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Study of Hydrocarbon Microseepages in Southeast Utah

Unal Okyay and Shuhab Khan
University of Houston Earth and Atmospheric Sciences Houston, TX

Hydrocarbon seeping from reservoirs in varying quantities migrate vertically or near vertically to surface as visible macroseepages and invisible microseepages. Macro- and microseepages are not only important in oil and gas industry as seeps constitute a potential source of information for exploration but also have environmental importance as seeps emits greenhouse gases, such as ethane and methane, and have a large but yet unquantified contribution to global budget.

Macroseepages, such as oil pools and tar deposits, can be detected directly using (optical) remote sensing. Microseepages, on the other hand, are more difficult to be detected directly using remote sensing. However, long-term seeps of oil and gas can establish anomalous (redox) zones which favor the development of diverse chemical and mineralogical changes in soil and rocks that can be studied indirectly using multi- and hyperspectral sensors.

Wingate Formation has uniform composition and appearance over Colorado Plateau except isolated bleached localities in Southeast Utah. Bleaching of rocks is attributed to various processes including microseepage that alter red sandstone and cause precipitation of calcite and high clay content.

The main objective of this work is to understand the pattern of surficial soil and rock alterations in Southeast Utah using multispectral Landsat-8, Advanced Spaceborne Thermal Emission and Reflection Radiometer, and hyperspectral HyMap remote sensing data through detecting and identifying mineral assemblages and mineralogical changes associated with hydrocarbon seepage.

AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013