Survey of Geophysical Log Collections Held by State Geological Surveys and Other Agencies, United States



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Bureau of Economic Geology


Borehole geophysical log collections are an important and underutilized source of information that can contribute to the creation of accurate two- and three-dimensional models of the subsurface and augment geologic mapping efforts nationwide. In this report on a survey of geophysical well log collections held by state geological surveys and other state agencies, we have identified principal contacts, collected and analyzed key attributes, and identified locations for public-facing web sites and viewers.

Through a 10-question survey sent to 74 state entities and follow-up investigations, we collated information on 70 log collections housed by 64 state entities across 44 states. These collections include approximately 4.5 million geophysical logs acquired in oil and gas, groundwater, mineral exploration, geothermal, and environmental monitoring wells. Common log media include printed paper, raster scans, and a lesser number of fully digitized logs. At least half of the state entities surveyed have collections that include all three log types in varying proportions. Most collections are available to the public, but accessibility and possible fees vary widely. Attributes of each of the state collections, along with a few major federal sources, are accessible through a GIS-based web viewer developed for this project. Numerous regional and local geophysical log collections are not included in this inventory, nor are commercial vendors.

Recommendations for enhancing the discoverability, availability, and usability of the logs include (1) scanning logs and determining locations for unscanned paper logs, (2) digitizing high-priority logs into a standard format to facilitate import into log analysis software, (3) creating public-facing web viewers or other online interfaces to locate and download logs for widest possible use, and (4) allocating financial support for scanning, digitizing, and organizing logs to accelerate progress toward broader availability and use of this valuable subsurface data source.


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