荷存在较大误差,难以准确描述其变化规律。基于水平井筒压力、温度和粘度剖面,根据环空液体流动方程和Navier-stokes方程,建立了稠油水平井杆管摩擦载荷计算模型,并首次提出了采用上、下阻尼系数来分别描述上、下冲程摩擦载荷,解决了稠油井上下冲程摩擦载荷差异较大的难题。以克拉玛依油田16口稠油水平井为例,计算结果表明新方法预测的悬点载荷计算值与实测值比较接近,完全满足生产要求。

It is obvious that the friction load of sucker-rod pumping system during up and down stroke in the pumping cycle is very different for horizontal wells. As the viscosity of heavy oil gradually increases,the difference about the friction load of the upper and lower stroke increase further,so it will have a large error to use an average damping factor to describe the friction load of entire wellbore,and it is difficult to accurately describe the variation. Based on accurately predicting the pressure,temperature and viscosity of the horizontal wellbore, according to annular fluid flow equation and the Navier-Stokes equations,a model is established to calculate the friction load between rod and tubing in horizontal wells for heavy oil,and a dual-damping method is proposed to calculate friction load factor in up and down stroke,and it is good to solve the larger problem about the difference of friction load during up and down stroke. Take 16 horizontal wells for heavy oil in the Karamay oil field for example,the results show that the predictions of the model are in good agreement with measured data,so the new method can fully meet the production requirements.