GEOLOGISTS NOW SEARCH FOR OIL USING computer programs that turn seismic data into pictures of the structures deep below the ground. But the approach may not be "seeing" all the oil under the Gulf of Mexico. That's because a thick layer of salt lies under much of the gulf's seabed. "The salt layer acts like a big lens that directs seismic signals off to the side or deflects them back up at you," says David E. Womble, a mathematician at Sandia National Laboratories. "Hardly any energy can get through, so the images are very blurred."
It is possible to clear up the pictures somewhat by repeatedly processing the data, but this takes so long--months of supercomputer time--that Arco says it doesn't even bother. So Womble and a team of Sandia scientists have invented new algorithms that magically gather in all the data on reflections, creating sharp images in just a few hours.
Geophysicists think the technique could also help decipher seismic data from the Rocky Mountains region and find new oil there, too. The new formulas are still being perfected, but they're already being incorporated into programs for supercomputers from Cray Research, Intel, and IBM. Commercial software could be ready by 1997.