Time filter

Source Type

Kondrat'ev S.I.,Ukrainian Academy of Sciences | Prusov A.V.,Ukrainian Academy of Sciences | Yurovskii Y.G.,Ukrainian State Geological Prospecting Institute
Physical Oceanography | Year: 2010

We analyze the results of the field hydrological and hydrochemical observations of the submarine discharge of underground waters near the cape Aiya (South Coast of the Crimea) obtained with the help of the measuring equipment developed at the Marine Hydrophysical Institute of the Ukrainian National Academy of Sciences. We measure the current velocities, temperature, salinity, and the contents of silicic acid and phosphates inside a karst cavity and in the test region around the cavity. We present three estimates of the output of submarine discharge and compute the amounts of silicic acid and phosphates carried out into the sea by the submarine source. © 2010 Springer Science+Business Media, Inc.

Roganov Y.,Ukrainian State Geological Prospecting Institute | Stovas A.,Norwegian University of Science and Technology
Geophysical Prospecting | Year: 2010

The presence of triplications (caustics) can be a serious problem in seismic data processing and analysis. The traveltime curve becomes multi-valued and the geometrical spreading correction factor tends to zero due to energy focusing.We analyse the conditions for the qSV-wave triplications in a homogeneous transversely isotropic medium with vertical symmetry axis. The proposed technique can easily be extended to the case of horizontally layered vertical symmetry axis medium. We show that the triplications of the qSV-wave in a multilayered medium imply certain algebra. We illustrate this algebra on a two-layer vertical symmetry axis model. © 2009 European Association of Geoscientists & Engineers.

Marmalevskyi N.,Ukrainian State Geological Prospecting Institute | Khromova I.,Lukoil | Kostyukevych A.,Tesseral Technologies Inc
4th International Conference and Exhibition: New Discoveries through Integration of Geosciences, Saint Petersburg 2010 | Year: 2010

We consider a modification of duplex wave migration that enables seismic images of subvertical boundaries formed by waves of fixed incident angles to be obtained. This allows us to conduct AVO analysis of the subvertical boundaries for classification of faults and estimation of their properties. The role of a full-wave modeling for corrections required to obtain undistorted AVO curves is demonstrated.

Tiapkina O.,Norwegian University of Science and Technology | Landro M.,Norwegian University of Science and Technology | Tyapkin Y.,Ukrainian State Geological Prospecting Institute | Link B.,Tetrale Technologies
Geophysics | Year: 2012

The advent of single receiver point, multi-component geophones has necessitated that ground roll be removed in the processing flow rather than through acquisition design. A wide class of processing methods for ground-roll elimination is polarization filtering. A number of these methods use singular value decomposition (SVD) or some related transformations. We focus on a single-station SVD-based polarization filter that we consider to be one of the best in the industry. The method is comprised of two stages: (1) ground-roll detection and (2) ground-roll estimation and filtering. To detect the ground roll, a special attribute dependent on the singular values of a three-column matrix formed by a sliding time window is used. The ground roll is approximated and subtracted using the first two eigenimages of this matrix. To limit the possible damage to the signal, the filter operates within the record intervals where the ground roll is detected and within the ground-roll frequency bandwidth only. We improve the ground-roll detector to make it theoretically insensitive to ambient noise and more sensitive to the presence of ground roll. The advantage of the new detector is demonstrated on synthetic and field data sets. We estimate theoretically and with synthetic data the attenuation of the underlying reflections that can be caused by the polarization filter. We show that the underlying signal always loses almost all the energy on the vertical component and on the horizontal component in the ground-roll propagation plane and within the ground-roll frequency bandwidth. The only signal component, if it exists, that can retain a significant part of its energy is the horizontal component orthogonal to the above plane. When 2D 3C field operations are conducted, the signal particle motion can deviate from the ground-roll propagation plane and can therefore retain some of its energy due to a set of offline reflections. In the case of 3D 3C seismic surveys, the reflected signal always deviates from the ground-roll propagation plane on the receiver lines that do not contain the source. This is confirmed with a 2.5D 3C synthetic data set. We discuss when the ability of the filter to effectively subtract the ground roll may, or may not, allow us to ignore the inevitable harm that is done to the underlying reflected waves. © 2012 Society of Exploration Geophysicists.

Sadovenko I.,National Mining University | Rudakov D.,National Mining University | Podvigina O.,Ukrainian State Geological Prospecting Institute
New Techniques and Technologies in Mining - Proceedings of the School of Underground Mining | Year: 2010

The paper presents the results of studies concerning changes of hydrogeodynamics in the region of Central Donbass (Ukraine). The active mines are expected to be closed within the next twenty years, which requires predictive estimations for hydrogeodynamic trends in mined out strata. The studies were performed by numerical modeling of regional ground water flow. The model allowed reproducing paleohydrogeological conditions during pre-mining time, which is highly important to assess the impacts of the exploitation period. The predictive parametrical estimations were analyzed for different scenarios of mine closure. The proposed technical schemes include local draining and grouping of mine drainage; they aim eventually at self-draining of the post-mining region. © 2010 Taylor & Francis Group, London.

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