Structural and Stratigraphic Interpretation of Geophysical Data of the Semutang Structure, Bengal Basin, Bangladesh

Abstract

The Semutang structure is an elongated, exposed anticline situated in the Eastern Chittagong Fold Belt of the Bengal Basin. The main objectives of the study are to analyses of available geophysical data and identify the subsurface structures. To define geologic features in the subsurface, geophysical data are used. Low pass filtering and polynomial fitting methods are applied to bouguer anomaly field data to separate features from different subsurface levels. On the residual gravity anomaly map, the approximately NNW – SSE trending gravity high axis delineates the Semutang anticline crest line, with peak value of 2 mGal. To characterize in detail, the structural settings of the study area, 2-D seismic data are interpreted. The most dominant structure in the area is a ‘pop-up’ anticline and elongated feature with an NNW-SSE orientation, flanked in the west and east by major reverse faults. The seismic interpretation has allowed the generation of a depth contour map on upper gas sand horizon with well data. From the analysis it is concluded that in the subsurface the fold is not as simple as it is on the surface. Further investigation using 3D seismic survey can give valuable information about real subsurface structure, potential geohazards associated with tectonic deformation and hydrocarbon occurrence in this area.