This post in a LinkedIn group that I follow, linking to this article, got me thinking a bit about wettability. I was struck by the comment that “conventional wisdom says that clays are always water-wet”. The article makes good use of pretty advanced analysis and imaging technologies to show that this is not (always) the case. We can show evidence for similar effects using the rather more mundane thin-section petrography, and can add that we very commonly see illite-cements, in particular, that are very heavily oil stained (implying some degree of hydrocarbon wettability) while other mineral surfaces are oil-free.
When we bought our bench-top SEM a few months ago, I thought it would be interesting to revisit this sample, which is one that I spent a lot of time looking at when I was a PhD student ( … back in the day … sigh). I also read a piece in today’s paper that gave me pause to think about just how much I (try not to) take for granted in my day-to-day work .