Geologia
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ISSN 0138-0974
e-ISSN: 2353-0782
Issue Date
2010
Volume
T. 36
Number
Nr 2
Description
Journal Volume
Geologia
T. 36 (2010)
Projects
Pages
Articles
Wyniki badań nad lokalnymi zmianami pola magnetycznego Ziemi na lubelskim skłonie wschodnioeuropejskiego kratonu (profil Parczew – Chełm)
(Wydawnictwa AGH, 2010) Bojdys, Grzegorz; Grabowska, Teresa; Wójcik, Aleksander; Medoń, Zdzisława
The local relative changes of the total intensity geomagnetic field in time are presented against the background of the geological structure of Lublin-Podlasie slope (LPSK) of the East European Craton. The research concerned measurement results of the total intensity (T) of the geomagnetic field, taken in the last 12 years (1997-2008) at 20 sites located along the Parczew - Chełm profile. Relative temporal changes of the geomagnetic field were determined on the basis of values of geomagnetic field calculated with reference to geomagnetic field measured at the base. These changes are presented as graphs, and in the form of space-time 2D and 3D representations, showing their relationship with the magnetic anomaly map. The cause of local relative changes was attempted to be explained by 2D magnetic modeling assuming that the changes of the induced magnetization of the basement crystalline rocks are result of the geomagnetic secular variations.
Wykorzystanie sejsmostratygrafii do rozpoznania rozkładu mioceńskich facji zbiornikowych w północno-wschodniej części zapadliska przedkarpackiego
(Wydawnictwa AGH, 2010) Pietsch, Kaja; Porębski, Szczepan J.; Marzec, Paweł
Sedimentological and seismostratigraphic interpretation of a dip cross-section located in the northwestern part of the Wielkie Oczy Graben, across the Markowice - Lubliniec elevation and farther to the NE resulted in the identification of the base-Sarmatian angular unconformity (UNO) and allowed to subdivide the Machów Formation into seven genetic sequences composed mainly of deltaic deposits. The unconformity reflects extension episode superimposed on regional south-westward rotation of the basin floor and is overstepped and upplapped towards the NE by deltaic bodies fed from an southerly (orogenic) source. The upplaping pinchouts may form combined, structural-stratigraphic traps for methane generated in delta front-prodelta heteroliths. Unconformity UNO is farther to the SE overlain locally by gas-bearing massive sandstones of intrabasinal or northerly provenience, and similar sandstones may be expected to occur in the study area below the belt of upplapping pinch-outs.
Visualization of magnetotelluric data with apparent velocity method
(Wydawnictwa AGH, 2010) Miecznik, Juliusz; Klityński, Wojciech
Magnetotelluric (MT) field data are usually presented as plots of amplitude and phase MT sounding data vs frequency. Visualization of resistivity changes of geoelectric complexes with the use of apparent resistivity and phase curves give qualitative results only. Quantitative interpretation of MT sounding curves is needed to get geoelectric parameters. For a 1D horizontally layered earth, amplitude curves (apparent resistivity curves) and phase curves can be transformed into apparent velocity curves versus depth of EM field penetration into the conducting earth. Apparent velocity curves can be approximated by straight-line segments corresponding to homogeneous geoelectric layer complexes. Each segment of the apparent velocity curve (with a given angle of inclination) is related with the resistivity and thickness of individual geoelectric complexes. For heterogeneous earth (2D or 3D) vertical component of the magnetic field is directly connected with boundary of geo-electric complexes. It can be used to express components of vectors of apparent velocity. For a 1D horizontally layered earth, a vector of apparent velocity has only the vertical component. For heterogeneous earth horizontal components of apparent velocity also are inducted. The angle of inclination of the total vector of velocity and its value depend on the geometry of studied structure.
The analysis of the effectiveness of the seismic noise attenuation by means of Karhunen-Loeve (K-L) transform
(Wydawnictwa AGH, 2010) Kasina, Zbigniew
In the paper the analysis of the effectiveness of multiples and random noise attenuation using Karhunen-Loeve (K-L) transform is presented. The K-L transform is realized with application the process Eigenimage Filter in seismic data processing system ProMAX. The basic part of the paper is directed to the analysis of multiples attenuation by means of the K-L transform applied to field data. In the analysis the common shot point gathers (seismic records) were used as well as the traces of the CDP gathers. In the case of CDP gathers the main attention was paid on the multiple attenuation in the averaged CDP gathers (supergathers) prepared for the interactive velocity analysis. The influence of the K-L filter parameters was defined on the effectiveness of multiples removing from the velocity analysis wave images. Finally the effectiveness of the K-L filter was estimated in improving the coherent to random signals ratio on the seismic records.
Ocena typu zailenia w skałach piaskowcowo-ilastych na podstawie danych geofizyki otworowej - metoda wykresów krzyżowych
(Wydawnictwa AGH, 2010) Bała, Maria
The analysis of effects of shale distribution and clay volume in reservoir formations on well logging curves is presented in this paper. A conception given originally by Thomas & Stieber (1975) was applied into modelling the response of well logging tools for an assumed shaly-sand model. Results of calculations were compared with logs registered in the J4 well which drilled the autochthonous Miocene deposits. Different crossplots obtained based on Gamma Ray and Neutron and Density or Acoustic logs prove that there is a possibility to determine porosity, shale distribution and sand volume (net to gross) in the reservoir horizons.