The experience of working with extra-heavy oil producing wells profitably requires the use of available technologies to the limits of their capabilities. Due to its heavy use of electricity, the Electrical Submersible Pump (ESP) has often proven unsuitable for fields producing high-viscosity fluids. However, in some cases, given the conditions downhole and fluid behavior, along with technological changes, it has been possible to use ESPs at moderate cost.
Exploitation today has become technically and economically feasible for reservoirs in upper or lower layers that were previously uneconomical given lifting, transportation and marketing costs.
Previously discovered resevoirs in the Llanos Basin of Colombia were considered of no commercial value given the characteristics of its oil (higher viscosities to 1,000 cps at 60° F /14.7 psia and API gravities less than 10°). The Operating Companies of the same blocks discovered other, more easily exploited oil reservoir units. These oilfields, now in their mature stages, have high production costs because of the inevitable increase in water cut and/or decreased pressure. This has spurred to the use of existing infrastructure and advances in technology for lifting, processing and transportation of heavy and extra-heavy oil reservoir units already discovered.
There have been several challenges in developing extra-heavy oil wells, such as organic precipitation, presence of scales, strong emulsions and high GOR.
ESP technology has advanced in the extraction of large fluid volumes, smaller stage diameters, metallurgy resistant to corrosion and abrasive solids, stronger shafts, and conditions of high pressure and high temperature. However, there are very few developments in sustainable extraction of heavy oil and extra-heavy oil.
This article describes an example of implementing the Electro Submersible Pump as a feasible method for artificial lift in wells producing extra-heavy oil.