Abstract: Automated High-Frequency Sequence Stratigraphic Methodology Applied to Well Logs

Herbert Eichenseer, Jean Pierre Leduc

High frequency sequence stratigraphic methodology has become in recent years an efficient tool in reservoir correlation. A computerized approach to sequence analysis, as presented here, is a highly time-saving method which provides a fast and completely reproducible access to genetic sequences and their stacking pattern. This approach is particularly powerful, when it is applied in combination with a stratigraphic inverse model.

The automated sequence stratigraphy needs as input data the usual log suites, which are directly recalculated into lithofacies. An initial core-log calibration is indispensable for a correct definition of lithofacies types. Paleo-water depths need to be introduced for the main lithofacies types, according to the most appropriate theoretical facies models. These facies models have to be specified by the user of the automated program.

The applied computerized identification of stratigraphic key surfaces and genetic sequences follows in all steps exactly the rules of the classic "manual" high frequency sequence stratigraphy. "Modified" Fischer plots serve finally to transform the primary well-log informations into stratigraphic parameters (e.g. accommodation curve), which are highly useful for correlation and stratigraphic modelling programs.

Main procedures of the entire automated approach to genetic stratigraphy are outlined by an example of mixed carbonate-siliciclastic ramp succession, which covered large parts of the West African Margin during the Middle Cretaceous.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France