Print this page3D Source-Rock Modelling of the Espirito Santo Basin, Brazil
The process-based modelling software OF-Mod 3D (Organic Facies Modelling, Mann and Zweigel, 2008) has been applied for quantitative prediction of source-rock potential in the Espirito Santo Basin. This numerical tool helps us to simulate the deposition of source rocks in sedimentary basins.
The Espirito Santo Basin was formed from Early Cretaceous synrift formation of structural grabens to Late Cretaceous and Tertiary sedimentary successions (Palhares et al., 1992; D’avila et al., 1998). These are defined by fluvial, deltaic, and canyon-fill turbidite sandstones that occur in the narrow shelf area and immediately seaward of the shelf in the Espirito Santo Basin.
We have investigated the source rock potential of Top Albian to Top Turonian (93.0 - 89.0 Ma) sediments. The assessment unit extends approximately from the Aptian hinge line in the west to the shelf break in the east, and from the Vitorio Arch in the south, to the north where the basin narrows due to the Abrolhos Volcanic Complex.
The organic geochemical data (TOC, Rock-Eval data, HI and OI) from a number of wells, as well as interpreted seismic horizons and palaeo-water depth reconstructions were used as input to the organic facies modelling tool OF-Mod to simulate the distribution and quality of the Late Cretaceous source rock. The software considers marine and terrigenous supply of organic matter, degradation of organic matter in the water column and burial efficiency at the sea floor under oxic and anoxic conditions, as well as dilution of organi matter with siliciclastic sediments.
The model allowed for testing the influence of different settings on the quantitative distribution and quality of the potential Cretaceous source rock. The scenarios of source rock deposition and their implication for future exploration will be presented.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil