A dielectric logging tool with insulated collar for formation fluid detection around borehole

Abstract A dielectric tool with insulated collar for analyzing fluid saturation outside a borehole was introduced. The UWB (ultra-wideband) antenna mounted on the tool was optimized to launch a transient pulse. The broadband evaluation method provided more advantages when compared with traditional dielectric tools. The EM (electromagnetic) power distribution outside the borehole was studied, and it was shown that energy was propagated in two modes. Furthermore, the mechanism of the modes was discussed. In order to increase this tools' investigation depth, a novel insulated collar was introduced. In addition, operation in difference formations was discussed and this tool proved to be able to efficiently launch lateral EM waves. Response voltages indicated that the proposed scheme was able to evaluate the fluid saturation of reservoir formations and dielectric dispersion properties. It may be used as an alternative tool for imaging logging applications.