Efforts to Further Optimize VFD Controllers


Chance Hukaby and Chris Cavazos, Occidental Petroleum Corp 

Variable Frequency Drives (VFDs) are an advanced type of beam pump-off controller with the ability to increase or decrease pumping speed. This facilitates drawing down the fluid level to near pump off conditions and maintaining a constant bottom hole pressure, all while running 24 hours per day. VFD’s have been able to successfully reduce the failure frequency in the most problematic wells, and in some cases, increase production as well. This presentation will illustrate a systematic approach to a few common problems when operating VFD controlled wells. By design, these controllers run 24 hours per day with some degree of incomplete pump fillage, which can be costly to the operator. One of the problems we attempted to resolve was our ability to significantly reduce the amount of incomplete pump fillage, and gas compression visible in the dynamometer cards by optimizing the controller settings. The other problem that was addressed was to solve was the ability to better control wells with Mark II beam pumping units, because of the challenges their unique geometry presents in rod pumped wells. In conclusion, VFD controlled wells have shown improvement in regards to failure frequency reduction, and increased production compared to producing with a standard pump off controller. By further optimizing their settings, we can increase their utility in a greater population of rod pumped wells.