Until 1995, in the Cerro Negro area within the Orinoco belt of Venezuela, rod pumping units and top-drive progressive cavity pumps (PCPs) had been the traditional means of artificial lift for vertical and deviated wells, with production rates ranging from 200 to 600 BOPD of extra-heavy oil (8°API gravity and viscosities of 2,000 cp at a reservoir temperature of 133°F). More recently, with the implementation of horizontal drilling technologies for the construction of wells in unconsolidated sandstones, electrical submersibles pumps (ESPs) became an alternative to handle higher production volumes1 . Even more recently, top-drive PCPs have been installed in the Cerro Negro area to produce extra-heavy oil at high rates.

Hybrid artificial lift technologies, such as bottom-drive progressive cavity pumping, which combine features of the ESP and the PCP systems, have recently been successfully evaluated in the Orinoco belt to exploit extra-heavy oil reserves economically. A typical completion assembly includes a multisensor gauge to obtain downhole pressures, temperatures, vibration of the system, and power-cable current leaks; a 4-pole motor; protector; 4:1-ratio gear box; and the PCP. The functional design of the bottom-drive PCP facilitates the handling of viscous and abrasive fluids, increases the flow rate, and diminishes the operational costs. Advantages of this application also include the complete elimination of tubing wear by eliminating the rod string, greater torque capacity, lower surface maintenance, lower load and horsepower requirements, and less frictional losses.

The application of bottom-drive PCPs in the Cerro Negro area have resulted in production rates of up to 1,000 BOPD of extra-heavy oil with 50% less horsepower requirements in comparison to those of conventional top-drive PCP systems.

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