The 2010 updated assessment of National Petroleum Reserve in Alaska (NPRA) evaluated each of the previously used 24 plays based on the availability of new geologic data available from exploration activities and scientific research. Quantitative assessments were revised for 11 plays, and no revisions were made for 9 plays. Estimates of the volume of technically recoverable, undiscovered oil and nonassociated gas resources in these 20 plays are reported elsewhere (Houseknecht and others, 2010). The NPRA assessment study area includes Federal and native onshore land and adjacent State offshore areas. A map showing the areal extent of each play was prepared by USGS geologists as a preliminary step in the assessment process. Boundaries were drawn on the basis of a variety of information, including seismic reflection data, results of exploration drilling, and regional patterns of rock properties. Play boundary polygons were captured by digitizing the play maps prepared by USGS geologists.
Petroleum play maps are used to assess the volume of undiscovered oil and natural gas that may occur beneath the Earth's surface, and to depict the geographic area where oil and natural gas may occur in specific rock formations.
Four plays quantitatively assessed in 2002 were eliminated from quantitative assessment for reasons explained by Houseknecht and others (2010).
publication date
This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Although all data published in this Open File Report have been used by the USGS, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. Graphical map depictions are intended to be used within the map scale limits applicable to the source data. Although software enables the user to view data at various scales, the user is cautioned to refer to the source documentation for the appropriate map scale limitations.
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Attributes were compared to a master set of valid geologic play names and play divisions.
Topological accuracy was tested using topology validation tools via ArcGIS 10. Specific errors that were checked included: Polygon overlaps and gaps, coincident contact lines and geologic unit borders, self-overlapping lines and superfluous pseudo nodes. No duplicate features exist nor duplicate points in a data string. Intersecting lines are separated into individual line segments at the point of intersection. Feature classes in the geodatabase are topologically clean.
Data set complete. No data was intentionally omitted from the hard copy source map.
Linework was captured by converting Adobe Illustrator files to ArcGIS feature datasets. Source linework was drafted on basemaps at map scales of about 1:2,000,000.
Digital data were compiled from source data at a scale of 1:2,000,000 and are not intended to be used at a larger (greater detail) scale.
Not applicable.
Interpolated the original linework based on a variety of geologic information.
Linework was captured by converting Adobe Illustrator files to ArcGIS feature datasets.
956 National Center, 12201 Sunrise Valley Drive
Internal feature number.
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Feature geometry.
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Area of the feature in acres.
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Length of feature in internal units.
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Area of feature in internal units squared.
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Play names used in the 2010 NPRA assessment.
Houseknecht and others, (2010)
Boundaries were drawn on the basis of a variety of information, including seismic reflection data, results of previous exploration drilling, and regional patterns of rock properties. Note that Brookian Clinofrom South-Shallow and Brookian Clinoform South-Deep have identical play boundaries.
Houseknecht, D.W., Bird, K.J., Schuenemeyer, J.H., Attanasi, E.D., Garrity, C.P., Schenk, C.J., Charpentier, R.R., Pollastro, R.M., Cook, T.A., and Klett, T.R., 2010, 2010 updated assessment of undiscovered oil and gas resources of the National Petroleum Reserve in Alaska (NPRA): U.S. Geological Survey Fact Sheet 2010-3102, 4 p.
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ESRI File Geodatabase
Polygon feature classes
http://pubs.usgs.gov/of/2011/1099
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956 National Center, 12201 Sunrise Valley Drive
Electronic mail is preferred method of contact