Safety enhancement during deep well pump replacement

Abstract

In Ukraine, as in other countries of the world, the majority of oil wells are operated using a mechanical method of production, such as rod well pumping method, containing above-ground and underground equipment. For repair or replacement of underground equipment (down hole pump), is brought to the surface. In this case, the well may have oil-water gas inflow caused by the «piston» effect, for example. (Substitution of volume between the pump and the pump rods by fluid from the formation). This could lead to an open flowing well. Many additional complex operations are used to perform safe well workover operations, such as well closure. These operations are performed to control well formation pressure, prevent gas-oil and damage to downhole equipment. It is also worth paying attention to the fact that disruptions in the process of well closure can lead both to a decrease in its productivity and to the complete termination of its operation. To prevent oil-water gas inflow various equipment and devices are used: Cameron ram-type blowout preventer, wellhead stuffing boxes, emergency washers with gate valves, downhole shutoffs, downhole check valves. All this increases safety when replacing downhole equipment, but does not guarantee the avoidance of additional complications in the operation of this equipment: the possibility of controlled shutdown of the well, recovery of oil production without performance of downhole operations, etc. To eliminate these complications, a downhole check valve design was developed. Its design allows: not to change the arrangement of elements in the well; to change the pump without well closure (it reduces repair time and costs); undercut tubing (does not allow the fluid from the formation to enter the well and create an emergency situation that could lead to open well flowing).