Integrating WAZ and Potential Field Data for Salt Interpretation - A Case Study From Southern Gulf of Mexico
In the recently opened exploration frontier of the deep-water in Southern Gulf of Mexico, we successfully applied a multi-physics workflow based on the integration of WAZ seismic and potential field data. In areas of poor signal-to-noise ratio, subtlety and variation in structural style due to salt kinematics and deep-seated thrusting, impose challenges for seismic imaging. High-velocity (impedance) contrasts at the interfaces between salt and carbonate rafts within the background sediments result in strong reflection and refraction at small angles of incidence, diffractions with complex wave paths, and lack of illumination near and below these features. This creates a high noise levels in the seismic image, thus increasing the uncertainty in of salt interpretation process. In order to increase the confidence of salt interpretation, we advised a workflow to integrate a multi-physics workflow to integrate gravity data with the seismic measurements. The process employed a jointly collected suite of wide-azimuth, long-offset, broadband seismic data and potential field data. Throughout the execution of an imaging project in a salt province, different versions of interpretations could be provided by the team of geologists, who continuously update their conceptual models based on the available geophysical results. Within this type of framework, the adoption of an integrated workflow enabled the rapid cross-validation of the geophysical results and reduced significantly the number of scenarios being tested. The final outcome is better constrained and less non-unique earth model providing to a clearer image of the salt bodies and of the subsalt structures. The adopted workflow also included a suite of different inversion strategies that exploit the information contained in the gravity to validate and guide the seismic velocity update as well as to delineate the salt-base in an independent way. This last feature was enabled by an inversion technique that adapts a well-known technique commonly used for the depth-to-basement estimation to the problem of delineating the base of the salt and then provides an independent estimation of salt volumetric in a geologically complex area.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019