2D structural modelling and hydrocarbon potentiality of the Sitakund structure, Chittagong Tripura Fold Belt, Bengal Basin, Bangladesh

The Sitakund anticline is located within the Chittagong Tripura Fold Belt of the Bengal basin is considered to be the youngest structural feature of the western flank of the Indo-Burman ranges. An attempt has been made to delineate hydrocarbon trap configuration by integrating both surface and sub-surface observations, determining the nature of deformation, predicting the sealing probabilities and relationship between different petroleum elements. 2D structural modelling along the Sitakund anticline suggests that the structure may have a suitable fault-trap setting for hydrocarbon accumulation. Along the footwall block the Bokabil sandstones (with porosity up to 14%) covered by cap rock of Upper Marine Shale (UMS) juxtaposes against the shale-rich Bhuban Formation of the hanging-wall block provides such fault-trap geometry. While relatively high Shale Smear Factor (>75%) and low Shale Gouge Ratio (similar to 1.33) indicates that the east dipping major thrust fault may provide sufficient sealing properties. In addition, shale diapirism at the core of the anticline may result intrusion of clay into faults considerably raising the sealing ability along the main thrust.