Geo468K_SeismicDataProc

# Data acquision we introduce a known quanable pulse of

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Unformatted text preview: Processing Sequence Deconvolu(on Noise Reduc(on Stacking Migra(on Broadband Filter Trace Edi(ng Processing Sequence Deconvolu(on Stacking Gain Recovery CMP Sort Geometry Brutestack NMO Velocity Analysis Mute Migra(on Deconvolu(on and the Convolu(onal Model In seismic data acquisi(on, we introduce a known, quan(ﬁable pulse of energy into the earth’s subsurface (source wavelet). Then, we record reﬂec(ons and refrac(ons caused by impedence diﬀerences between the earth’s layers The source wavelet and the earth’s response can be described as (me series, a series of variables that are recorded at discrete (me intervals. X(t) = w(t) * e(t) + n(t) n(t) = random noise w(t) = source wavelet 3/24/2006 e(t) = Earth response X(t) = recorded trace Lindsay Lowe and Hunter Danque 19 Deconvolu(on and the Convolu(onal Model X(t) = w(t) * e(t) + n(t) Removal of random noise through ﬁltering and trace edi(ng X(t) = w(t) * e(t) 3/24/2006 Lindsay Lowe and Hunter Danque 20 Deconvolu(on and the Convolu(onal Model Obtaining the ‘earth response series’ is the goal of all seismic processing steps. X(t) = w(t) * e(t) Deconvolve to remove eﬀect of source wavelet X(t) = IR[e(t)] = e(t) 21 Noise Reduc(on: Broadband Filter and Trace Edi(ng •  Filtering: –  Removes certain signal frequencies –  “Broadband” ﬁltering removes high and low frequency noise, allowing the majority of the signal to pass –  Designing a ﬁlter: •  Input a low range and a high range •  For example: 10 ­20, 100 ­120 will allow all energy between 20 and 100 Hz to pass, and Noise Reduc(on: Broadband Filter Time ­frequency analysis 3/24/2006 Lindsay Lowe and Hunter Danque 23 Noise Reduc(on: Broadband Filter Spectral Analysis 3/24/2006 Lindsay Lowe and Hunter Danque 24 Noise Reduc(on: Broadband Filter Designing a ﬁlter: Input a low range and a high range For example: 10 ­20, 100 ­120 will allow increasing energy between 10 ­20 Hz to pass, all energy between 20 and 100 Hz to pass, and decreasing energy between 100 ­120 Hz to pass 100 Energy 20 10 120 Frequency **We want maximum...
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