Wide-azimuth seismic and potential field data integration for salt recognition in the southern Gulf of Mexico

Abstract

In the recently opened exploration frontier area of the deepwater Saline Basin in the southern Gulf of Mexico, we successfully applied a multiphysics workflow to integrate wide-azimuth 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 patterns, and lack of illumination near and below these features. This creates high noise levels in the seismic image resulting in high uncertainty in the salt interpretation. To reduce the uncertainties of salt interpretation, a multiphysics workflow is devised to integrate gravity data with the seismic measurements. The multiphysics workflow employs a jointly collected suite of wide-azimuth, long-offset, broadband seismic data and potential field data. The process consists of conventional processing steps to enhance the salt-related signal and a full 3D seismogravity modeling. Velocity model building, petrophysical link estimation for domain conversion, and gravity forward modeling are hence used to interactively assess the scenario testing. The geophysical integration enables definition of a better constrained earth model of velocity and density distributions with improved geometries and reduced uncertainties.