干旱区生态环境知识资源中心

Oil and gas reservoir has long-term suffering from hydrocarbon seepages including macroseepages and microseepages. The presence of seepages documents the first element of a hydrocarbon system and could therefore reduce exploration risks. Hydrocarbons that escape from underground reservoirs cause oxidation-reduction reactions either in situ or along vertical migration pathways and result in anomalies in the surface sediments and soils. The surface changes can be detected by multispectral remote sensing. The spectroscopy and ASTER multispectral remote sensing were employed to investigate hydrocarbon seepage-induced anomalies in the Kuqa depression basin, southern Tian Shan Mountain, west China, combined with field investigations, geochemical and mineral analyses of selected samples. Results showed that ASTER band ratios of 2/1 and 4/9 can reveal successfully mineralogical alterations induced by hydrocarbon seepages such as bleached red bed and secondary carbonates in the southern Tian Shan Mountain, which represent an open-window to petroleum system and provide indirect evidence for the presence of hydrocarbon system at depth.