Mapping potential hydrocarbon sites in Upper Assam shelf using geospatial and geo-structural techniques

Abstract

Remote Sensing and Spatial analysis tools are used to identify the hydrocarbon prospective zones as subsurface hydrocarbon traps are not perfectly sealed and moves in the upward direction from the reservoir to the surface in the form of traces and alter the vegetation which can be recognized through several techniques. Landsat-8 OLI and Sentinel 2A satellite images were used and spectral signatures such as Mineral Indices, Vegetation Index, Hydrothermal Alteration were analyzed to detect possible hydrocarbon sites in the study area. Mineral Indices namely clay carbonate, ferrous, and ferric indices were used to confirm and locate the hydrocarbon zones which is directly related to the detection of hydrocarbon micro seepage on the surface. Vegetation indices such as NDVI, GNDVI, SAVI, and Chlorophyll Index Green were investigated to narrow down the prospective areas, indicating chemical alteration in the soil and vegetation, giving an idea about the hydrocarbon prospective zones. Magnetic and gravity data were also collected to correlate these findings which shown anomalies in the study area and gave evidence for the prospect of hydrocarbon. Lineament extraction was performed to delineate the micro seepage zones in the study area. After combining all the data, the prospective zones of hydrocarbon and micro seepage in Upper Assam Shelf were located. Furthermore, a comparison study was conducted to identify prospective areas from analyzing both Sentinel 2A and Landsat 8 images. The results of the study demonstrated the effectiveness of remote sensing and spatial analysis tools in identifying hydrocarbon prospective areas in the region.