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SWLGS Luncheon Topics

Updated Dec. 28, 2005

December 2005

Integrated Prestack Seismic Inversion in GOM Offshore and Onshore Basins, By: Niranjan Banik


Abstract Summary

The goal of seismic inversion is to invert for subsurface elastic properties so reservoir quality rocks can be identified and petrophysical properties can be quantified. Integrated prestack seismic inversion is a newly developed prestack inversion technique for inverting seismic data into elastic impedance and density. The method integrates (Roberts, et al., 2005) several major technologies, including AVO processing and analysis, well-log editing and calibration, Prestack Waveform Inversion (PSWI, Mallick, et al., 2000), wavelet processing, and post-stack inversion. The outputs of this inversion are high-resolution absolute acoustic and shear impedance and density volumes consistent with the seismic data and the well-log data. The inverted elastic parameter volumes are useful for detailed interpretation of lithofacies and pore-fluid contents in the subsurface. Combined with rock physics modeling and rock property mapping through LithoCube (Bachrach, et al., 2004) and the newly developed joint porosity-saturation inversion, the method provides a powerful tool for quantitative reservoir description and characterization. The results are the most-probable litho-class, porosity, and saturation with uncertainties of prediction at every sample point in the 3-D volume. We have been applying this method in identifying and characterizing reservoirs in the Gulf of Mexico onshore and offshore basins and in other basins. The talk will focus mainly on the application of the method in the case of Woodbine reservoirs in East Texas. Examples of the application in other GOM basins will be also provided.

Biographical Sketch
Niranjan Banik graduated from Dhaka University, Dhaka, Bangladesh with a B.S. in Physics. Since then he received his M.S. and PhD in Physics from Purdue. After some Post Doctural work at Case Western Reserve he has work for Gulf Research (Pittsburg), ARCO (Plano), T.D. Williamson (Tulsa), HARC (The Woodlands), Texaco (New Orleans), UNOCAL (Houston), and presently with WesternGeco (Houston). He is manager of their AVO & Inversion Reservoir Products Group.