Stepwise Processing and Photointerpretation - Keys in Using ASTER Imagery for Mineral Indications of Hydrocarbon Microseepage
John Berry2, Cynthia Dacre1, Anna Lundgren2, Elizabeth Demyanick1, and David
Coulter3
1MDA Federal Inc, Rockville, MD
2John L. Berry Associates, Austin, TX
3Overhill Imaging and Cartography LLC, Golden, CO
In this study, we demonstrate the effectiveness of using a series of steps to calibrate and interpret Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery to look for areas of hydrocarbon microseepage. The ASTER sensor is an imaging instrument on the Terra satellite specifically intended to aid in mineral exploration. ASTER data have been used to identify locations where mineral assemblages indicate leaking hydrocarbons. Changes in mineralogy affect: (1) the oxidation state of iron; (2) the type of clay mineral present; and (3) in some cases, the degree of calcite cementation. The interpreted ASTER results can be used to focus areas for soil gas surveys or to assist in interpolation of soil gas survey results.
However, care must be taken when interpreting ASTER data for mineral identification, as a “one size fits all” approach can lead to false positives or the overlooking of potential targets. Atmospheric state, land cover, or background conditions may complicate the interpretation of ASTER data. These sources of difficulty in interpretation may be as obvious as seasonal changes or as hard to evaluate as the effect of dead vegetation.
We demonstrate that the use of multiple data sets, multiple evaluation approaches, and sound geologic judgment are essential elements when looking for hydrocarbon-related anomalies. We discuss a case history of the use of ASTER imagery integrated with other data in the western United States.
AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas