An Experimental and Modeling Study on Interactions of Cold Lake Bitumen with CO2, C3, and C4 at High Temperatures

Abstract

Coinjecting CO2 and light hydrocarbons with steam into oil sand reservoirs can improve the efficiency of the SAGD (steam assisted gravity drainage) process by reducing the steam oil ratio (SOR). The effects of these solvents on bitumen recovery enhancement depend on reservoir properties and operating conditions. To investigate the effects of solvents on bitumen viscosity in a solvent aided process, phase behaviors and viscosities of CO2–, C3–, and C4–bitumen systems were measured and modeled at high temperatures. Using the calibrated Peng–Robinson equation of state (PR-EOS), the solubilities of solvents in the Clearwater bitumen sample from the Cold Lake region were predicted. High-pressure and high-temperature equipment using an electromagnetic-based viscometer was customized to measure the viscosities of CO2–, C3–, and C4–bitumen mixtures. The measured viscosity data were used to calibrate a nonlinear viscosity model which was used to predict liquid phase viscosity as a function of solvent solubility an...