Wyniki wyszukiwania - Biblioteka Nauki

1

Detection of the Long Period Long Duration (LPLD) Events in Time- and Frequency-Domain

100%

Kwietniak A.

Acta Geophysica

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2015

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tom Vol. 63, no. 1

201--213

EN

Long Period Long Duration (LPLD) signals are unusual seismic events that can be observed during hydraulic fracturing. These events are very similar in appearance to tectonic tremors sequences, which were first observed in subduction zones. Their nature is not well known. LPLD might be related to the productivity of the reservoir. Different methods of the LPLD events’ detection recorded during hydraulic fracturing are presented. The author applied two methods for LPLD detection – Butterworth filtering and Continuous Wavelet Transform (CWT). Additionally, a new approach to LPLD events detection – instantaneous seismic attributes – was used, common in a classical seismic interpretation but not in microseismic monitoring.

2

Verification of bright spots in the presence of thin beds by AVO and spectral analysis in Miocene sediments of Carpathian Foredeep

51%

Cichostępski K. , Kwietniak A. , Dec J.

Acta Geophysica

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2019

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tom Vol. 67, no. 6

1731--1745

EN

Twin structural traps that lie within the Miocene strata of the Carpathian Foredeep that are localized above Cierpisz and Mrowla-Bratkowice highs exhibit identical bright-spot seismic anomalies, but only those associated with the Cierpisz high are profitable gas reservoirs. Bright spots can be a result of weak gas or water saturation, but also seismic interference known as tuning effect. For these reasons, it is crucial to differentiate between seismic anomalies. In this article, we present the possibilities of verification of seismic anomalies that occur within the siliciclastic Miocene sediments of the Carpathian Foredeep with the application of AVO analysis and spectral decomposition. AVO methodology enabled to limit the number of anomalies that are present in the post-stack seismic data. These anomalies, however, may also be a result of tuning which is common for the heterolithic sequences in the Miocene sediments of the Carpathian Foredeep. For classification of anomalies in the view of the above, spectral decomposition based on the Basis Pursuit algorithm was applied. Spectral decomposition enabled to divide AVO anomalies in those that are the result of gas saturation and the tuning effect. Gas-saturated zones are characterized by higher spectral amplitudes of the lower frequency range, whereas tuning effect yields higher spectral amplitudes for the higher frequency content. This relation is visible for the data set and enables qualitative differentiation for the set of seismic anomalies.

3

Relative amplitude preservation in high‑resolution shallow reflection seismic: a case study from Fore‑Sudetic Monocline, Poland

51%

Cichostępski K. , Dec J. , Kwietniak A.

Acta Geophysica

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2019

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tom Vol. 67, no. 1

77--94

EN

The acquisition parameters and methodology of seismic data processing for high-resolution seismic imaging viewed through relative amplitude preservation are presented. An example of the obtaining of high-quality, shallow seismic data with a variable end-on spread is shown. The source used for the project is an accelerated weight drop. The study area lies within the mine waste disposal area, near Rudna village (Fore-Sudetic Monocline, WS Poland), and results are given for a 2D experimental profile. The aim of the project was to design optimal acquisition and processing parameters for the detailed recognition of Tertiary deposits. The proposed acquisition parameters are a compromise between time, cost and results. High-resolution seismic imaging enables the determining of layers within the range of thicknesses between 5 and 15 m, while the maximal depth of imaging reaches 400 m.

4

Spectral Decomposition Using the CEEMD Method: a Case Study from the Carpathian Foredeep

51%

Kwietniak A. , Cichostępski K. , Kasperska M.

Acta Geophysica

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2016

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tom Vol. 64, no. 5

1525--1541

EN

The purpose of this work is to select the optimal spectral decomposition (SD) method for channel detection in the Miocene strata of the Carpathian Fordeep, SE Poland. For analysis, two spectral decomposition algorithms were tested on 3D seismic data: the first, based on Fast Fourier Transform (FFT), and second, on Complete Ensemble Empirical Mode Decomposition (CEEMD). Additionally the results of instantaneous frequency (IF) were compared with the results of peak frequency (PF) computed after the CEEMD. Both algorithms of SD enabled us to interpret channels, but the results are marginally different, i.e. the FFT shows more coarse, linear structures, that are desirable for channel interpretation, whereas the CEEMD does not highlight these structures as clearly and shows more, what the authors believe to be, noise.