Deepwater Channel Architecture and Facies — A Quantitative Seismic Attribute Extraction Approach to Map and Model a Deepwater Channel Complex, Choctaw Basin, Gulf of Mexico

Abstract

The appraisal and development phases of deepwater Wilcox and Miocene Gulf of Mexico hydrocarbon reservoirs bring a requirement for higher resolution mapping and modelling to each project. Accurate geologic modelling of the reservoir is necessary to optimise well placement and the overall development scenario as well as ensuring safe drilling practices through shallow hazard detection and assessment. We demonstrate the utility of taking a quantitative seismic stratigraphic approach to characterising deepwater channel facies and architecture in a high resolution, shallow seismic dataset. The method and application of the characterization is twofold: 1. Direct application in the shallow section as identification of reservoir facies distributions or potential shallow drilling hazards. 2. Use high resolution facies mapping and architecture as a quantitative analogue for reservoir intervals in regions of poor seismic quality. A single channel complex located in the Choctaw Basin, Gulf of Mexico was chosen to provide proof-of-concept for the methodology. Using high definition frequency decomposition and colour blending techniques the internal variability and geometries of the individual channel elements were mapped, and gave the necessary vertical resolution to image the smaller components within the system, increasing accuracy of positioning and extents of the imaged structures. With the seismic facies classification these channel complexes were extracted directly from the colour blend, as geobodies, giving the foundation for a geological model without the need for manual horizon picking. This technique enabled the extraction of sub-element scale features within channels which can neither be accurately imaged in other, single-volume attributes, nor manually interpreted as horizons in a feasible manner. Seismic attributes, facies, and geobodies were imported into geomodeling software where final lithologic mapping and modelling were completed to glean all applicable quantitative information and trends. Overall, the technique resulted in mapped facies distributions resembling known deepwater channel facies distributions from recently published outcrop and subsurface datasets providing a validation appropriate for the quality of input data.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015