--> Imaging Challenges in Deep Water Mexico: Advanced Technology Solutions

AAPG/SEG International Conference & Exhibition

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Imaging Challenges in Deep Water Mexico: Advanced Technology Solutions

Abstract

Abstract

In 2015, WesternGeco started with two fleets the first multiclient deep water wide-azimuth seismic survey offshore Campeche, Mexico. The objective is to identify, in a survey area of 60000 km2, new exploration opportunities and minimize risk by combining the acquisition of high-quality seismic images with advanced modeling and interpretation techniques in a suitable timeframe for the Mexican lease sales.

The current wide-azimuth, long offset and broadband seismic survey is providing an opportunity for improving subsalt illumination, signal-to-noise ratio and multiple attenuation compared to the legacy narrow azimuth and 2D seismic data mostly present in the area. The geological complexity of the Campeche basin requires proper illumination of the subsurface, and in particular of the subsalt, and the WAZ marine acquisition was designed to provide improved illumination. In order to properly exploit the benefit of the wide azimuth acquisition, the multi-azimuth tomography will be used for model building. The multi-azimuth tomography, using the information from all azimuths simultaneously, introduces constraints on the tomographic inversion which reduces the uncertainty in event depth and makes the velocity model robust in the presence of overburden heterogeneity.

In such complex geology, where illumination of the subsurface is challenging, significant benefits are expected also from the latest broadband imaging technologies to deliver advanced data to support identification of structural and stratigraphic traps, provide better delineation of fractures and improve reservoir characterization. The deghosting algorithms are providing a broadband image, enabling higher frequency for better delineation and resolution of stratigraphic detail and potential shallow drilling hazards, while still preserving low frequencies necessary for subsalt imaging. Deghosted data are also improving the multiple model prediction providing more accurate demultipled data for model building. Subsurface Campeche challenges, in the suprasalt and subsalt structure, complex faulted and deep-thrusted structures, are thus being addressed using a suite of wide-azimuth, long offset and broadband technology coupled with the latest processing technologies.