A Fluid Based System for The Digitization of Ultrasonic Borehole Televiewer Data In Realtime


Douglas Schmitt, University of Alberta


A system for the digitization of borehole televiewer ultrasonic pulse amplitudes and travel-times has been constructed. The digitizer is based in a personal computer and interfaces transparently to existing conventional analog televiewer surface output. The new equipment allows real time digitization during logging and immediate quality control display after logging. Deployment of the tool in a highly fractured formation suggests that fractures seen only in the digital travel-time image are the most permeable. Further, these fractures predominantly dip in the direction of the least compressive principal stress and may be a simple indicator of crustal stress directions. In a second application, pulse travel-times from a horizontal borehole drilled in a sedimentary formation delineate a cross-sectional shape reminiscent of a keyhole as would be expected from the abrasion of the drill pipe resting on the borehole floor.