|
Description:
|
A 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 leakage is necessary to calculate pump efficiency . If the leakage is too small , the plunger and barrel are not properly lubricated ; too much leakage causes low volumetric efficiency thus low power system efficiency . Historical plunger leakage equations have been proven incorrect by recent testing . A theoretical method has been developed to calculate pump slippage , but a new experimentally derived formula is needed .
Historical pump slippage formulas predict slippage that varies by a factor of 20 or more depending on the pump and fluid variables . Most of these formulas were derived from experimental data gathered in the 1930’s and 1940’s . A formula developed in the late 1990’s by ARCO and Harbison Fischer predicts a slippage that is much less than slippage predicted by the older historical formulas . The ARCO - Harbison Fischer formula was considered to be incomplete because a very limited amount of data was collected and pumping speed was not a variable that was studied . It is believed from theory and field practice that pumping speed does not affect slippage .
The purpose of this dissertation will be to develop a new slippage equation that is usable in the field and to gain a better understanding of the fundamentals of fluid slippage . This will be done using extensive test data from a test well and by improving upon past theoretical equations and by developing new theoretical equations from lessons learned from the well test . |