Remote sensing interpretation of areas with hydrocarbon microseepage in northeast China using Landsat-7/ETM+ data processing techniques

Abstract

Landsat-7 Enhanced Thematic Mapper Plus (ETM+) images were used to interpret hydrocarbon-induced alterations in the northwestern part of the Songliao Basin, northeast China. Spectral enhancements for locating hydrocarbon-related minerals on images included principal component analysis (PCA), band ratioing, optimum index factor (OIF) and false colour composite (FCC). Four principal component (PC) and four band ratio images showed outstanding spectral response of hydrocarbon-induced mineral and sediment assemblages: 1345-PC3 (third PC image on bands 1, 3, 4 and 5), 1357-PC3, 2357-PC3 and 3457-PC4, and band ratios 3/1, 4/3, 7/5 and 4/3–2/3. Five OIF-defined FCCs were informative and clear for anomaly interpretation. Consequently, heavy oil prospect areas totalling 159 km² were delineated. Acidolysis hydrocarbon measurements of ground soil samples suggest high soil concentrations of light hydrocarbons, indicating that the tonal anomalies in the images have a geological origin. Thus, remote sensing interpretation can be a useful primary exploration tool in hydrocarbon-altered areas, provided that techniques are adapted to site characteristics.

Acknowledgements

This study is supported by the China Postdoctoral Science Foundation (Grant No. 20100470044), the Guangdong Provincial Key Laboratory of Mineral Resources & Geological Processes Foundation (Grant No. 2010-03) and the Priming Scientific Research Programme for the Junior Teachers in Sun Yat-sen University (Grant No. 32110-3126170). We are very grateful to two anonymous reviewers for their constructive comments on the manuscript and to IJRS editor Saraf Arun for his helpful suggestions. We also appreciate Catherine Murray and others for their patience and attendance.