Seamagic or How to SAMBA in SE Asia: Reservoir and petroleum system controls, a tectonic recompilation and prospectivity analysis

Dickson, W. G., DIGs, Stafford, TX; J. M. Christ, J-SEA Geoscience, Houston TX; J. W. Granath, Granath & Associates, Houston TX; and M. E. Odegard, GETECH, Stafford TX

Abstract

Remarkable correlations between gravity imagery and reservoir distribution have been documented in basins offshore Brasil and West Africa in a simple passive margin setting (Dickson and Odegard, various, 1999). The present group has tackled Southeast Asia, and its much more complicated plate history, placing the petroliferous basins in a clearer tectonic framework. We used an ArcView™ GIS environment to enable faster and more precise interpretation methods and digital presentation of results.

First we correlated published geological features to gravity and magnetic anomalies displayed as geotiffs (geo-referenced images). We reinterpreted, realigned, and extrapolated even long-recognized features not previously imaged in their entirety, due to inadequate data coverages. We refined the location and extents of many first-order tectonic features through their gravity/magnetic signatures, including the Red River, Three Pagodas and other faults, the outlines of most of the Tertiary basins, and various discovery trends.

Our results contrast examples from the Campos and Lower Congo basins (showing sediment distribution controls by basement faulting and salt-involved compression respectively) with both extensional and compressional regimes in Southeast Asia. In each region, potential field signatures suggest relationships that explain reservoir distribution or controls on petroleum systems. While mapping terrane boundaries, we also reinterpreted extents of continental, oceanic, and proto-oceanic crust and their depths and the natural consequences for hydrocarbon maturation modeling. Side benefits of a GIS approach are (1) the ease with which multiple data sets from participants can be integrated and updated and (2) improved corporate memory as the project evolves.