The formula to calculate the mud resistivity is:
\[ R_m = \frac{C_m}{R} \]
Where:
Mud resistivity is a measure of the electrical resistivity of drilling mud, which is a fluid used in the drilling of boreholes. The resistivity of the mud is an important parameter in the logging and evaluation of subsurface formations. It helps in identifying the presence of hydrocarbons and determining the porosity and permeability of the formations. Mud resistivity is influenced by the composition of the mud, including the type and concentration of solids and fluids, as well as the temperature and pressure conditions in the borehole.