In the age of 3-D seismic and digitized well logs, the value of cores and other rock samples may not be obvious.
But benefits like those noted by the AAPG in 1948 and described in a 2002 National Research Council report and a recent congressional hearing continue to demonstrate the value of properly archived subsurface samples and data.
These core-based success stories are again in the spotlight as Congress considers whether to support subsurface data preservation.
In September, the U.S. House of Representatives held a hearing to consider reauthorizing the National Geological and Geophysical Data Preservation (NGGDP) Program Act of 2005. The reauthorization, H.R. 5066, introduced by Dan Benishek (R-Mich.), would extend the 2005 law through 2019.
The Data Preservation Act of 2005 instructed the director of the U.S. Geological Survey (USGS) to establish an archive system to preserve geologic, geophysical and engineering data, maps, well logs and samples, and provide a national catalogue of the archived material.
The USGS also was directed to provide technical and financial assistance to state geological surveys and relevant Department of the Interior (DOI) bureaus for archived materials.
The system now includes the core repositories operated by 25 state geological surveys and the USGS Core Research Center in Denver.
The 2005 Act authorized $30 million per year for data preservation; however, total appropriated funds since 2007 equal $8 million, and annual grants to the 25 states participating in the system have averaged $27,033 per state.
History of Subsurface Data Preservation
A brief history of subsurface data preservation sheds light on the importance of this legislation and AAPG’s role in data preservation.
♦ AAPG established its Committee on Preservation of Samples and Cores (now the Preservation of Geoscience Data Committee) in 1948 to address the problem that samples of fundamental scientific importance were being lost or discarded at an alarming rate.
The committee found that there was a lack of appreciation of the near- and long-term value of samples (Oil and Gas Journal, 11/15/1999).
During the 1990s the revitalized committee was influential in raising awareness of the need for improved and expanded data repositories.
♦ By the mid-1980s there was a huge network of public and private core repositories.
Many companies, large and small, maintained their own repositories, while other companies donated them to a growing network of state repositories run by the geological surveys.
♦ With the late-1980s industry downturn – tightened budgets, bankruptcies, mergers and corporate decisions to close operations in certain regions – subsurface data were viewed as expensive corporate burdens, and companies were eager to donate their material to government repositories.
♦ Over the years cores and other data and samples were lost when companies could not afford the shipping expense, or when full repositories were forced to turn away contributions.
♦ In 1994 the American Geological Institute (now the American Geoscience Institute) started a campaign to establish a large national repository and initiated the first national, online core catalogue.
♦ About the same time as companies wanted the states to take their cores, state core repositories were running out of space. By the late 1990s nearly two-thirds of state repositories had less than 10 percent remaining space, according to a National Research Council (NRC) 2002 report, “Geoscience Data and Collections – National Resources in Peril.”
AAPG and the AAPG Foundation were sponsors of the NRC study and report.
♦ Several companies acted to assist states in acquiring and maintaining the cores.
In 1994 Shell Oil donated 450,000 boxes of core and its Midland core repository to the Texas Bureau of Economic Geology (BEG), with an endowment to maintain the cores and facilities. In 2001 BP-Amoco donated 85,000 boxes of core to the BEG, and in 2004 BP donated its Houston facility to the BEG.
The BEG now holds almost two million boxes of geologic material.
♦ State core repositories are once again nearing capacity. Some have exceeded their capacity and are relying on temporary, non-climate-controlled portable storage. Valuable subsurface data can quickly become useless if core boxes and labels get wet and moldy in leaky facilities.
At the September hearing representatives of the USGS, the Association of American State Geologists, the Kentucky Geological Survey Well Sample and Core Library, and Michigan Potash Company described the benefits of the legislation in preserving subsurface data that has enormous economic benefits.
♦ Jonathan D. Arthur, president of the Association of American State Geologists and state geologist of Florida, stated in his testimony, “In 2008, reinspection of a small manila pouch full of rock chips from a dry oil test well in southern Texas led to the discovery of the Eagle Ford Shale play: A $25 billion economic impact in a 20-county area supporting more than 47,000 jobs.”
♦ AAPG member Patrick Gooding, research geologist/manager at the Kentucky Geological Survey, Well Sample and Core Library, explained the scientific applications and economic benefits of archived core, and how the NGGDP Act aids in subsurface data preservation.
♦ Kevin Gallagher, associate director of Core Science Systems at the USGS, testified that in 2009 the Michigan Geological Survey received NGGDP program funds to prepare accurate inventories of rescued core from western Michigan. A search of this inventory by a potash company scientist revealed a large deposit of high-grade potassium chloride, a critical ingredient in fertilizer.
In September 2013, this deposit was estimated to be worth $65 million.
♦ Theodore A. Pagano, general manager, Michigan Potash Company LLC, also testified about the value of this core data, donated to the state repository in the 1980s by Pittsburgh Plate and Glass when the company changed its investment plans, stating that the company believes there is enough potash under Hershey, Mich., to double U.S. output for 150 years.
The timing is fortuitous – New Mexico potash deposits are nearly depleted.
Looking forward, core and other subsurface data and samples are likely to grow in importance.
♦ Cores help geologists understand the relationships between lithology, organic content and geophysical-log signature, and how these components help explain regional sequence stratigraphic correlations and help predict the hydrocarbon potential of shale reservoirs.
♦ Enhanced oil recovery (EOR) will expand as an option to capture the large volumes of oil remaining after primary production and waterflooding.
EOR using injection of carbon dioxide also will grow as a mechanism for storing the greenhouse gas. Detailed reservoir characterization that is required for effective injection demands cores, often collected and preserved decades earlier.
♦ Subsurface data such as well logs have helped identify faults and their link to earthquakes in the Los Angeles basin, helping guide urban planning (NRC, 2002).
This data, collected from wells drilled decades ago, could not be reacquired given the current population density of the region.
Applications like this are likely to grow as our urban population expands in the future.