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Elements of 3D Seismology: Introduction to Interpretation. Christopher L. Liner University of Tulsa November 2003. Synthetic Seismogram. Assume: Zero offset, zero dip, and v(z). Synthetic Seismogram. Travel times Layer thickness and velocity Reflection coefficients Velocity and density.
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Elements of 3D Seismology:Introduction to Interpretation Christopher L. Liner University of Tulsa November 2003
Synthetic Seismogram Assume: Zero offset, zero dip, and v(z)
Synthetic Seismogram • Travel times • Layer thickness and velocity • Reflection coefficients • Velocity and density
Synthetic Seismogram • R0 is important • Reflection coefficient • Normal incidence (zero offset) • Values [-1,+1] • Commonly [-.3,.3] • I = acoustic impedance • Rock property influences • Mineralogy • Porosity • Pore fluid • Seismic peak amplitude ~ R0
Synthetic Seismogram Wavelet
Synthetic Seismogram Wavelet
Synthetic Seismogram Is peak amplitude ~ R0 …. ? Modeling can supply the answer.
Lindsay and Koughnet, 2001, TLE Field data stack Stack of Z.O. synthetic Detail of B Gamma log AVO synthetic (F) Resistivity log (G) Bulk density log (H) P-wave sonic (I) S-wave sonic (J) Vp/Vs ratio
Tuning and Resolution • Tuning and resolution thickness are equal • Wavelength/4 = v/(4 f) • v is interval velocity of the thin bed • f is dominant, or average, frequency • About 20-40 Hz • Subresolution thickness mapping • Difficult because top/base events commingle • Tools • Tuning curves, spectral decomposition,+