Innovative While-Drilling Dual Imager Provides Detailed near Wellbore Geological Interpretation and Aids Geosteering in Non-Conductive Mud

Borehole imaging through non-conductive mud while drilling remained a challenge for a long time for detailed geological interpretation. Introduction of new innovative dual imager addressed this limitation, rendering the while-drilling images for real-time applications and subsequently the recorded mode data for detailed geological interpretation; thereby helping the geologists with much needed data that was not available earlier without e-line.

This work presents the detailed geological interpretation achieved with the dual imager using complementary measurements of apparent resistivity and ultrasonic (amplitude and travel-time) overcoming the oil-base mud (OBM) challenges. The short sub (15-ft) acquires multiple images, with key information sent up-hole in real time for operational decisions, viz well placement achieving optimal NTG and subsequent stimulation planning.

The study-well used real-time apparent resistivity images for geosteering and recoded mode data for borehole shape analysis, expert dip-analysis, bedding and facies analysis along with the deformation episodes, sand counting, fracture and fault characterization and sand intrusions. Earlier these detailed interpretations were limited to e-line logged images only in wells drilled with OBM, with no high-def data available for real-time application. Even the legacy low-def images came at additional risk of chemical sources that has been eliminated as well with this approach.