无杆泵井液力清蜡器运行规律模拟与试验研究

Simulation and Experimental Study on Operation of Hydraulic Wax Removal Device in Rodless Pumped Wells

清蜡器在油管内的运行规律对泵启停时间、装置回收时间和清蜡器换向胶筒的设计与选择有着重要的指导意义。为此,采用FLUENT软件,利用建立的清蜡器在井筒中运行的数学模型,通过编写UDF程序实现动网格功能,对清蜡器的运行规律进行了模拟研究,并采用试验方法对模拟进行了验证。研究结果表明:当管径和壁面摩擦因数不变时,清蜡器下行过程要经历短暂的加速运动,然后以平衡速度匀速向下运动;当管径和壁面摩擦因数变化时,清蜡器的运行速度将发生明显变化,根据清蜡器的运行规律可以合理确定采油泵的启停时间;清蜡器上行启动流量随着胶筒膨胀后外径的减小而增加,当胶筒外径小于某一临界值时,启动流量会显著增大,确定这一临界值对于胶筒的设计与选择、清蜡器的现场操作有着重要的指导意义。所得结论可为自动清蜡现场作业提供一定的参考依据。

The operation of the wax removal device in the tubing has important guiding significance for the pump start-stop time, the recovery time of the device and the design and selection of the reversing rubber cylinder of the device.In view of this, the FLUENT software is used to realize the dynamic mesh function by writing the UDF program based on the established mathematical model of the wax removal device operation in the wellbore.The operation law of the wax removal device is simulated and verified by testing.The following conclusions are obtained : given the constant tubing diameter and tubing wall friction coefficient, the downward process of the wax removal device undergoes a short acceleration motion, and then moves downward at a constant equilibrium speed.The running speed of the wax removal device will change significantly when the tubing diameter and tubing wall friction coefficient changes.According to the operation law of the wax removal device, the start-stop time of the oil pump can be properly determined.The upward starting flow rate of the wax removal device increases as the outer diameter of the expanded rubber cylinder decreases, and will experience a significant increase when outer diameter of the rubber cylinder is less than a certain critical value.Identifying this critical value has important guiding significance for the design and selection of the rubber cylinder and the field operation of the wax removal device.The study can provide a certain basis for the autom atic wax cleaning operation.