Dual Pumping System to Reduce Coning
Publication Date: 2005-Jan-27
The IP.com Prior Art Database
In oil production fluid is produced by lowering the lever of the fluid in the well bore (pumping). This lowers the pressure at the formation face, forcing the fluid to flow the reservoir into the well bore. The ease at which the fluid will flow depends on the viscosity of the fluid. Water which often encountered in oil wells is generally heavier and lies beneath the oil layer. As the oil is pumped, the water which has a viscosity significantly less than the oil will tend to rise or "cone" in the localized area around the well bore. This rising water will displace the oil and reduces or shut off the oil flow. A technique referred as "Reverse Coning" attempts to defeat this tendency by producing the water from a second set of perforations below the perforations for the oil. The water is removed at a rate that is high enough to prevent the water cone from rising and shutting off the oil. Reverse coning has been done with two separate pumps, requiring two power systems and duplication of equipment in the well bore. This disclosure describes methods and equipment developed so that a single motor can be used with a set of pumps in tandem to accomplish the reverse coning phenomena. The arraignment requires a packer that is set when the pump is landed. The motor, seal and first pump are below the packer. This lower pump produces the information water from the lower part of the zone. This packer is penetrated by the electrical cable going down to the motor, and by a upward hydraulic passage for the pumped water and the rotating pump shaft which drives the upper pump. The upper pump has an entrance for the oil in the annulus directly above the packer and also takes the fluid from the lower pump. The upper pump is sized so it can produce the total volume from both sets of perforations. A remotely operated value can be incorporated with the upper pump intake to allow for regulation of the flow into the upper pump. The ratio of flow between the pumps can be adjusted with this valve in combination with other valves or varying the speed of the motor.