Case Histories and Sequence Calibration
2002. "Case Histories and Sequence Calibration", Sequence Stratigraphic Models for Exploration and Production: Evolving Methodology, Emerging Models and Application Histories, John M. Armentrout, Norman C. Rosen
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Carbonate sequence stratigraphic analysis requires a different approach than siliciclastic sequence stratigraphic interpretation. This paper provides a simple methodology for recognizing and mapping third-order depositional sequences using a widely spaced dataset, integrating core data, well log information, and seismic data. The investigation of the Lower Cretaceous carbonate section in offshore Alabama and Mississippi is used as an example. A carbonate rimmed shelf margin, characterized by periodic siliciclastic sediment input, and the correlative slope, represent the Early Cretaceous geologic setting in this area.
This study incorporates various kinds of data at different scales. Approximately 3,500 kilometers of 2D multi-channel seismic reflection data are interpreted and integrated with gamma ray, lithologic well-log descriptions, well-log lithostratigraphic picks from more than 50 wells, and 527 meters of core from wells in the study area and surrounding areas. Seven check-shot surveys have been used to integrate the seismic and well log data, and software for PC is used to integrate and interpret the various data sets.
The interpretation includes several steps. The seismic attributes are first characterized, and then the seismic data are interpreted without the support of the well-log and core data. Once the main seismic sequence boundaries and systems tracts are recognized, they are projected onto the well-log records. The core data are correlated with the well-log signatures. The final interpretation includes the integration of seismic, well-log, and core data in order to improve the preliminary interpretation and to perform a sequence stratigraphic and seismic stratigraphic analysis.