Alteration of wettability and wettability heterogeneity

This paper emphasizes how wettability may be altered for special core analysis purposes and by which processes this occurs. Studies of how the imbibition characteristics change after aging core plugs in crude oil are reported, focusing on imbibition rate and endpoint saturations and on the induction time. Imbibition characteristics after wettability alteration by aging core plugs submerged in crude oil at elevated temperature are compared to the effects from aging procedures, where crude oil is continuously flushed through the core plugs during the aging and after simply leaving the plug at connate water saturation under static, i.e. no flow conditions, shows different significant results. The results show that: (1) continuously introducing fresh crude oil boosts the aging process and (2) a significant impact on the wettability alteration as a function of core length is observed, reflecting the absorption of active components for the wettability alteration process. In an integrated study consisting of experiments and numerical simulation, this paper also demonstrates the importance of close interaction between how to alter the wettability, applications of the technique in core analysis and numerical simulations of the latter. Finally, the significance of some sensitive parameters is demonstrated. (C) 2002 Elsevier Science B.V. All rights reserved.