Fluid loss reduction between a cylinder and plunger during operation is the most important requirement to the design of a bottom-hole sucker-rod pump. Fluid loss reduction in the clearance between a cylinder and plunger increases the pump efficiency. Current methods for leakage control do not provide the intended effect. As the pump runs, the gap between the cylinder and plunger increases due to wear, resulting in fluid leakage increase. An attempt to use a hydraulic seal does not provide the intended effect as well. Over time, the seal is washed out and loses its functionality. Therefore, there is a need to develop more reliable, simple and effective control methods against this harmful phenomenon.
This paper proposes using the hydrostatic head pressure (which leads to fluid leakage) to reduce leakage. This is achieved by opening the side angle holes in the plunger. Mathematical model is developed and fluid leakage at the clearance between cylinder and piston of the pump with presence of holes on the lateral surface is determined. Numerical calculation is performed and threshold values of lateral holes’ coordinates are determined, excess of which makes them inoperative. Level of leakage reduction is determined depending on parameters of the lateral holes.
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