Every standard down hole sucker rod pump slips fluid between the plunger and the barrel. This is necessary because they all look to the formation fluid for lubrication to enable the plunger to move up and down in the barrel. Slipping fluids causes several problems. In addition to poor pump efficiencies, if there are solids in the formation fluid, such as formation sand, frac sand, iron sulfide and scale, the pump may experience premature failure. The solids cut the plunger and the barrel increasing the clearance between them, further reducing the pump efficiency. Even more, in certain conditions, the plunger may stick and not pump at all.
Self lubricated plungers are equipped with seals on each end. The seals perform two vital functions. They trap a Teflon based liquid lubricant, and they prevent the formation fluid and whatever solids may be in the fluid from getting between the plunger and barrel. Consequently, the pump is self lubricated with the barrel coated with its own lubricant on every up and down stroke. In addition, formation fluid is not allowed to travel between the plunger and barrel, thereby avoiding wear, pump sticking and accumulation of deposits.
The purpose of this paper is to present to oil producers the advantages experienced with sucker rod pumps equipped with self lubricated plungers in the oilfields of "Pico Truncado", "El Cordón" and "Cañadón León", all located in the north of Santa Cruz, Argentina.