Using Gravity Data in the Largest Underexplored Paleozoic Basin in the U.S. Great Basin

The Great Basin of eastern Nevada and western Utah boasts of having a well that kept the record for the most prolific North American onshore flowing oil well for ten years. Though a flurry of exploration activity followed the discovery, the source of the oil remains illusive because the area lacks an adequate geologic map. The discovery of the Mississippian oil in central Utah on the eastern edge of the Great Basin adds additional frustration to comprehending the regional petroleum geology because the fields lie beyond the thick, organic-rich Mississippian Antler Basin source rocks.

Many exploration companies have thrown lots of money at Great Basin 2-D seismic data that provides little or no useful reflections in the Paleozoic section. Popular and unproven Great Basin structural models appear to have affected the location of the few significantly deeper tests in the basin.

Apparently oil and gas resource companies hesitate to explore the region because they cannot predict the structural configuration of promising oil and gas opportunities in both conventional and unconventional (shale/oil gas) exploration. Therefore, exploration companies have failed to find major new discoveries in this very promising region, lacking appropriate basic exploration tools. A new proprietary Great Basin gravity survey offers a basic exploration tool that would fill some of the gap in data coverage caused by the lack of an adequate geological survey and deep tests.

Older commercial gravity data are composed of disparate gravity surveys mostly in valleys of many vintages and quality. A modern state-of-the-art proprietary gravity survey mostly in the mountains provides the data necessary to merge the disparate commercial surveys. The merge greatly upgrades the commercial gravity surveys.

Some of the immediate results of the merge include gravity features that may be excellent drilling targets, revelation that many valleys were depocenters for Oligocene ignimbrite falls and flows, an indication of depth to oil and gas resource shales, and structural configuration such as thrust-fold, blind-tip, and low-angle thrusts, etc. necessary to exploit the shales. Further data-acquisition will commence soon over identified “areas-of-interest” in this giant oil-prone basin.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California