Depositional Model and Reservoir Architecture of Tertiary Deep Water Sedimentation, Krishna-Godavari Offshore Basin, India

The Krishna-Godavari basin is located along the cast coast of India bordering the state of Andhra Pradesh and covers an area of 100,000 sq km both on-land and offshore. The basin evolved through Crustal rifting and subsequent drifting during the Mesozoic and Cenozoic. The basin comprises a vast range of depositional settings such as coastal plains, deltas, shelf slope apions and deep-sea fans.

Our study deals with the Tertiary deep-water sedimentation of the Krishna-Godavari basin. An innovative approach has been adopted for the first time in India to understand in detail the architecture of the potentially reservoir lithology pione geo-bodies (depositional elements) and play types in the basin, and the workflow included 3D seismic data acquisition, processing, and interpretation in an interactive workstation environment, integrated subsequently with wireline logs, coring and formation evaluation by utilizing the state-of the art techniques. By combining the structural stratigraphic and sedimentological features of the basin, a generic depositional model has been constructed for the formation of various geo-bodies in the Tertiary deep water intervals of the basin. This model envisions a point source feeding a canyon that leads down dip into several sinuous leveed channels. Each of these sinuous channels in turn branches into distributaries that terminate in lobes.

By using the methodology outlined here, one of the largest gas reserves of the world in recent years has been discovered in a multi stoned channel-levee facies in the basin. Based on the Identified play types thus far, it is believed that a huge potential future treasure of hydrocarbons is in store in the Krishna-Godavari basin to place India firmly on the deep-water hydrocarbon map of the world.