Examination of viscous fingering using the Cat-Scanner

Abstract

Miscible enhanced oil recovery (EOR) is oil recovery by the injection of fluids which are miscible or develop miscibility with the reservoir crude oil. Miscible EOR uses solvents such as flue gas, nitrogen and carbon dioxide. This EOR process suffers from poor displacement efficiency primarily because of the viscosity difference between the two fluids. This phenomena is called "viscous fingering" which causes the solvent to bypass the oil, resulting in premature solvent breakthrough. Viscous fingering is believed to be partly initiated by rock heterogeneities. To study viscous fingering, a Cat-Scanner was used to visualize the in-situ fluid displacement mechanism in Berea sandstone cores. The Cat-Scanner cross-sectional images of -the core were analyzed using the CATPIX ImageTool software on a SPARCstation II computer. One purpose of this work is to provide experimental data to investigate the use of dimensionless groups to analyze viscous fingering. Although this experimental work is beyond the scope of this thesis, the dimensionless groups will be briefly discussed.