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2nd EAGE St Petersburg International Conference and Exhibition on Geosciences
- Conference date: 16 Oct 2006 - 19 Oct 2006
- Location: Saint Petersburg, Russia
- ISBN: 978-90-73781-64-1
- Published: 16 October 2006
101 - 120 of 209 results
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Near Surface Geophysical Investigation of the 16 Century Fortress Wall Deformation Reasons
Authors A.M. Prigara, I.A. Sanfirov, Y.I. Stepanov and G. TimofeevaComplex of the near surface geophysical researches have been made on the area of destroying 16-century historical monument. Complex included shallow seismic CDP, multi channels acoustic and radar. Using geophysical data conclusion about main negative underground water influence was received. Most dangerous parts of the fortress wall were mapped.
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Buried Karst Revealing by Near-Surface Seismic and GPR for the Pile Deepening Estimation
Authors V.P. Lisin, I.A. Sanfirov, A.I. Babkin, A.G. Jroslavtsev and L.D. PetuhovThe results of combined seismic and ground penetrating radar (GPR) profiling for the revealing of buried karst in weathered dolomite surface below morainic deposits is considered. During detailed seismic investigations reflected, refracted und surface waves are used. Combined geophysical investigations are implemented with aim of the traffic roundabout pile foundation deepening estimation during the bridge construction through Daugava river in Riga city.
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Application of 3D Seismic Diffraction Imaging for Detecting Shallow Subsurface Inhomogeneities
Authors V. Shtivelman, S. Keydar, D. Pelman and A.A. ArziRecently, a new method for detecting shallow subsurface objects utilizing the waves diffracted by these objects has been proposed. The method suggests that every subsurface point is a possible location of a point diffractor. Imaging of the diffractors is performed by stacking seismic energy in 3D space. The result of the imaging is a 3D volume in which prominent diffraction anomalies appear at spatial locations close to the target objects.
Application of the method is illustrated by a synthetic example and three case studies demonstrating imaging of various subsurface objects under various geological conditions.
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Shallow Water Multichannel Acoustic Profiling – Expectations and Realities
Authors V.G. Gaynanov, N.A. Kuzub, S.M. Klechin and R.R. LupirHigh resolution 16-channel profiling data, acquired in shallow water area, are discussed. The data quality and penetration are much better in comparison with single channel data. Though penetration dramatically drops in gas saturated sediments
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Radon as the 'determined' indicator of the natural and technological geodynamic processes
Authors V.I. Outkin, A.K. Yurkov and I.I. KosyakinRadon is considered as one of real precursors of such geodynamic phenomena as mountain impacts in deep mines and tectonic earthquakes. However physical communication between volumetric activity of radon (VAR) and the intense condition of a massif until recently was not absolutely clear. The radonic monitoring which has been carried out in deep mines, has shown, that VAR precisely fixes zones of compression and a stretching of a massif. Realization of soil radon monitoring in seismogenetic region has found out, that behavior VAR reflects compression and a stretching of a massif which are shown in conditions of a bend of a massif surface caused by geodynamic processes. On the basis of the carried out experiments the new model of preparation of geodynamic events is offered.
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Analysis and Methods of Controlling the Geodynamics Situation in the Mines of MMC Norilsk Nickel Group
Authors S.V. Tsirel, V.V. Arshavsky, B.P. Badtiev and A.N. ShabarovIn the process of deep thick ore deposit extraction the pressure of the overlying layers is exercised on preparation and extraction plots. This process includes both quasi-stationary slow movements and dynamic shifts, i. e. seismic activities. Dynamic phenomena in the vicinity of mining working may lead to their breakdown and loss of human lives.
Research on man made geodynamics process consists of a complex analysis of (1) the deposit tectonic structure, (2) mine surveying data on massif setting and (3) massif seismic activity.
Research effectuated in the mines of MMC Norilsk Nickel Group showed:
- Processes of setting and seismic activity are characterized by non-linear step-like events dependent on the activation of different faults where either quasi-stationary or dynamic forms of massif deformation are predominant.
- There exist two typical periods of seismic activity with spans of 1 or 2 years and of 2 or 3 months.
- When the space of mining is great there appear stable zones of high seismic activity linked to support pillars where mining is especially active.
- Together with the growth of seismic activity in these zones the slope of the repetition graph diminishes and powerful seismic events occur which are not subject to the repetition law.
The accepted method for diminishing the geodynamic hazard is hole off-loading at great spaces, which eases the ore stress throwing it off into the overlying and underlying strata.
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Artificial Neural Networks Approach for Well Loging Data Interpretation
Authors S. Vorobiov, V.A. Vorobiov and G.E. JakovlevGeoscientists started use artificial neural networks since early 90’s. But the most popular net configuration is preceptron error back propagation network. This paper we discus hierarchical Kohonen network and hybrid opposite direction propagation networks approach for same petrophysical problem decision, like lithology detection and porosity, permeability calculations. For porosity calculations, in case of representative core collection, we use core samples for network training, but in case of none-representative core collection we use model data for network training, the core data used only to control model reliability.
