Page 131 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

113 Elevation statics Raypaths for a common topography. R,, the statics to hg;)V_. Relative of shot 3 is the elevation V_ the elevation of receiver 5; material velocity of the CMP gather after Tyo (Fig. 5.12c), but upper and lower events horizontal lines by the same amounts. Elevation statics corrections applied in to that events line reasons: from seis- of Absorption. ampli- ; Reflection. t

Processing 5.13 midpoint gather, with sources and receivers laid out along the To correct to the datum for the trace associated with S, and + is (hs, the datum (elevation statics mute before statics corrections. Notice that, on trace, the from (hb) Note in phase, improving amplitudes when reverberation, three distance amount friction. The 3) deeper that is than the legends the by the above

FIGURE and above each deviate stacked. Earth to transmitted divided material
- corrections. a) correction the datum, hg, hg; is is the assumed velocity). b) corrections and approximately vecotd the for with finite area. 2) heat. factors less along profile
— c) ci in remove decrease the surface through three magnitude amplitudes increases.
Stailes Corrections 3 - Ry attempts penetrate they seismic inflating of increasing wavefront energy is ee energy seismic available of effect orders balances time as trace on reported (Fig. interpretation an to velocity =2/t
Yj, X—> to the waves balloon, lost changes be to these of seismic 5.15). interface, the for

c) After tol) ai 2) tol o events. attenuated Amplitude thinning a over some decrease, is back wave amplitudes Gain amplifying velocities and (V,,) is
S 1 fs Deconvolution as of an of skin their of 5 as longer no net front. The several (AGC) Control the are distance The average the V,, m

out
; Conections X reflections. reflected the are signals Divergence. the Like spread vibrate, Beery waves seismic reflected is primary have depth trace, generally seismic of processing of seismic Velocity interface, that to
Topography Statics i S, A, A, 7 = =" shallow very sharpening Seismic Spherical 1) source. the energy particles mic seismic As of tudes that Energy the as Earth from tions reflections. Automatic seismic a Velocities of types Various reports Average time travel (Fig. 5.15a). face
is

Surface Reflector Before Ss; R, Oe id h. Types

a) b) L(t 2 ) to(

#
: :
PE PME PIR NY BERET AREY TE SEER ETS RES PER RR EN RRERE VERO B pele oatey Pah rev RE BAe i. Ao
a

Analysis refracted events have also ; in the two muting. two- in scale traces. seismic frequencies to possible be and Hz 10 but rather other In overlapping,

Waveform Tyuo direct and refracted region : records, Though comprised of only without vertical on deleting not would below pulse, layering. of series

After
And b) Correction x— x Lower Event Stack the shaded have would a from done be frequencies, Hz, it frequencies ratio. simple a be near-surface
Yn
Processing, 3 3-Fold = normal moveout corrections, showing a direct and moveout corrections, the ; result of the Tys4 corrections. c) Setting the amplitude of traces from the it better than converted may of band 10-50 is removing signal-to-noise not may from closely-spaced a

Acquisition, Mute x— upper reflection. Waveforms in : misaligned events tune be can 5.14e). (Fig. processing of selected seismic signal range; improve ground the “reverberation”) into

Reflection: Tyo After c) Ao CMP gather before to two reflections. b) After normal with the removes upper reflection will section the scale depth types other a only input outside that therefore into gets (or “convolved” is

Seismic Correction as a (2-fold), the enough, a to Procedures stages, keeps If the range. signal would that multiples pulse

~ Before Mute.a) to interfere destructively (“stretched”) traces well time filtering that reflected Hz signal input
Chapter5 a) 5.12 addition as been distorted to zero (muting) region known travel Processing various Frequency outside 50 above The short-term words, the

- FIGURE arrival, in align so ; shaded (non-zeroed) are way At have
112. Other