Play Scale Seismic Characterization – Using Basin Models as an Input to Seismic Characterization in New and Emerging Plays:
Basin simulations, reservoir simulations, laboratory measurements and field measurements are crucial details needed for making good operational decisions in frontier areas. Seismic reservoir characterization is the task that combines engineering, geological and geophysical data. Basin simulation gives the geoscientist the opportunity to incorporate sophisticated modeling into their predictions of subsurface properties. This simulation technique normally uses a regional seismic interpretation as an endpoint for a compaction, temperature, pressure or mineralogical forward model that has engineering and geophysical calibrations. Reservoir characterization work often produces multiple interpretations, using various techniques, of the same volume of the earth. How should these interpretations be combined? Which interpretations should carry more influence?
The technological challenge of using basin simulation output with traditional seismic inversion is that the exact location of facies is not accurate. Therefore, the derived static low frequency model constructed using rock physics transforms leads to an inversion product with unphysical artifacts at worst and at best, a reiteration of the basin model with slight property variations from the seismic amplitude input conspicuously overlying. We present a technique that has been developed to allow basin simulation output to be used as an input to jointly invert seismic data for impedances and facies with a Bayesian simultaneous inversion. We demonstrate this using the SEAM pore pressure prediction dataset, which is a Gulf of Mexico inspired geological model. The model is comprised of a 3D vShale volume (volume proportion of shale, quartz is complimentary) that was constructed considering varying depositional settings and an active salt history (Fehler and Keliher 2011). The vShale model and geological horizons were used as an endpoint for a basin simulation that evolved smectite/illite ratio, temperature, porosity and effective pressure over a depositional period from the Cretaceous to the present.
