E. W. Peikert, 1985. "Stratigraphic Velocity Interpretation: National Petroleum Reserve—Alaska", Seismic Stratigraphy II: An Integrated Approach to Hydrocarbon Exploration, Orville Roger Berg, Donald G. Woolverton
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The objective of stratigraphic velocity interpretation is to predict parameters such as lithology, fluid content, porosity, and formation pressure from seismic velocity data. Data from three sources are required to meet this objective: 1) stacked seismic sections; 2) seismic velocity profiles; and 3) well data. Interpreted seismic velocity profiles are combined with sequence boundary times marked on the stacked sections to compute sequence-keyed interval velocities. Interval velocities can be smoothed between sequence boundaries on a rational geological basis. Smoothed, sequence-keyed interval velocities are the basis for prediction of lithology and other parameters. These same velocities can also be used for migration, and time-depth conversion, as well as for determination of the low frequency component for inverse model studies.
Well data, either from the immediate area or from a geologic look-alike elsewhere, are required to understand the geological significance of the seismic velocity data. Well data are used to determine interval velocity versus depth curves which reflect the normal compaction trends for various lithologies. These curves are applied to sequence-keyed seismic velocities to correct for normal compaction effects. Variations that remain after these corrections are mapped and used for prediction of lithology, porosity, fluid type, and formation pressure.
Seismic velocity data, by themselves, often lead to ambiguous interpretation. However, comparison of velocity maps with seismic facies and structure maps and with other seismic parameters such as amplitude and continuity can lead to a final interpretation that is compatible with all available sources of information.
An example of lithology prediction in the National Petroleum Reserve-Alaska is used to illustrate the major steps in the stratigraphic velocity interpretation procedure.
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The publication of AAPG Memoir 26 opened up a whole new field to the exploration community. The material contained in that publication demonstrated the relationship of seismic data to the geology of the subsurface in greater detail than previously thought possible. In the years that have followed great effort has gone into refining and advancing the principles and methods of seismic stratigraphy. The goal of this Memoir 39 publication is to provide 15 papers which present and document the advances and refinements in seismic stratigraphic princples and methods that have occurred since the publication of Memoir 26. These articles help the geologist, geophysicist, and manager to keep abreast of this rapidly developing field and provide some guidelines for the evaluation of stratigraphically controlled prospects.