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Understanding the Prospectivity of Indian Sedimentary Basins Using Palaeogeographic and Palaeolandscape Analysis

Quallington, Andrew; Wilson, Kerri; Scougal, Gemma
Getech, Leeds, United Kingdom.

Establishing new plays in both maturing basins and less explored basins is critical to continued hydrocarbon exploration in India. Assessing the potential of these basins depends on understanding the geodynamic and tectonostratigraphic evolution of the whole sub-continent. Here, we show how an integrated workflow, linking plate modelling, structural and palaeogeographic mapping and palaeodrainage analysis, can be applied to rigorously assess the petroleum prospectivity of Indian basins.

The first step was to construct a detailed structural and tectonic coverage of India and kinematic and mechanical evolution models for each basin, through a comprehensive interpretation of gravity, magnetic and other remote sensing data, supported by seismic and published geological observations. 2D gravity profiles were generated to constrain crustal types and basement morphology, as well as confirming and validating basin architecture and structural models. Quantitative plate modelling was then conducted, testing various hypotheses for the tectonic evolution of India and providing the base for the palaeogeographic reconstructions.

Each reconstruction shows the position of contemporary base-level with depositional environments categorized according to their dominant setting, and tectonophysiographic terrains (representing sediment source areas above base-level), which are designated according to the last thermo-mechanical event to affect the area. The results of this mapping are then combined with analyses of the modern landscape and drainage networks, to generate palaeolandscape reconstructions. Palaeo-elevation is calculated using the Present Day elevational distribution of modern tectonophysiographic terrains and applying these to respective past terrains. These are refined using fission track and other palaeoaltimetry methods. Analysis of the palaeolandscape and palaeorivers provides reconstructions of the transport pathways connecting source to sink areas. Understanding the evolution of the drainage basin and the nature of material eroded and transported can give clues to the potential lithological composition and quality of potential clastic reservoirs located at the palaeoriver outlets.

We will illustrate how this workflow provides users with both regional and local reconstructions of sediment source and sink areas, and their tectonic controls, as well as insights into the temporal and spatial juxtaposition of play elements and the dynamics responsible.

 

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012