1. n. [Enhanced Oil Recovery]

In a system with two immiscible fluids in contact with a solid, the difference in the two fluid-solid surface tensions. In thermodynamic equilibrium this difference is equivalent as a result of the Young-Laplace equation to the product of the interfacial tension between the two fluids and the cosine of the contact angle at the fluid/fluid/solid interface. As the combination of these two individual interfacial terms, adhesion tension is a useful measure of the wetting character of a petroleum reservoir's pore system.

See: contact angle,  interfacial tension,  wettability,  Young-Laplace equation