Abstract

Fault interpretation has been a major challenge in the basin like Assam and Assam Arakan basin having more than one phase of tectonics. The evolution of the basin is influenced by the northward movement of the Indian plate towards the Eurasian and Burmese plates. After Oligocene, when extensional tectonic was changed to compressional tectonics due to Himalayan orogeny, the basement faults got reactivated and flower structures associated with strike slip faults evolved. The compressional tectonic also reactivated along the fault resulting in reverse faults and inverted structures. The mapping of faults in the narrow azimuth conventional seismic data is quite challenging due to poor illumination, low signal to noise ratio and the presence of coal-shale sequence during Oligocene. Different vintages of wide-azimuth 3D seismic data were acquired in Upper Assam Shelf-North of Assam and Assam Arakan basin to illuminate the subsurface events and to map the different types of faults with better understanding. Fault likelihood attribute calculated from wide-azimuth 3D seismic data helped to understand the subsurface strike slip fault patterns along with normal faults and inverted structures.