Effects of petrophysical properties on time-lapse borehole radar logging

In the oil drilling, the downhole mud filtrate penetrates the porous reservoirs and alters the fluid distributions in the near-borehole zone. Adequate characterization of the invasion status is crucial for logging data correction and accurate reservoir assessment. Typically, the invasion depth is a key indicator for permeability estimation and an auxiliary variable for the version of virigin formation properties. In theory, time-lapse borehole radar loggings has demonstrated a potential on determining the mud invasion depth. A reliable borehole radar measurement heavily relies on the petrophysical properties of a reservoir. We conduct numerical investigations of a wide variety of reservoir properties based on a realistic scenario helping to analyze the influences of rock and fluid properties on the time-lapse borehole radar logging signals. The results show that the reflected signals from the mud invasion front is sensitive to the oil viscosity, porosity, mud salinity, formation water salinity, and ionic diffusion coefficient.