Downhole pump sand filtering snares

Abstract

Disclosed is a plunger for use in a sucker-rod pumping system. The plunger reciprocates within a barrel. The plunger comprises first, second, and third sections, in which the first and third sections are sealed against the barrel and in which a second section is between the first and third sections and in some embodiments may be a pull tube. A through passage for production fluid is provided, along with a pressure balancing chamber that is connected to the through passage via a sand snare, where the pressure balancing chamber is operable to equalize pressure on longitudinal sides of the seals, whereas the sand snare operates to restrain solids from reaching the pressure balancing chamber from the through passage (which is carrying the production fluid) and thereby create a slippage flow in the pressure balancing chamber, which equalizes pressure between the balancing chamber and the plunger's through passage. Further disclosed in embodiments a port between the second section and the first or third sections, where the port allows in one passage production fluid to pass through it between sections and in another passage or chamber allows slippage fluid to pass through it between sections.