Patent ID: 7870900
Filing Date: 2011-01-18
Classification: E21B

Abstract:
1. A method of controlling pump speed of a progressing cavity pump ( 10 ) to increase liquid production from a well ( 80 ) while avoiding operation of the well ( 80 ) in a pumped-off state, said method comprising the steps of: controlling a variable speed drive ( measuring a current flow rate of liquid production from the well ( receiving said current flow rate signal in said controller ( determining a differential flow rate signal with said controller ( controlling said variable speed drive ( increasing said set pump speed by a step change when the differential flow rate signal indicates an increase in the current flow rate, decreasing said set pump speed by a step change when the differential flow rate signal indicates a decrease in the current flow rate, increasing said set pump speed by a step change when the differential flow rate signal indicates no change in current flow rate and said set pump speed was previously decreased, and decreasing said set pump speed by a step change when the differential flow rate signal indicates no change in current flow rate and said set pump speed was previously increased.