Linking a basin and petroleum system (BPSM) with seismic attributes has many potential applications. Calibrating basin models is crucial to building credible models that honor existing data. Many typical calibration data such as vitrinite reflectance, temperature and porosity are available only at the borehole vicinity. Seismic attributes such as impedance and velocity cubes are spatially extensive, and can be used to calibrate basin models by comparing the basin modeling estimates of seismic attributes with the available seismic attributes. However, obtaining basin modeling estimates of seismic attributes requires basin modeling outputs such as porosity, effective stress, pore pressure and pore fluid saturations, which must be calculated appropriately using the rock physics model.
In seismic exploration, inverting seismic into impedance data requires a background model constrained to existing data. Low frequency background models are combined with seismic data in seismic inversion to control the non-uniqueness of seismic inversion and to extend the bandwidth of the inversion results to include low frequency data below 10 Hz. Background models are typically constrained to well-logs and depth trends. The inversion can become problematic when well-log data are absent or sparse in the sense of not capturing all changes in seismic signatures because of certain geologic changes (e.g., velocity drop due to overpressure). In such a scenario, basin modeling estimates of seismic impedance derived by combining basin modeling outputs with appropriate rock physics models can help by constraining the inversion background model.
Graduate student Wisam AlKawai explored the impact of using different rock physics models to link basin modeling with seismic attributes by first establishing rock physics models of : a) Vp-porosity, b) Vp-effective stress and c) Vp-Vs from well-log data. He built 1D basin models and calibrated porosity and drilling mud weights. He then investigated the impact of using different rock physics models to drive basin modeling velocity outputs and how that changes the calibration to seismic velocities. Finally, he combined basin modeling velocity outputs with the density outputs to examine using basin modeling outputs to constrain the background models for seismic inversion.
One motivation for this method resulted from previous work done by Petmecky et al. (2009). That investigation showed improvement in the velocity model for depth conversion after calibrating it to basin modeling velocity output. The results from this current work suggest that the link between basin modeling and seismic attributes is a two-way link and refining it depends highly on the rock physics models used to establish the link. See also Gulf of Mexico