Paper: THE THREE CAUSES OF INCOMPLETE PUMP FILLAGE AND HOW TO DIAGNOSE THEM CORRECLTY FROM DYNAMOMETER AND FLUID LEVEL SURVEYS

Incomplete pump fillage is often associated erroneously with a "pumped-off well", meaning that the pump displacement exceeds the production capacity of the reservoir, ignoring the fact that there are two other causes of partial liquid fillage: gas interference and the presence of a flow restriction or excessive pressure drop at the pump intake. The result of a misdiagnosis is to incorrectly set the mode of operation of pump-off controllers, variable speed drives or timers thereby loosing significant amounts of production. This paper describes the three causes of incomplete pump fillage, presents several sets of field data for the various cases, discusses how to combine dynamometer and fluid level records to correctly identify the source of the problem and presents recommendations for possible solutions.