Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

2 Acta Geophysica

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

The influence of the frequency‑dependent spherical‑wave effect on the near‑surface attenuation estimation

100%

Ji Y. , Wang S. , Yuan S. , Yan B.

tom Vol. 67, no. 2

577--587

The knowledge of Q is desirable for improving seismic resolution, facilitating amplitude analysis and seismic interpretation. The most commonly used methods for Q estimation are the frequency-spectrum-based methods. Generally, these methods are based on the plane wave theory assuming that the transmission/reflection loss is frequency independent. This assumption is reasonable in the far-field situation and makes the transmission/reflection coefficient irrelevant with the Q estimation result. However, in the near-surface context, this assumption is invalid because the seismic wave propagates in the form of spherical wave in the real seismic surveys and the spherical-wave transmission/reflection coefficient is frequency dependent. As a result, deviation will exist. In this paper, the influence of the spherical-wave effect on the Q estimation in the near-surface context was proved in both synthetic data and field data for the first time, and it was found that the deviation due to the sphericalwave effect is of order comparable to the intrinsic attenuation. The compensation method based on the forward modeling is then proposed to correct this deviation, and the effectiveness of the proposed method is proved by the reasonable estimated results of both synthetic data and field data example. These results raise caution for the interpretation of the extracted Q in the near-surface context if they do not account for the spherical-wave effect and point to the necessity of incorporating a frequency-dependent term in the frequency-spectrum-based method when applied to the Q estimation in the near surface.

Multichannel sparse spike deconvolution based on dynamic time warping

88%

Zhao X. , Wang S. , Yuan S. , Cheng L. , Cai Y.

tom Vol. 69, no. 3

783--793

Seismic sparse spike deconvolution is commonly used to invert for subsurface refectivity series and is usually implemented as an inversion scheme. Conventional sparse spike deconvolution method does not utilize the relationships among adjacent traces resulting in instability and poor lateral continuity of the inverted result. We propose a multichannel sparse spike deconvolution method with a sparsity-promoting constraint and an extra lateral constraint exploiting the spatial relationships among adjacent seismic traces. Firstly, the dynamic time warping (DTW) is performed between any two adjoining seismic traces to obtain the warping path (a series of estimated time shifts of one seismic trace relative to the other). Based on the assumption that if the inverted refectivity series is convolved with the same wavelet used for inversion, the newly constructed adjoining seismic traces shall also be conformable to the relationships exploited among the original seismic traces by DTW. A diference operator is constructed with the estimated time shifts to guarantee the diference operation is performed between corresponding time samples on adjoining seismic traces and the inversion is regularized with this diference operator as the lateral constraint. Synthetic and real data case studies confrm that inverted result obtained by the proposed method is superior to those obtained by single-channel sparse spike deconvolution method and another multichannel deconvolution method based on horizontal frst-order derivative constraint in both signal-to-noise ratio and lateral continuity.