1. n. [Formation Evaluation]
The ability of a material to conduct electricity. It is the inverse of resistivity and is measured in siemens per meter (S/m) or mho/m. The conductivity is a property of the material, whereas the conductance also depends on the volume measured. The two are related by a system constant, which in simple cases is the length between the measurement electrodes divided by the area. In the most general case, the conductivity is the current density divided by the electric field and depends on the frequency of the applied signal.