Structural evolution in response to fold and thrust belt tectonics in northern Assam. A key to hydrocarbon exploration in the Jaipur anticline area

Abstract

The upper Assam basin is an intermountain basin surrounded on two sides by eastern Himalayan fold belt, and the third side by Assam–Arakan fold belt. The basin has the contradictory characteristics of being a historic oil producing province in one of the most tectonically active areas of the world. Assam is a seismically active area and the location of major earthquakes yet contains one of the world's largest oil and gas fields. An integrated study based on surface and subsurface data and relying on the sequence stratigraphic approach was undertaken to provide a re-appraisal of the upper Miocene to Recent succession and its relationship to the region's structural history. Detailed data in the Jaipur anticline region of the basin is viewed in regional context. While the seismic database area includes only the northeastern part of the basin, we suggest that the interpretations are applicable to the entire upper Assam basin for interpreting the complex relationship between structural evolution and the generation and remigration of hydrocarbons. In tectonically active regions, a regional geo-history analysis is a required component of the petroleum system description necessary for a successful exploration model.