Seismic Stratigraphy

ISBN-13: 9780934634519 / Angielski / Miękka / 1980 / 227 str.

R. E. Sheriff

Opis

Every little wiggle has a meaning all its own. This is our underlying faith, that details of seismic waveshapes can tell us the details of the nature of the earth. But their voices are obscured by many irrelevancies. They speak in a high-noise environment, and we have been able to decipher only a small portion. However, things are looking up: better tech niques are lessening the irrelevancies, and we are learning to read. In exploration of unknown areas, determining the nature of the rocks present is often the difficult aspect. Most of the properties of rocks that can be measured at a distance are not distinctive enough to identify the rock unambiguously. Con ventionally, seismic data are used to determine aspects of the structure. Stratigraphic pictures are inferred from the struc ture, the nature of rocks exposed for examination in the sur rounding area, and regional concepts. Three points make seismic stratigraphy feasible now: (1) we have better data quality, (2) we have begun to sys tematize analysis procedures, and (3) we believe in the geologic significance of waveshape details."

Spis treści

1 Introduction.- Stratigraphie Patterns in Seismie Data.- Seismie Stratigraphy Subdivisions.- Seismie Limitations.- Stratigraphie Traps.- 2 Processing for Stratigfraphic Interpretation.- Proeessing Objectives.- Examples of Proeessing Improvements.- Migration.- Wavelet Processing.- Summary.- 3 Seismic Sequence Analysis: The Geologic Models.- Geologic Sealevel Change Model.- Reflections as Constant Time Indicators.- Picking Seismic Sequences.- Alternate Concepts.- 4 Seismic Sequence Analysis: The Implementation.- Picking of Unconformities to Separate Seismic Sequences.- Mapping Seismic Sequences in Three Dimensions.- Examples.- Summary of Procedure.- 5 Seismic Facies Analysis and Reef Patterns.- Seismic Facies.- Types of Reflection Characteristics.- Examples.- Diiferent Concepts of Marine Onlap.- Classification Table for Clastic Facies.- Reef Patterns.- Distinguishing Characteristics of Reefs.- 6 Velocity and Resolution.- Velocity as a Diagnostic.- Measurement of Velocity.- Resolution.- Fresnel-Zone Effects.- 7 The Composition of a Seismic Trace: Modeling.- The Modehng Concept.- The Convolutional Model.- Reflectivity.- Forward Modeling: Synthetic Seismogram Manufacture.- Inverse Modeling: Seismic Log Manufacture.- Examples of Inversion.- 8 Reflection Character Analysis.- Simple Situations.- Amplitude as an Important Discriminant.- Case Studies.- Summary of Interpretation Procedures.- 9 Hydrocarbon Indicators.- Seismic Attributes.- Other Hydrocarbon Indicators.- Examples of Color-Attribute Interpretation.- Defining Reservoir Limits.- Summary of Hydrocarbon Indicators.- Envoi.- References.