| The usual objective of well logging is to determine the physical properties of underground formations and the nature of the fluids contained within the pore space. Porosity and fluid saturations are needed to estimate hydrocarbon reserves. Another rock property, permeability, is needed to estimate the expected flow rate from a particular formation. Obtaining estimates of permeability from borehole geophysical logs has always been difficult.;One of the complicating factors in formation analysis is the effect of mud filtrate invasion upon the measured log response. Mud filtrate invasion alters both the saturation profile and the salinity profile in the vicinity of the wellbore. The variation in saturation and salinity will be functions of both time and radial distance from the sandface. The magnitude of the saturation changes and the depth of the filtrate invasion are dependent upon the formation properties of permeability, porosity, relative permeability, and capillary pressure.;The ultimate objective of this research was to study the effect of various parameters upon the behavior of the resistivity profile and to develop a methodology for obtaining formation permeability from repeated induction logging. A parametric study has been performed using a numerical simulator to determine the effects of various reservoir parameters on induction tool resistivities. Results were generated from field data and analyzed to develop a correlating parameter which related reservoir permeability to the change in resistivity response with time. Actual field examples in which formations were logged repeatedly with induction tool devices were history-matched to verify the effectiveness of the correlating parameter and develop a methodology for obtaining formation permeability from repeated induction logging. |
