Limits on resolution enhancement for PS data mapped to PP time

Abstract

Motivated by the desire for greater resolution in PS data, and an interest in methods designed to produce this, we have explored some fundamental concepts of PS resolution in order to better understand proposed methods. Our study has produced three key results: PS-to-PP mapping using either interval or average velocity ratios yields identical results. Although mapping changes the bandwidth of the PS signal, it does not change its wavelength or resolution. Modest increases in resolution can be realized after mapping if the wavelet is known, but any method designed to increase bandwidth without such knowledge should be treated with caution.

4D simultaneous PP-PS prestack inversion in the Edvard Grieg field, Norwegian North Sea

“…Even with utmost interpretation accuracy, horizon matching registration generally leaves residual errors and may distort the PS wavelet from squeezing in time and interpolation between horizons (Ursenbach et al, 2013). This is why for the registration of the PS survey to PP time, we performed two stages of registration (1) using the Kirchoff Pre-stack Depth Migration Velocity Model and (2) horizon registration.…”

Wavelets and warping PS seismic images

“…The f and g seen in Figures 3.17a and 3.17g, respectively, have a noise-to-signal ratio of zero, and thus are the same f and g seen in Figure 3.9. images are plotted in a way that aligns events in the PP image f with those in the PS image g. Note how the PS image g is noisier than the PP image f. Ursenbach et al (2013) point out that PS images tend to have a lower frequency content than PP images because attenuation often affects S-waves more than it does P-waves. This lack of frequency content often results in poorer resolution in the PS image than in the PP image.…”

“…Because this effect is considerably worse at larger offsets and earlier times, a mute is used to zero data that is stretched beyond a set threshold. Several authors also note that the process of squeezing a PS image to PP time distorts the seismic wavelet (Bansal & Matheney, 2010;Gaiser et al, 2011Gaiser et al, , 2013Ursenbach et al, 2013). If the required amount of squeezing varies in space or time, then the warped PS wavelet also varies.…”

“…Wavelets in PP and PS traces are unlikely to be identical, in part, because attenuation often affects S-waves more than it does P-waves (Ursenbach et al, 2013). To start this iterative process, an initial wavelet is selected for either c or b.…”

Análise comparativa de aproximações não-hiperbólicas dos tempos de trânsito de dados sísmicos multicomponente utilizando tecnologia OBN

“…Thus, it was possible to identify the most appropriate approximations for each model tested, for each kind of reflection event, and for all situations studied here in a general form. (Pickett, 1963, Stewart et al, 2002, Agudelo et al, 2013, obter-se seções sísmicas de reflexão mesmo com refletividade fraca de onda P (Garrota, 1999, Stewart et al, 2002, 2003, a obtenção de uma melhor resolução dos dados sísmicos (Stewart et al, 2003;Meier et al, 2009, Ursenbach et al, 2013, melhorar o imageamento de falhas de alto ângulo (Purnell, 1992, Stewart et al, 2003, Wang et al, 2014, imagear através de nuvens de gás (Granli el al. 1995), discriminar fluidos como água e óleo em reservatórios fraturados (Qian et al, 2007), monitorar mais detalhadamente as mudanças em reservatórios de hidrocarboneto com a utilização de sísmica 4D (Spitz et al, 2000), dentre vários outros benefícios.…”