Discussion of Interrelationship of Temperature and Wettability on the Relative Permeability of Heavy Oil in Diatomaceous Rocks

摘要

Schembre et al. (2006) interpret the effects of temperature on diatomite wettability and relative permeability for a specific set of laboratory conditions. These researchers imply that counter-current imbibition (CCI) of hot water and oil-driven by capillary-pressure forces-is the dominant mechanism in the thermal recovery of heavy oil from diatomite. While their results are appreciated and of theoretical interest, additional experimental work would seem to be necessary before conclusions can be drawn about field-scale key mechanisms and achievable-oil-displacement efficiencies. Several features of the testing procedures used by Schembre et al. (2006) prevent scaling their results from the laboratory to the field: extracted rather than preserved core material was used, dead-oil rather than live-oil was used, and the cores were not stressed during testing. Bennion et al. (1985) demonstrated the importance of measuring relative permeabilities using preserved core material, overburden stress conditions, and live crude oil. These types of relative permeability functions-rather than those measured using dead-oil and extracted cores that were unstressed-were very similar to those developed empirically by Coats et al. (1977) and Dietrich (1981) to reproduce cyclic-steam field performance. Bennion et al. (1985) found that laboratory-measured relative permeability curves from preserved core, when performed at reservoir conditions, do not need to be adjusted downward to match low water production typical of cyclic-steam response.