Travels vertically utilizing pressure differences to transfer fluid from below the standing valve into the pump chamber and to tubing for surface production via traveling valve;
Located above the standing valve and pump chamber moving vertically with the sucker-rods acting to hold fluid in chamber and also bring fluid to surface on the upstroke.
At point B, the standing valve with open allowing fluid to enter from the tubing into the chamber as a result of pressure differential from higher tubing pressure to below the pump intake pressure.
At point C, the downstroke begins and the standing valve will close halting fluid intake.
Swabbing the well with pulling unit is pumping the well with longer stoke length and fast stroke per minute which causes more pressure drop to move the heavy oil or to free the standing valve from remaining debris.
Flushing means dumping hot water through the annulus which help to reduce heavy oil viscosity and to clean the standing valve, which increase pumping efficiency.
In addition to that hanging the standing valve ball is representing a major problem in heavy oil production which result in more down time, down time for swabbing, high operating cost and oil production drop, To overcome this problem, the pump speed need to be optimized using motor sheaves, in addition to set a periodical schedule for CSG flush.