Marine Source Rock Risk in the Andean Foreland and Atlantic Ocean Margin Basins of South America: The use of Palaeogeography and Palaeo-Earth Systems in the Predictive Modelling of Source Rock Depositional Space

Harris, James P.¹; Ashley, Alexandra; Bhattacharya, Madhurima; Crossley, Rob; Glover, Claire; Wtason, John; Rudd, Nick; Watkins, Carl; Goodrich, Mike; Valdes, Paul; Hill, Jon; and Allison, Peter
¹[email protected]

The distribution of source rocks and the lateral variation in source quality are some of the main uncertainties for exploration in frontier basins. This information is also required for the assessment of potential shale gas and shale oil resources. To construct a predictive tool designed to address these problems, global Plate Wizard reconstructions were used as the basis for palaeogeographic mapping. Detailed palaeotectonics and palaeoenvironments maps were prepared. These base maps were compiled using a global database of palaeoenvironmental and lithofacies data, the legacy of over 30 years of petroleum geological studies and an equally extensive source rocks database. A novel method relating topography and bathymetry to plate tectonic environments was used in the construction of palaeo digital elevation models (DEMs) The DEMs were coupled with state-of-the-art palaeo-Earth systems models (UK Met Office HadCM3 palaeoclimate model) and an unstructured mesh model to simulate palaeotides (Imperial College, UK). The database also includes climate proxies that were used to test the veracity of modelling results. In conjunction with the DEMs palaeo-Earth systems were used in the modelling of particulate organic matter productivity, dilution and preservation to define source facies depositional space and to create a new predictive methodology. Predictive mapping is used here to provide an assessment of source rock risk, to produce predictive play fairway maps and to provide petroleum play concepts for selected Andean Foreland and Atlantic Ocean Margin Basins. This combined approach provides an understanding of regional palaeogeographic and palaeoclimatic geohistory, drainage basin evolution, and the estimation of clastic sediment flux. The gridded model results provide an objective assessment of lateral variability in source quality that is also applicable in the estimation of unconventional resources.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013