A borehole televiewer uses acoustic pulses to produce a camera-like picture of downhole conditions. A block diagram shows the borehole televiewer logging system. The diameter of the tool is 3-3/8 in., but slimmer tools can be built. The nominal logging speed is 15 ft per min. Vertical fractures will show on the log as double vertical lines, horizontal fractures as single horizontal lines, and dipping fractures as curves that are roughly symmetrical. The orientation of the minimum of the curve is the dip direction of the fracture. The original idea was to find a tool to give guidance in fracturing jobs, and so far the tool has been primarily used for that purpose. It will also be a tremendous help for geologists and engineers on wildcate wells who have to make the agonizing decision to complete or abandon. It will show fracture porosity that no other currently available tool will show. It also will be a very useful supplement for the dipmeter. It can accurately locate vugs and washouts, and show changes in porosity and lithology. Mobil Oil is now using the tool as a standard log on all its wildcat wells.