Plunger Slippage for Rod-Drawn Plunger Pumps

Abstract

A theoretical calculation is needed to predict pump slippage in a rod pumped well. Slippage lubricates the pump plunger and barrel and prevents galling of metals. Additionally, an estimate of plunger slippage is necessary to calculate pump efficiency. Historical plunger slippage equations have been proven incorrect by recent testing. A new method for calculating plunger pump slippage in rod pumped wells is introduced. This method involves calculating a velocity profile for an annulus with the inner wall moving parallel to the outer wall. An average velocity is determined for the annular fluid flow, which in turn is used to calculate the fluid slippage. The results are evaluated against the historical field data and compare favorably to recent testing for smaller plunger clearances. Work remains to be done at larger clearances.

A New Eccentric Annular Leakage Model for Rod Pump with Couette-Poiseuille Flow

“…l is the plunger length, m. And K, x, y is some coefficient whose values were differently taken by various theory models or experiments. The above formula is of high accuracy in some certain conditions, especially the model made by Richard Kyle Chambliss in his publication "Developing Plunger Slippage Equation For Rod-drawn Oil Well Pumps" [13] in 2005. The model mentioned in that paper detailed considered the influence of the pump leakage on the factor of the pump clearance, temperature and plunger piston eccentric equivalence.…”

“…In the 1940s, Davis [2] created the first theoretical model for pump leakage when he studied the heat transfer in annuli. From then on, Stearns [3], Reekstin [4], and Richard Kyle Chambliss [13,14] etc. put forward some new pump leakage models respectively.…”

Effective Method to Predict Installation of Plunger in a Gas Well

“…Many authors have investigated the performance and effectiveness of plunger lift technique. Chambliss et al [12] proposed a method to predict the pump slippage in a rod pumped well and the plunger slippage can be used to estimate the efficiency of pump. Lea [13] compared the performance of plunger lift with velocity string in gas well.…”