After years of listening to sounds far below the earth's surface, Lewis Katz decided his methods could help oil and gas drillers steer a straighter course in their search for new wells. The result is a new technique that industry sources say could bring new sales of $150 million to $200 million per year to his company, Utah Geophysical Inc., of Salt Lake City.

Utah Geophysical provides geophysical seismic services, primarily to companies looking for reservoirs of superheated underground water that can be tapped as a source of geothermal power. Katz reasoned that he could adapt his geothermal listening techniques and monitor the sound of a drill as it bored through the earth, record the data, and analyze it by computer. The result, which has been borne out in field trials in Texas, is a method of accurately pinpointing both the angle and direction of a drill bit miles below the earth's surface.

That ability has eluded drillers for decades. If a drill bit strays off course, it might miss a promising oil or gas-bearing formation, so accuracy is important. But to check the progress of a drill, the driller has to pull up all of the drill pipe already put down and send survey equipment into the hole, then recover the instruments and send the drill back down again. It is a time-consuming and costly process.

With additional funding Katz plans to build a minicomputer for continuous on-site analysis of data received from listening posts, permitting the drill rig operator to work without interruption and to know just where his equipment is going.