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Borehole Magnetometry in Study of the Earth Oceanic Crust Magnetoactive Layer
According to the results of three-component borehole magnetometry, conducted in boreholes of deep sea drilling by the scientific workers of the Institute of Geophysics, UB of RAS, the authore of the report determined the elements of magnetic seams bedding, calculated full, induced and remanent magnetization, which became the basis for construction of oceanic crust magnetoactive layer model.
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Petrophysical Support to Interpretation of Pulsed Neutron and Spectral Gamma Logs
Authors L.A. Ryjova, A.P. Zubarev, G.A. Kalmikov and L.A. RyjovaInterpretation of nuclear logs allows determine a material composition of rocks - mineral componential composition of solid matrix and fluid-dynamic model of a pore space. Interpretation of Pulsed Neutron and Spectral Gamma Logs is based on solution of a system of petrophysical equations where the left part includes concentrations of elements and macroscopic thermal neutron absorption cross-sections, concentrations of minerals and non-mineral components (water, oil, and gas) are unknown, and petrophysical characteristics are concentrations of elements in specific minerals and components of rocks.
Proposed is a system of extended petrophysical study of formation rocks including the following components: determination of mineral composition, content of organic matter, porosity (total and effective), residual water saturation, content of physically and chemically bounded water, density, concentrations of rock-forming, natural radioactive elements and elements –abnormal absorbers of thermal neutrons. Thus, the core analysis gives us information about the contents and elemental composition of mineral and non-mineral components.Presented are results of testing this technique for Achimov pay deposits of Zapolyarnoye field including core analysis, building of mineral-componential model, calculating petrophysical characteristics for each specific macro-component and building a resulting petrophysical model.
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Metrological Support of Geophysical Investigation of Wells
Authors A.G. Talalai, A.A. Demidov, V.G. Kazak, V.T. Perelygin and I.D. SarvartinovThe Testing Center of geophysical products accredited by Gosstandard is presented , the region of accrediting and equipping of the Testing Center is given. The works are presented on: development of technical conditions; methods of taking measurements on models and on field calibrators of neutron porosity; attestation performed by the testing center of geophysical products OOO “Uralgeostandard” of the models of neutron porosity of metrological center ZAO PGO “Tymenpromgeophysica”; coordination with VNIIM named after D.I.Mendeleyev of methodical instructions, elaborated by specialists of OOO “Neftegasgeophysica”, for carrying out of geophysical investigations with apparatuses of radioactive well-logging and processing of measurements results.
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Building a Mineral Componential Model of Formation Based on C/O and Other Through-Casing Logs
Authors V.S. Belokhin, G.A. Kalmikov and K.V. KorotkovProposed is a decomposition of measured C/O-spectra into a series of elementary spectra. As far as it is impossible measure such elementary spectra in formation calibration models, authors propose compute such spectra by the Monte-Carlo mathematical simulation. Verification of Monte-Carlo computations is performed by processing the results of C/O-log in calibration models. As a result of this approach the concentration of elements in rocks are produced. To derive oil saturation of rocks from concentrations of elements a technique for building the mineral-componential and fluidal models of formation is used. To this end such logs as spectral gamma log, neutron-neutron, and pulsed neutron-neutron logs are run. Petrophysical characteristics are computed based on the extended analysis of core samples of studied deposits. The mineral-componential and fluidal models of formation allows compute the oil-saturation index and estimate the share of movable oil, i.e., predict the oil recovery of a reservoir. The use of detailed mineral-componential and fluidal models for interpreting logs run in cased wells allows to monitor the current oil saturation of beds and identify previously bypassed interlayers. Presented are examples of applying this technique to interpreting logs acquired in the wells of Vartovsk arch, West Siberia
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Identifying Reservoirs in Bazhenian Suite Using a Combination of Spectral Gamma Ray and Other Logs
Authors O.A. Kutsenko, G.A. Kalmikov and N.K. GlebochevaFormations of Bazhenian suite are characterized by increased radioactivity caused by the decay of uranium series, increased abundance of hydrogen, reduced density of the matrix, and high electrical resistivity. The analysis of mineral composition shows that Bazhenian formations consist of siliceous material, solid organic matter and small quantity of clayey minerals. Proposed is a technique for distinguishing reservoirs of Bazhenian suite using an extended system of nuclear logs: spectral gamma, neutron log, and formation density logs. From the core analysis of Bazhenian suite of Surgut arch the following results were produced. Abnormally high concentration of uranium is related to a solid organic matter enclosed by rock matrix. Concentration of potassium and thorium mostly depends on the quantity of clayey minerals. Hydrogen content is controlled by abundances of solid organic matter, clayey minerals, and oil. Matrix density decreases with the growth of organic matter. These results have brought us to a mineral componential model of rocks of Bazhenian suite for one of the fields of the Surgut arch and find petrophysical correlations allowing to interpret well logs and identify depth intervals characterized by an increased porosity. Presented are comparisons of reservoir intervals identified from the technique proposed and well test results.
