At the time of logging, the resistivity of a 10-lbm/gal drill- ing mud is measured with an instrument on the surface. A value of 1.52 2-meter is obtained at a temperature of 90 F. a. What is the apparent salinity of the mud? b. What is the estimated mud resistivity at a depth of 8,600 ft in the hole where the formation temperature is 180F? c. Estimate the resistivities of the mud filtrate at 90 and 180F. d. Can you justify the statistical approximation for predomi- nantly NaCl muds: Rmf=0.75Rm? e. Estimate the resistivity of the mudcake at 180 F. f. Can you justify the statistical approximation for predominately NaCI muds: Rme =1.5R,? %3D