Application of nanoparticle saturated injectant gases for enhanced oil recovery of heavy oils

Abstract

"Heavy oil, an immense U.S. oil resource, is untapped because its highly viscous nature makes it challenging to produce. The high cost and additional time associated with heavy oil production make it uneconomical compared with light oil production. Currently, heavy oil reservoir production challenges are mostly addressed by thermal recovery techniques. These techniques are generally successful because heat 'thins' heavy oil by reducing its viscosity. Carbon dioxide (CO₂) flooding is a well-known tertiary production technique used in depleted oil reservoirs. Supercritical CO₂ (SC-CO₂) dissolves in trapped oil and reduces oil viscosity by swelling it. More oil pushes towards the production well, with improved ability to move through pores in the rock. Metal nanoparticles are used for thermal conductivity enhancement of fluids. This thesis describes work carried out on copper oxide (CuO) metal nanoparticles, a sc-CO₂ soluble surfactant, and SC-CO₂. In another set of experiments, Viscosity Reducing Injectant (VRI), a miscible injectant used by Alaska North Slope operators, was used along with metal nanoparticles. The advantages of three different processes- thermal, chemical, and gas injection were merged together to devise a novel viscosity reducing process for heavy oil from the Alaska North Slope (ANS). ANS heavy oil displacement experiments were performed with metal nanoparticles and SC-CO₂ to determine the recovery factor of ANS heavy oil as compared to SC-CO₂ alone. A threefold reduction in viscosity and almost 22% increase in recovery factor were observed when metal nanoparticles, surfactant and SC-CO₂ were used as compared to SC-CO₂ alone"--Leaf iii