Producing Extra-Heavy Oil From the Orinoco Belt, Cerro Negro Area, Venezuela, Using Bottom-Drive Progressive Cavity Pumps

Abstract

Summary The traditional means of artificial lift production for vertical and deviated wells in the Orinoco oil belt in eastern Venezuela used to be rod pumping and top-drive progressive cavity pumps (PCPs), particularly for wells with production rates ranging from 200 to 600 barrels of oil per day (BOPD) of extra-heavy oil (8°API gravity and viscosities of 2,000 cp at a reservoir temperature of 133°F). After 1995, with the implementation of horizontal drilling technologies for the construction of wells in unconsolidated sandstones, electrical submersible pumps (ESPs) became an alternative to handle higher production volumes (Ramos and Rojas 2001). More recently, top-drive PCPs have also been installed 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, and vibration amplitudes of the system, and to detect power-cable current leaks; a four-pole motor; a protector; a 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. Further advantages of this application include the complete elimination of tubing wear by eliminating the need for a rod string, greater torque capacity, lower surface maintenance cost, lower load and horsepower requirements, and lower frictional losses. The application of bottom-drive PCPs in the Cerro Negro area has resulted in production rates of up to 1,000 BOPD of extra-heavy oil with 50% lower horsepower requirements in comparison to those of conventional top-drive PCP systems.