Experimental Investigation of Solvent Co-Injection in Vapor and Liquid Phase To Enhance SAGD Performance

Abstract

Abstract Coinjecting solvent with steam under a steam-assisted gravity drainage (SAGD) process to reduce the required steam amount for heavy oil production has gained importance in recent years. The objective of this experimental study was to investigate the drainage mechanism for solvent co-injection in the vapor and liquid phases to improve production performance. A 2D cross-sectional low-pressure scaled physical model was constructed. The model represented a half-symmetry crosssection of a typical SAGD drainage in the Athabasca formation. Using an infrared camera, we visualize and record expansion of the steam chamber and temperature distribution. The fluid injection rate, pressure, and temperature, and produced liquid volumes were also recorded. The results show that the relative condensation time of solvent and steam results in different production performance. Solvent delivered in the vapor phase to the entire fluid interface reduces the bitumen viscosity along the whole vapor chamber boundary, but it may build a thick gas blanket that may reduce the heat transfer from the high-temperature vapor chamber to the surrounding low-temperature bitumen. Co-injecting a suitable multi-component solvent mixture, including a liquid solvent, can enhance the production performance by altering the condensation dynamics of the light hydrocarbons. The conclusions from this study can be used to design suitable solvent mixture and coinjection strategies to deliver higher production rate, higher recovery factor with lower cumulative steam required to oil ratio (CSOR), and lower cumulative energy required for oil production (CEOR) from SAGD performance.