A novel method for separating intrinsic and scattering attenuation for zero-offset vertical seismic profiling data

2017 ◽  
Vol 211 (3) ◽  
pp. 1655-1668 ◽  
Author(s):  
Jun Matsushima ◽  
Mohammed Y Ali ◽  
Fateh Bouchaala
2019 ◽  
Vol 38 (11) ◽  
pp. 833-842
Author(s):  
Jacob Bayer ◽  
Bryce Jensen ◽  
Yingping Li ◽  
Tianrun Chen ◽  
Ken Matson

Between July 2018 and January 2019, Shell acquired two vertical seismic profiling (VSP) surveys in two deepwater wells in the Gulf of Mexico by using a seismic while drilling (SWD) tool. Each survey included a rig source zero-offset VSP and a boat source offset VSP. The main objective of the surveys is to delineate the salt-sediment boundary at the salt base and flank. We design and execute the complex VSP surveys with emphasis on optimization, efficiency, and integration. We develop a comprehensive analysis and processing method to integrate P-wave sediment and salt proximities with converted PS salt proximity. We use SWD-VSP surveys to demonstrate how we define the salt boundary with the integrated results. Our results show that we can delineate the salt boundary with better accuracy and with a high degree of confidence. These successful VSP surveys provide significant business and technical value.


Geophysics ◽  
2002 ◽  
Vol 67 (4) ◽  
pp. 1169-1176 ◽  
Author(s):  
Massimo Malusa ◽  
Flavio Poletto ◽  
Francesco Miranda

Surface drillstring axial pilot signals are used to predict reflections ahead of the drill bit. We show that part of the drill‐bit signal propagates downward in the formation, reflects upward by a seismic interface, and is then transmitted to the drillstring and the surface pilot sensors. These reflections are interpreted in drill‐bit pilot signals by means of a numerical model of the drillstring coupled to the formation at the bit–rock contact. The result is an additional, low‐cost, reverse VSP (RVSP) in the zero‐offset approximation. These while‐drilling results are integrated with conventional drill‐bit RVSP measurements and compared with other geophysical and well results.


Geophysics ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. D85-D91 ◽  
Author(s):  
A. Ahadi ◽  
M. A. Riahi

The aim of designing deconvolution operators is to extract the reflectivity series from seismic sections. Due to the noise, source signature inconsistency, reflection/transmission, anelastic attenuation, and multiples, the amplitude of a propagating seismic wave varies as a function of time. Because of these factors the frequency spectra of seismic signals narrow with time. Recognition of reflectors using upgoing waves is one of the notable properties of vertical seismic profiling (VSP) data. Designing a deconvolution operator for VSP data based on downgoing waves is considered to be one of the most ideal deconvolution methods intended to produce high-resolution images in routine processing of zero-offset VSP data. For such an analysis, the Gabor deconvolution operator has been designed using the downgoing wavefield and then was applied to the upgoing wavefield, and hyperbolic smoothing was used to estimate the wavelet. The final result of applying the deconvolution operator is a VSP section with superior resolution. To compare this method with customary methods of deconvolution, the Wiener deconvolution was applied to the synthetic and real data, and the results were compared with those of the Gabor deconvolution.


Geophysics ◽  
2005 ◽  
Vol 70 (2) ◽  
pp. F17-F25 ◽  
Author(s):  
Tommy Toverud ◽  
Bjørn Ursin

For seismic frequencies it is common to use an empirical equation to model attenuation. Usually the attenuation coefficient is modeled with linear frequency dependence, a model referred to as the Kolsky-Futterman model. Other models have been suggested in the geophysical literature. We compare eight of these models on a zero-offset vertical seismic profiling (VSP) data set: the Kolsky-Futterman, the power law, the Kjartansson, the Müller, the Azimi second, the Azimi third, the Cole-Cole, and the standard linear solid (SLS) models. For three separate depth zones we estimate velocities and Q-values for all eight models. A least-squares model-fitting algorithm gives almost the same normalized misfit for all models. Thus, none of the models can be preferred or rejected based on the given data set. Slightly better overall results are obtained for the Kolsky-Futterman model; for one depth zone, the SLS model gave the best result.


Geophysics ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 76-84 ◽  
Author(s):  
E. L. Majer ◽  
T. V. McEvilly ◽  
F. S. Eastwood ◽  
L. R. Myer

In a pilot vertical seismic profiling study, P-wave and cross‐polarized S-wave vibrators were used to investigate the potential utility of shear‐wave anisotropy measurements in characterizing a fractured rock mass. The caprock at The Geysers geothermal field was found to exhibit about an 11 percent velocity variation between SH-waves and SV-waves generated by rotating the S-wave vibrator orientation to two orthogonal polarizations for each survey level in the well. The effect is generally consistent with the equivalent anisotropy expected from the known fracture geometry.


2008 ◽  
Vol 168 (1-2) ◽  
pp. 103-112 ◽  
Author(s):  
Ali K. Abdel-Fattah ◽  
M. Morsy ◽  
Sh. El-Hady ◽  
K.Y. Kim ◽  
M. Sami

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