Plugging of sucker-rod pump’s valves with solids, wax, floating debris, etc. while well operation are an expensive and a time-consuming challenge. The available downhole equipment does not allow for direct washing of the pump’s valves, while backwashing is often ineffective, because of settling of suspended particles in the pump and because of circulation losses. The currently used downhole pumping equipment can only be used for bottomhole zone treatment in wells with tubing sucker-rod pumps. A modified sucker-rod pump can solve two tasks simultaneously: well servicing with direct washing of the valve assembly and bottomhole zone treatment without inviting workover crews. This will increase the time between repairs and decrease OPEX associated with wellbore intervention jobs.
The sucker-rod pump design comprises conventional assemblies and components, save a modified suction valve assembly. The latter is equipped with a mechanism of displacement of the ball of the valves pair when the plunger is submerged below the bottom end of the stroke until stop. Successful rig tests, followed by field tests in two Tatneft PJSC wells confirmed performability of the modified sucker-rod pump. During field operation, two operation modes were tested: a) direct pumping of fluid by complete unloading of the rod string; b) pump discharge with testing of traveling and standing valves for leakage. This paper presents a detailed description of the sucker-rod pump design, the procedure and the results of the field tests.
