Rocks and wettability

Discussion of wettability in porous media

[@JohnParra-u2o]

Thanks Professor. Well elaborated explanations. I understand the contact angle between a drop of phase 1 with solid, immerse in a phase 2 media. However, in an oil reservoir with water-wet preference, water is not in drop form but rather as layers coating a solid matrix. How contact angle could be illustrated in such cases ? Other question is about contact angle change as phase 1 displaces phases 2, depicted in 12:47. The curvature change suggests that in water-wet waterflood cases (assuming that same formation water is reinjected to not disturb the ionic balance) there could be a wettability alteration ? Many thanks.

[@BoffyBlunt]

The contact angle is defined wherever the two fluid phases contact the solid, regardless of the morphology of the phases - we can have drops or layers, for instance. For your second question, yes, in the diagram there has been a wettability alteration, so that the advancing (water flooding) contact angle is larger than the receding angle.

[@mohammadpirahmadi8288]

Thank you sir ❤❤❤