HEAVY OIL PRODUCTION ENHANCEMENT BY VISCOSITY REDUCTION

This paper presents an evaluation of different chemical agents that can reduce dramatically the apparent viscosity of a heavy crude oil or a thick emulsion. This method can improve the production of heavy oils and very viscous emulsions such as are found in California. This method to reduce the backpressure from the well to the surface facilities improves well productivity. It is especially suited for produced fluids at relatively colder temperatures (less than 150 B0F). This laboratory investigation employed a unique novel viscometer built for this study that measures accurately the effective dynamic viscosity of multi‑phase liquids (emulsions) up to thousands of centipoise. Application: This chemical treatment strategy provides one option to increase productivity from wells making viscous emulsions. Because this method is suited for reducing viscosity even at cooler temperatures, it is attractive especially for treating viscous emulsions at locations with colder production. Results, Observations, Conclusions: By use of these chemical additives the viscosity of thick emulsions may be reduced, and in some cases by as much as a thousand fold. For example, for an oil from the Bakersfield area its viscosity reduced at room temperature from 50,000 cp to less than 100 cp with a chemical dosage o 400 ppm. The surfactant chemical systems that work for this process are fairly specific for each crude oil. . The new viscometer method based on the sensitive measurement of torque in a stirred cell can determine the dynamic viscosity of emulsions at shear rates representative of that found in flowlines. Significance of Subject Matter: This study demonstrates selected chemical additives can reduce greatly the backpressure associated with production of thick viscous emulsions. The development of a new tool to measure the viscosity of emulsions of multi‑phase fluids at conditions representative of pipe flow. .