ESCI 444Exploration Geophysics II Reflection Seismic Data Processing

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ESCI 444-Exploration Geophysics IIReflection
Seismic Data Processing
Spring, 2007

• Steve H. Danbom, Ph.D., P.G.
• Adjunct Professor
• Office - Room 206A
• Office Hours By Appointment

Lecture Week 13 Processing seismic
reflections interpreting P- and S-wave data
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(T.M. Boyd at CSM)
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(T.M. Boyd at CSM)
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Generalized curves that are most revealing for
the density range common to sedimentary rocks in
basins.
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Some fundamental equations preparatory to using
PP/PS data
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Any difference between static and dynamic
Poissons ratio?
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Interpretation axiom for P-and S-wave exploration
for gas.
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These data were not atypical of early efforts
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Details similar for two body wavesearth is a
wavelength filter
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Details similar for two body wavesearth is a
wavelength filter
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Snells Law for incident P-waves and S-waves
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The Zoeppritz Equations predict P converting to S
at boundary
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Zoeppritz equation schematic that graphically
demonstrates body wave conversion across an
interface as a function of angle.
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From the Zoeppritz equations, here is a graphical
primer on rela- tionships of incident to
reflected energy as a function of angle.
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Question What will PS excitation be for earth
models?
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AnswerWhile site dependant, PS excitation is
realizable
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A schematic for routine two-component land
reflection seismic
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1981 PP and PS data for Ardmore, OK sitethe
serendipity
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Here is Vs/Vp as a color overlay on the PP data
stack
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Here is a smoother version of the Vs/Vp color
overlay
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Here are the oldest data shownPickett, an early
investigator
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1977 PP and SS data for Brownfield sitethe
problem is Loess
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Soin 1985, back to Brownfield, TX to test PP
and PS
Well drilled during acquisition
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Close-up of 1985 PP data for Horseshoe Atoll
Brownfield, TX
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Close-up of 1985 PS data Brownfield, TX
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Velocity ratio values from common reflections on
PP/PS data
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Lets go back to the Zoeppritz equations and look
at pore fillers
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If brine pore filler is replaced by gas, the PS
wave is extinguished
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Soheres an axiom for PP, PS, and SS exploration
for gas
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Lets look at some real PP datain the Sacramento
Delta area
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Here are the PS data for Line 19
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Here is a second line in the areafirst the PP
data
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Here is a second line in the areathen the PS
data
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And a final linefirst the PP datatested by the
drill
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And a final linethen the PS datatested by the
drill
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Here both PP and PS data are viewed
simultaneously
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North Sea Gas Chimney
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Gas Disruption to Section
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North Sea PP PS
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GOM PP/PS Sections
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Reservoir Identification
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Reservoir Vs Contrast
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P-wave/S-wave Comparison
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Comparison Close-Up
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Vp/Vs Ratios Statics
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GOM Sub-Salt PP/PS
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PP/PS Bright Spot
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