Views: 92 Author: Site Editor Publish Time: 2022-09-20 Origin: Site
Single screw pump in pumping some wells in the oil often encountered faults: rod break off, pump leakage, stator dissolution, stator degumming, tube leakage, etc., the following specific introduction.
Due to excessive load on the single screw pump connecting rod, wear or misoperation, etc., caused by rod breakage, decoupling or jerking the situation, specifically: in a short period of time, the pump efficiency dropped significantly, the dynamic liquid level rose rapidly, the current fell or even close to no-load current. Torque and axial force is still smooth and straight, but due to the lack of downhole pump working torque, light rod torque value is far less than the normal working range, axial force is missing the axial force generated by the liquid pressure on the rotor, so it is also less than the normal range, according to the broken off part, the axial force generated by the self-weight of the rod column is different, according to which the depth of the rod column broken off can be calculated.
Due to the single screw pump stator rubber wear, resulting in the stator and rotor interference reduced, the pump pressure-bearing capacity decreased. Therefore, the amount of leakage increases. Specific performance: pump efficiency gradually decreased, the dynamic liquid level gradually rose, the current gradually decreased. Due to the increased leakage, the pump active torque decreases and the torque is lower than the normal range. As the axial force generated by the liquid pressure decreases, the axial force is lower than the normal range, but still greater than the weight of the rod column in the extracted liquid.
Due to the action of the extraction fluid. Single screw pump stator rubber swelling occurs, resulting in increased stator-rotor interference, pump efficiency and dynamic liquid surface normal, the current increased, due to the large interference, the initial torque of the stator-rotor increased, so the light rod torque increased, more than the normal range, serious will cause stator-rotor clamping, but the axial force is normal.
Stator debonding is caused by insufficient stator bonding strength. Expression for the pump efficiency drops sharply, the dynamic liquid level rises, the current drops and fluctuates. When debonding, the active torque of the pump is zero, and the light rod torque drops greatly. In addition, irregular friction occurs between the stator and rotor due to debonding. The light rod torque will appear irregular liquid movement. The axial force generated by the liquid pressure is zero, therefore, the light rod axial force is lower than the normal category, but still higher than the weight of the rod column in the extracted liquid.
Tube leakage is caused by the existence of cracks in the oil tube wall. The phenomenon is a decline in pump efficiency, the dynamic liquid level rises, the current is reduced. As a result of the single screw pump work differential pressure decreases, the pump active torque decreases, the light rod torque is lower than the normal range, the axial force generated by the liquid pressure decreases, the light rod axial force is slightly lower than the normal range, but still higher than the weight of the rod column in the liquid.
This is the type of failure commonly encountered when pumping oil from a single screw pump in a well, and must be noted when in use.