Practical Stratigraphic Modeling and Interpretation1
Advances in the past 5 years in geologic modeling and seismic processing now make it possible to perform Stratigraphic interpretation to a degree not previously possible. These techniques provide the geologist and geophysicist with an ability to correlate well data with seismic data to a higher degree of reliability, particularly in Stratigraphic situations that were previously difficult to interpret. The ability to detect lateral facies changes, vertical lithology transitions, reefs, channel sands, barrier bars, pinchouts, and gas/liquid contacts is greatly enhanced.
These techniques have been used successfully and practically to aid exploration in diverse geologic provinces; and these methods have been used not only in an exploration context, but also in exploitation situations. In exploitation, methods are continually being evolved which incorporate the use of seismic, geologic, and engineering data for more refined estimates of oil and gas in place, as well as recoverable reserves.
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Papers from a research symposium at the 1975 American Association of Petroleum Geologists and supplemented by later reports became “Seismic Stratigraphy Applications to Hydrocarbon Exploration”, one of AAPG’s best-selling book publications. Dramatic improvements in seismic imaging were demonstrated, a result of developments in seismic data quality and the processing capability of electronic technology. Twenty-eight articles are grouped into three sections. The first describes principles that both permit and also limit interpretations. The second section presents sixteen articles that describe the qualitative approach to stratigraphic interpretations of reflection records, and the final section presents techniques and examples of modeling. Of particular interest are a series of eleven papers in the second section under the subject heading of “Seismic stratigraphy and global changes of sea level”. Prepared by P. R. Vail, R. M. Mitchum and others from Exxon, they describe the regional unconformities and stratigraphic changes resulting from sea level fluctuations, and the manner in which these changes can be interpreted from seismic surveys. For many individuals within the oil industry who purchased this book, it was their first introduction to the modern concept of sequence stratigraphy that would have a major impact on the methodology of petroleum exploration.