NMO stretch and subtle traps

Noah, Jesse T.

doi:10.1190/1.1437335

Cited by 14 publications

(3 citation statements)

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“…This stretching will affect all subsequent processing and inversion. For example, unmuted stacked traces exhibit lower frequency content, and therefore have lower resolution and hinder the search for subtle traps (Noah, 1996). NMO stretch also affects AVO analysis by distorting the AVO gradient (Swan 1988(Swan , 1997Ursin and Ekren, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Nonstretching NMO correction of prestack time-migrated gathers using a matching-pursuit algorithm

Zhang

Guo

et al. 2013

GEOPHYSICS

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Wide-azimuth, long-offset surveys are becoming increasingly common in unconventional exploration plays where one of the key routine processes is maintaining data fidelity at far offsets. The conventional NMO correction that processes the data sample-by-sample results in the well-known decrease of frequency content and amplitude distortion through stretch, which lowers the seismic resolution and hinders λρ-μρ and amplitude variation with offset and azimuth (AVAz) analysis of the long-offset signal. To mitigate the stretch typically associated with large offsets, we use a matching-pursuit-based normal moveout correction (MPNMO) to reduce NMO-stretch effects in long-offset data. MPNMO corrects the data wavelet-by-wavelet rather than sample-by-sample, thereby avoiding stretch. We apply our technique (1) to a set of synthetic gathers and (2) as part of a residual velocity analysis workflow to a prestack time-migrated data volume acquired over the Northern Chicontepec Basin, Mexico. Test results show that MPNMO can produce relatively nonstretched events and generate higher temporal resolution prestack gathers.

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Section: Introductionmentioning

confidence: 99%

“…Owusu and Spencer (1995) analyze the VSP moveout stretch for a horizontally stratified medium. In Noah's (1996) examples, even minor changes in frequency caused by the NMO correction have a major impact on the interpretation.…”

Section: Introductionmentioning

confidence: 99%

Nonstretching NMO correction of prestack time-migrated gathers using a matching-pursuit algorithm

Zhang

Guo

et al. 2013

GEOPHYSICS

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“…This is particularly harmful for shallow reflectors, which present relatively large offsets with respect to depth. It can also be a significant problem when searching for subtle traps (Noah 1996). Furthermore, the wavelet stretching effects have also been studied by XU & Chopra (2007) on AVO analysis and by Mann & Hoecht (2003) in the context of data‐driven imaging methods.…”

Section: Introductionmentioning

confidence: 99%

Local stretch zeroing NMO correction

Kazemi

Siahkoohi

2011

Geophysical Journal International

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S U M M A R YIn this paper we present a new method of normal move-out (NMO) correction called local stretch zeroing (LSZ) method that avoids NMO stretch. The method eliminates the theoretical curves that generate interpolated data samples responsible for NMO stretch. Pre-correction time sampling interval is preserved by reassigning and zero padding of true data samples. The optimum mute zone selection feature of the LSZ method eliminates all interfering reflection events at far offsets. The resulted stacked section from the LSZ method contains generally higher frequency components than a normal stack, and preserves most of the shallow reflectors. The LSZ method requires that zero-offset width of the time gate, i.e. zero-offset time difference between two adjacent reflections, be larger than the dominant period. The major shortcoming of the method occurs when CMP data are over-or under-NMO corrected. Both synthetic and real world examples show the efficiency of the LSZ method over the conventional NMO (CNMO) correction. The method loses its superiority when CMP data are over-or under-NMO corrected.

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