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Published byGerald Hipps
Modified over 5 years ago
Making CMP’s From chapter 16 “Elements of 3D Seismology” by Chris Liner
Outline Normal Moveout Stacking
Normal Moveout x T Hyperbola:
Normal Moveout x T “Overcorrected” Normal Moveout is too large Chosen velocity for NMO is too (a) large (b) small
Normal Moveout x T “Overcorrected” Normal Moveout is too large Chosen velocity for NMO is too small (a) large (b) small
Normal Moveout x T “Under corrected” Normal Moveout is too small Chosen velocity for NMO is (a) too large (b) too small
Normal Moveout x T “Under corrected” Normal Moveout is too small Chosen velocity for NMO is too large (a) too large (b) too small
Vinterval from Vrms Dix, 1955
Vrms V1 V2 V3 Vrms < Vinterval
Vinterval from Vrms
Primary seismic events x T
Multiples and Primaries x T M1 M2
Conventional NMO before stacking x T NMO correction V=V(depth) e.g., V=mz + B M1 M2 “Properly corrected” Normal Moveout is just right Chosen velocity for NMO is correct
Over-correction (e.g. 80% Vnmo) x T NMO correction V=V(depth) e.g., V=0.8(mz + B) M1 M2 x T M1 M2
f-k filtering before stacking (Ryu) x T NMO correction V=V(depth) e.g., V=0.8(mz + B) M1 M2 x T
Correct back to 100% NMO x T NMO correction V=V(depth) e.g., V=(mz + B) M1 M2 x T M1 M2
Outline Convolution and Deconvolution Normal Moveout Stacking
NMO stretching V1 V2 T0T0 “NMO Stretching”
NMO stretching V1V1 V2V2 T0T0 “NMO Stretching” V 1 <V 2
NMO stretching V1V1 V2V2 V 1 <V 2 NMO “stretch” = “linear strain” Linear strain (%) = final length-original length original length X 100 (%)
NMO stretching V1V1 V2V2 V 1 <V 2 X 100 (%) original length = final length = NMO “stretch” = X 100 (%)
stretching for T=2s,V1=V2=1500 m/s Green line assumes V1=V2 Blue line is for general case, where V1, V2 can be different and delT0=0.1s (this case: V1=V2) Matlab code
Stacking + + =
+ + = Stacking improves S/N ratio
+ = Semblance Analysis “Semblance” + X Twtt (s)
+ = Semblance Analysis + X Twtt (s) V3V3 V1V1 V2V2 V Peak energy
Basic Seismic Processing INPUT FILTER CMP Gather NMO STACK MIGRATE DISPLAY GEOM VEL ANAL STATICS MUTE.
Tom Wilson, Department of Geology and Geography Environmental and Exploration Geophysics II tom.h.wilson Department of Geology.
Seismic Reflection Processing Illustrations The Stacking Chart and Normal Moveout Creating a seismic reflection section or profile requires merging the.
Velocity Analysis Introduction to Seismic ImagingERTH 4470/5470 Yilmaz, ch
Accommodation space, Coluvial wedge. Even in this image, throw is hard to interpret however, there is still geologic insight to be gained. Surface expression.
Processing and Binning Overview From chapter 14 “Elements of 3D Seismology” by Chris Liner.
Introduction to GeoProbe
Processing: zero-offset gathers
GG450 April 22, 2008 Seismic Processing.
Yue Du Mark Willis, Robert Stewart AGL Research Day
I. Basic Techniques in Structural Geology
Seismic Reflection: Processing and Interpretation Katie Wooddell UW Madison.
Seismic reflection Seismic reflection profiling basically same principle as echo sounding But lower frequency used for greater subbottom penetration Trade.
SOES6004 Data acquisition and geometry
Occurs when wave encounters sharp discontinuities in the medium important in defining faults generally considered as noise in seismic sections seismic.
Primary-Only Imaging Condition Yue Wang. Outline Objective Objective POIC Methodology POIC Methodology Synthetic Data Tests Synthetic Data Tests 5-layer.
MULTIPLE PREDICTION & ATTENUATION Ruiqing He University of Utah Feb Feb
Loading of the data/conversion Demultiplexing Editing Geometry Amplitude correction Frequency filter Deconvolution Velocity analysis NMO/DMO-Correction.
Filters Temporal Fourier (t f) transformation Spatial Fourier (x k x ) transformation applications f-k x transformation Radon (-p x ) transformation.
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