Wetting behaviour of initially dry reservoir cores:

The capillary rise technique.

^aBaldev S. Gill, Geoffrey F. Hewitt and ^aAlexander Bismarck

Imperial College London, Department of Chemical Engineering, South Kensington, London SW7 2AZ

This paper deals with the characterisation of the wetting behaviour of dry reservoir core samples by various liquids including asphaltic crude oil. We will use the capillary rise method to determine the wetting rates of these liquids in the porous rock. The critical solid surface tension of the reservoir rock will be determined using a modified version of the Washburn equation. Below this surface tension of the solid any liquid will fully wet the porous rock and above the critical value the liquids are partial wetting, i.e. display a finite contact angle. We initially conduct experiments using different core samples and use both polar and non-polar test liquids. We then continue to use North Sea crude oil samples (with and without asphaltene) to determine the wetting behaviour for the samples under investigation. We can evaluate how the rock is wetted by the crude oil samples using this method and can make both qualitative and quantative comparison of the wettability and its affect on the rock samples. It is important to note that a distinct difference between the asphaltic crude oil versus the cleaned sample exists.

^aCorresponding Authors: E-mail addresses: baldev.gill@imperial.ac.uk (Baldev S. Gill) and a.bismarck@imperial.ac.uk (Alexander Bismarck)