Time filter

Source Type

Verzhbitsky V.E.,TGS Nopec Geophysical Company | Khudoley A.K.,Saint Petersburg State University
4th International Conference and Exhibition: New Discoveries through Integration of Geosciences, Saint Petersburg 2010 | Year: 2010

The Laptev Sea region is one of the remote and geologically complex areas of Russian Eastern Arctic. According to the existing seismic data, a number of large offshore sedimentary basins with significant proposed hydrocarbon potential, were revealed on its shelf. No offshore wells were drilled there so far, thus all the information on the regional geology, is based on the very limited amount of marine seismic profiles and our knowledge on adjoining near-coastal areas. This study is based on the series of field works 2008-2009, carried out as a part of TGS-NOPEC Geophysical Company / St Petersburg State University joint project on Geology and Hydrocarbon systems of Northern Siberia. The field observations were done in the Laptev Sea framework, including Taimyr, Verkhoyansk and Olenek fold belts, Siberian craton, Enisey-Khatanga and Anabar-Lena depressions. Here we present some results of structural investigations of the Paleozoic-Mesozoic sedimentary complexes, exposed on Southeastern Taimyr, Bolshoy Begichev Island and Paksa Peninsula/Anabar River mouth. It is shown, that the final stage of compressional deformation in the Western Laptev Sea Region corresponds to Late Kimmerian and so is roughly synchronous with those on the rest of Eastern Arctic area, including New Siberian Islands, Chukotka and Brooks Range.


Goloshubin G.M.,University of Houston | Chabyshova E.,TGSNopec Geophysical Company
6th Saint Petersburg International Conference and Exhibition on Geosciences 2014: Investing in the Future | Year: 2014

We consider a possible explanation of the seismic low frequency anomalies using converted Fast-Slow-Fast P-waves in a thinly layered porous permeable fluid-saturated medium. Wave propagation in highly interbedded permeable gas reservoirs suggests significant and anomalous amount of mode conversions between Fast and Slow P-waves, which may be observed from surface seismic reflection data. Those converted P-waves experience high frequency dependent attenuation. In case if some converted waves propagated only a short fraction of their travel paths as Slow P-waves they will be notably delayed and attenuated relative to Fast P-wave reflections. A model of sandstone reservoir with typical parameters is used to estimate time delays of the converted Fast-Slow-Fast P-waves and their influence into total reflected P-waves energy at seismic frequencies. Copyright © 2014 by the European Association of Geoscientists & Engineers. All rights reserved.


Chabyshova E.,University of Houston | Chabyshova E.,TGSNopec Geophysical Company | Goloshubin G.,University of Houston
Geophysics | Year: 2014

P-wave amplitude anomalies below reservoir zones can be used as hydrocarbon markers. Some of those anomalies are considerably delayed relatively to the reflections from the reservoir zone. High P-wave attenuation and velocity dispersion of the observed P-waves cannot justify such delays. The hypothesis that these amplitude anomalies are caused by wave propagation through a layered permeable gaseous reservoir is evaluated. The wave propagation through highly interbedded reservoirs suggest an anomalous amount of mode conversions between fast and slow P-waves. The converted P-waves, which propagated even a short distance as slow P-waves, should be significantly delayed and attenuated comparatively, with the fast P-wave reflections. The amplitudes and arrival time variations of conventional and converted P-wave reflections at low seismic frequencies were evaluated by means of an asymptotic analysis. The calculations confirmed that the amplitude anomalies due to converted P-waves are noticeably delayed in time relatively to fast P-wave reflections. However, the amplitudes of the modeled converted P-waves were much lower than the amplitude anomalies observed from exploration cases. © 2014 Society of Exploration Geophysicists.


Suh S.Y.,TGS Nopec Geophysical Company | Yeh A.,TGS Nopec Geophysical Company | Wang B.,TGS Nopec Geophysical Company | Cai J.,TGS Nopec Geophysical Company | And 2 more authors.
Leading Edge (Tulsa, OK) | Year: 2010

Reverse time migration (RTM) is well suited for imaging steep dips in areas with high velocity contrast. In order to image steep dips at the correct positions, anisotropy has to be taken into account. In most cases, we can assume the symmetry axis is normal to the bedding, and model is tilted transverse isotropy or TTI. Figure 1 compares TTI Kirchhoff migration and TTI RTM images. We can see that the turning wave helps RTM image the steep salt flank and the steep dip truncations against the base of the salt. © 2010 Society of Exploration Geophysicists.


