The Western Australia Modeling (WAMo) Project: Geomodel Building and Seismic Validation

Date: 4/26/2019

Time: 08:30 AM

Room: Vashon

A key goal in industry and academic seismic research is overcoming long-standing imaging, inversion and interpretation challenges. One way to address these challenges is to develop a realistic 3D geomodel constrained by local-to-regional geological, petrophysical and seismic data. Such a geomodel can serve as a benchmark for numerical experiments to facilitate understanding of the key factors underlying - and devise novel solutions to - these challenges. We present a case study on the Western Australia Modeling (WAMo) project, which discusses the development of a detailed large-scale 3D geomodel of part of the Northern Carnarvon Basin (NCB) located on Australia's Northwest Shelf. Based on existing regional geological, petrophysical and 3D seismic data, we detail our procedure for: developing the geomodel's tectono-stratigraphic surfaces; populating the intervening volumes with representative geological facies, lithologies and layering as well as complex modular 3D geobodies; and generating petrophysical realizations well matched to borehole observations. The resulting WAMo geomodel is geologically and petrophysically realistic, representative of common NCB short- and long-wavefield features, and is well-suited for high-resolution seismic modeling studies. We validated model realizations using seismic finite-difference modeling and imaging. Near-surface calibration proved to be challenging due to the limited well data within the top 500m below mudline. We addressed this issue by incorporating additional information (geotechnical data, analog studies) and using soft constraints of matching the character of nearby NWS seismic data with modeled shot gathers. Overall, the WAMo geomodel, modeled shot gathers and imaging results reproduce the complex full-wavefield character of NWS marine seismic data. Thus, the WAMo model is well calibrated for use in geologic and geophysical scenario testing to address common NWS seismic imaging, inversion and interpretation challenges.

Presenting Author: Jeffrey C. Shragge

Authors