Fluid Phase Behavior for Conventional and Unconventional Oil and Gas Reservoirs

1.4. Interfacial Tension

Interfacial tension (IFT) is known as one of the most important parameters affecting sweep efficiency, particularly during enhanced oil recovery processes such as gas flooding. When two immiscible phases are in contact, the surface layer between the two phases is in tension due to an imbalance of molecular forces at the interface. The forces on the molecules located on the surface of a phase differing from the molecules in the bulk and the surface layer tend to form the smallest area. Generally, the IFT between a liquid and a vapor is called surface tension.

IFT is defined as the energy required to impose an increase in the surface area.

σ=[∂G∂A]T,V,N

(1.194)

There are several experimental methods for IFT measurement such ...