Masoomzadeh H.,TGS NOPEC Geophysical Co. | Hardwick A.,TGS NOPEC Geophysical Co.
74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources | Year: 2012

As an alternative to the conventional high-resolution Radon transform, we propose a time-domain approach to transform a gather of pre-stack seismic data into a gather of highly-resolved traces in the transformed domain. Using a range of various velocity functions in a standard NMO correction routine we iteratively identify the most energy-bearing functions and transfer the corresponding stackable energy consecutively. Iso-moveout functions can be used to avoid the distortions related to the NMO stretching. Application to synthetic and real data has shown improvements in resolution and performance. Higher resolution results in less ambiguous aperture compensation and therefore more successful reconstruction of stackable seismic events in the large gaps of missing data. This feature helps to improve the accuracy of modeling multiple events particularly in the near offset zone.


Krasnov A.A.,Concern CSRI Elektropribor | Sokolov A.V.,Concern CSRI Elektropribor | Usov S.V.,TGS NOPEC Geophysical Company
Gyroscopy and Navigation | Year: 2011

Special features of using a Chekan-AM gravimeter in airborne gravimetric surveys are discussed. Software and procedures for gravimetric data processing are described. The results of airborne gravimetric surveys conducted in 2007-2009 on the shelf of Greenland are given. © 2011 Pleiades Publishing, Ltd.,.


Zeng C.,TGS NOPEC Geophysical Company | Dong S.,TGS NOPEC Geophysical Company | Wang B.,TGS NOPEC Geophysical Company
Leading Edge | Year: 2014

As an inversion-based imaging algorithm, least-squares reverse time migration (LSRTM) refines seismic images toward true-reflectivity earth models. It overcomes the shortcomings of conventional migration algorithms via iterative least-squares inversion to gradually correct migration errors. LSRTM also suppresses side lobes of image wavelets to generate images with high spatial resolution. Recovered weak events and steep dips are enhanced during iterations with balanced illumination. The true-amplitude behavior of LSRTM will greatly benefit quantitative seismic interpretations. LSRTM can be a practical image-domain broadband solution to generate high-resolution images with fine layers as well as accurate complex structures. © 2014 by The Society of Exploration Geophysicists.


Zeng C.,TGS NOPEC Geophysical Company | Dong S.,TGS NOPEC Geophysical Company | Wang B.,TGS NOPEC Geophysical Company
Leading Edge | Year: 2016

Least-squares reverse time migration (LSRTM) refines the seismic image toward true reflectivity by inversion. Its iterative nature and modeling capability enable the use of synthetic data to guide the preconditioning of input data. When the velocity contains errors, dynamic warping can be used to shift the input data and force the traveltime to be consistent with the imperfect migration velocity. A crosscorrelation-based confidence level is introduced to control the quality of dynamic warping for field data. The confidence level also is used as an inverse weighting to adaptively precondition the data residual. The adaptive preconditioning automatically balances data fitting in the shallow and deep and speeds up convergence in subsalt. Both synthetic and field data experiments based in the Gulf of Mexico show that the adaptive LSRTM can improve the image quality in subsalt effectively and efficiently. Within only a few iterations, the adaptive LSRTM suppresses the salt halo artifacts and increases the signal-to-noise ratio in poorly illuminated areas. It also improves the termination of sediments against salt boundaries and enhances subsalt image coherency. Compared with conventional RTM, the adaptive LSRTM image is more favorable to geologic interpretation. © 2016 by The Society of Exploration Geophysicists.


Trademark
TGS NOPEC Geophysical Company | Date: 2013-06-19

Computer software for use on the oil and gas industry, namely computer software for seismic data processing, geophysical investigation of seismic data, and related seismic attribute and interpretation of seismic and related seismic attribute data, seismic prestack interpretation and analysis.


Trademark
TGS NOPEC Geophysical Company | Date: 2010-03-22

Prerecorded electronic media featuring geophysical data, namely seismic-data images; computer program for use in producing depth processed images from geophysical data. Computer services, namely, producing depth processed images from geophysical data; data conversion and digitization services, namely creating depth processed images from geophysical data for the oil and gas industry.

Loading TGS NOPEC Geophysical Company collaborators
Loading TGS NOPEC Geophysical Company collaborators