(21) VSP AN UPDATE FROM 2001
A tried and true method of reducing gas interference in rod pumps is to set the pump in a position below all the perforations. The liquid and gas separate with the liquid dropping down to the pump intake and the gas rising in the casing-tubing annulus. This is not possible in today’s horizontally completed wells where the preferred pump placement is in the vertical section. In 2000 and an update in 2001 Benny Williams with Harbison Fischer presented papers regarding the then new Harbison-Fischer Variable Slippage Pump® (VSP®) patent #6,273,690 . In the last 24 months there has been an increase of interest of the VSP®. Many of these pumps have gone into these horizontally completed wells. The timing is good to update the paper with the large number of new wells being completed horizontally.