Down hole well pumping apparatus and method

摘要

A method and apparatus for pumping formation liquids provides a reciprocating down hole pump on the end of a coiled tubing string. In one embodiment, one fluid flow path is provided through the inside of the coiled tubing and another flow path is provided in an annulus between the coiled tubing and a, production string. In one embodiment, pressure delivered down the annulus to the pump moves a piston in a direction to move formation liquids upwardly to the surface. When pressure in the annulus is reduced, the hydrostatic weight of the pumped liquid moves the piston in a retracting direction to prepare for the next stroke. In other embodiments, the piston is moved downwardly, in retracting direction, by fluid pressure applied from the surface.