A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT,ALBERTA PART 1: WHOLE OIL SAMPLES.

ABSTRACT

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. Relative to a core sample, the fireflood-produced oils exhibited a significant reduction in density and viscosity which began early in the production cycle. This behaviour was correlated with a marked increase in material boiling in the naphtha and middle distillate ranges and a concomitant decrease in the residue cut. The sulfur and nitrogen contents in the produced oils decreased relative to the core sample. A reduction in the acid number of the produced oil samples was coupled with an increase in the oxygen content as the firefiood proceeded. The relationship between these changes and the dynamics of the in situ combustion process are discussed.