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Notisotermal Stratified Current to Oils and Water in Stem of the Horizontal Bore Hole
Authors M.F. Zakirov and R.F. SharafutdinovPresented results of mathematical modeling of the sharing the temperature and velocities of the motion fluids in stem of the horizontal bore hole at notisotermal two-phase stratified current to oils and water
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Investigation of Geoacoustic Emission in Kola Superdeep Borehole
In the Kola superdeep borehole on depth over 6000 m the phenomenon of natural seismoacoustic emission is revealed. The amplitude of seismoacoustic emission changes in time and on depth. Acoustic emission is the response of the geological environment to deformation processes.
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Rayleigh-Type Waves for the Isotropic Elastic Reduced Cosserat Half-Space. Application in Rocks and Soils
Authors E.F. Grekova and M.A. KuleshWe continue in this paper the work on the modelisation of rocks and soils in terms of the elastic reduced Cosserat continuum. The basic idea of the model is to take into account the mictrostructure of rocks and soils which influences the wave propagation, for some frequency range trapping the energy of the propagating wave by their proper rotational motion. We consider the Rayleigh wave for the isotropic case, using analytical and numerical methods. Instead of a straight line in the classical medium, we obtain two dispersion curves. The polarization differs both from the case of classical medium and the case of Cosserat continuum with couple stresses. We observe for some frequency range a strong frequency dependence. There is a forbidden band of frequencies, lying below the analogous forbidden band for an unbounded medium. It indicates the possibility of localization phenomena. For the upper branch of dispersion relation, there is also a forbidden domain of wave numbers: long waves may propagate only with one frequency. Far from the domain of frequencies where the microstructure influences the wave propagation, the medium behaves analogously to the classical one.
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Retrieving Anisotropy Parameter e with Diving P-Waves Travel Tomography
Authors K.V. Bykov, Y.V. Kiselev, V.N. Troyan and B.M. KashtanA correct anisotropic velocity model is critical for seismic imaging. We investigate here the possible advantages of inverting simultaneously for reflected and diving waves using P-waves recorded at the surface. Simple tests in 1-D and 2-D VTI (Vertical Transversely Isotropic) models with spatially varying Vp and e show that reflected energy alone only provides partial information on the sub-surface properties after travel time tomography. However, both the velocity profile Vp, the depth interfaces and e can be well inverted by combining the two types of waves in the 1-D and 2-D examples investigated here.
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Full Waveform Inversion of VSP Data for Prediction of Impedances bellow Borehole Bottom
More LessThis work is devoted to the studying of possibility of implementation of full waveform inversion for arrangement the elastic impedances bellow the borehole bottom. The VSP surveying system with one offset source is used. We deal with 2D isotropic elastic media. In this paper we present the result of singular value decomposition (SVD) analysis. Also some numerical results of inversion are shown.
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Estimation of Accuracy of the Medium Parameters Restoration by Diffraction Tomography and Iterative Procedure
Authors V.N. Troyan and Y.V. KiselevThe results of numerical simulation on restoration of local inhomogeneities with the sizes exceeding the wavelength of the sounding signal and with the contrast of shear modulus smaller than 1.0. The restoration of inhomogeneities using iterative approach together with the diffraction tomography method based on the first-order Born approximation is studied. At the each step of the iterative procedure the direct problem (1-D or 2-D SH problem) is solved by the finite difference method to calculate the difference field between the “experimental” data and the model data. The difference field is used to restore the shear modulus of desired inhomogeneity by the algebraic procedure with an appropriate regularization. The results of such restoration we compare with restoration using back projection approximation.
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Velocity Model Refinement in Vicinity of a Borehole by Dynamically Based Traveltime Inversion (Case of Offset VSP)
By D. NeklyudovWe propose some development of wave equation traveltime inversion algorithm that provides the possibility to process both transmitted and reflected waves and to use Newton-like technique for macro-velocity refinement. At each iteration of nonlinear kinematical inversion we solve a linearized inverse problem using LSQR algorithm to obtain a small perturbation of a current macrovelocity model which minimizes traveltime residuals. Numerical experiments with a synthetic and real data have shown that our approach can be successfully applied for improvement of the near borehole velocity in the case of offset VSP survey.
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Studying the processes of the formation of seismic wave fields in transit zones during the winter period
Authors V.G. Khaidukov, S.V. Goldin, O.M. Gorskiy and V.A. CheverdaВ работе исследуется причина возникновения интенсивного случайно-коррелированного шума, возникающего при наблюдениях на льду замерзших водоемов. По результатам численного моделирования установлено, что наиболее вероятной причиной его могут служить неровности границ ледяного покрова.
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