Факторы и динамика изменчивости фильтрационных свойств пород острова Змеиный
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Дата
2017
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Одесский национальный университет имени И.И. Мечникова
Анотація
В статье приведены результаты исследований динамики поведения водопроводимости напорного водоносного горизонта в девонских отложениях острова Змеиный. На основе кроссспектрального анализа временных рядов установлена корреляция между изменениями водопроводимости и вариациями уровня моря, среднего расстояния Земля-Луна, а также скорости осевого вращения Земли. Установлено, что в пределах низких частот водопроводимость связана с указанными факторами по линейному закону, в высокочастотной области вариации корреляций имеют неустойчивый характер.
Problem Statement and Purpose. Transmissivity (T) is one of the most important parameters in determining aquifer productivity and generally estimated from pumping tests. This study (for the period 01.2005-04.2008) focuses on the transmissivity behavior dynamic for pressure fractured-rock aquifer in the Devonian deposits of the Zmeinyi island. It presents a temporal variations in transmissivity under the influence of sea level, distance Earth-Moon and axial rotation of the Earth. Data & Methods. In the paper have studied the data from the experimental pumping test of the exploited well No 2, situated in the northwestern part of Zmeinyi island, having a depth of 50 m. Time-recovery plots (270 plots) were analyzed by using. Theis Jacob method to obtain transmissivity. The geologic setting in the study area is generally composed of the Paleozoic deposits, including the Silurian and Devonian, as well as the Cenozoic formations. The lithology of the aquifer varies widely and includes conglobreccia, sandstone, conglomerate, mudstone and siltstone. By results of well logging tests for water-bearing rocks the following thickness intervals were established: 38.0-54.6 m; 57.6-74.0 m; 80.8-109.4 m. Within the upper interval represented by conglomerates, there are two aquifer subhorizons, separated by weakly fractured rocks, that is by relatively waterproof layer. A comparison of water-bearing rocks depth intervals and static water levels shows that ground water in the upper subhorizon is under pressure. Results. On the basis of a cross-spectral analysis of time series (using frequency transfer functions, coherence spectra and phase difference) correlations were revealed between variations of transmissivity and the following factors: sea level, mean Earth-Moon distance, Earth rotation speed. Variations in the correlation between transmissivity and factors influencing it allow assessing stress-strain state of water-bearing rocks. The results obtained from cross-spectral analysis showed that in the low frequency range, transmissivity is related to these factors linearly. In the range of periods from 5.5 to 11 days the Earth-Moon distance increases, the transmissivity value decreases and vice versa, with decreasing Earth-Moon distance (T) increases. For the same periods for accelerated motion of the Earth (T) increases, and vice versa, a decrease in Earth’s rotation speed is accompanied by a decrease of (T). For the sea level, for periods from 5.5 to 11 days, transmissivity is in the antiphase with sea level variations. The increase in sea water level corresponds to a decrease of (T) and decrease of sea water level corresponds to increase of (T).
У статті наведено результати досліджень динаміки поведінки водопровідності напірного водоносного горизонту в девонських відкладах острова Зміїний. На основі крос-спектрального аналізу часових рядів встановлена кореляція між змінами водопровідності і варіаціями рівня моря, середньої відстані ЗемляМісяць, а також швидкості осьового обертання Землі. Встановлено, що в межах низьких частот водопровідність пов’язана із зазначеними факторами за лінійним законом, у високочастотної зоні варіації кореляцій мають нестійкий характер
Problem Statement and Purpose. Transmissivity (T) is one of the most important parameters in determining aquifer productivity and generally estimated from pumping tests. This study (for the period 01.2005-04.2008) focuses on the transmissivity behavior dynamic for pressure fractured-rock aquifer in the Devonian deposits of the Zmeinyi island. It presents a temporal variations in transmissivity under the influence of sea level, distance Earth-Moon and axial rotation of the Earth. Data & Methods. In the paper have studied the data from the experimental pumping test of the exploited well No 2, situated in the northwestern part of Zmeinyi island, having a depth of 50 m. Time-recovery plots (270 plots) were analyzed by using. Theis Jacob method to obtain transmissivity. The geologic setting in the study area is generally composed of the Paleozoic deposits, including the Silurian and Devonian, as well as the Cenozoic formations. The lithology of the aquifer varies widely and includes conglobreccia, sandstone, conglomerate, mudstone and siltstone. By results of well logging tests for water-bearing rocks the following thickness intervals were established: 38.0-54.6 m; 57.6-74.0 m; 80.8-109.4 m. Within the upper interval represented by conglomerates, there are two aquifer subhorizons, separated by weakly fractured rocks, that is by relatively waterproof layer. A comparison of water-bearing rocks depth intervals and static water levels shows that ground water in the upper subhorizon is under pressure. Results. On the basis of a cross-spectral analysis of time series (using frequency transfer functions, coherence spectra and phase difference) correlations were revealed between variations of transmissivity and the following factors: sea level, mean Earth-Moon distance, Earth rotation speed. Variations in the correlation between transmissivity and factors influencing it allow assessing stress-strain state of water-bearing rocks. The results obtained from cross-spectral analysis showed that in the low frequency range, transmissivity is related to these factors linearly. In the range of periods from 5.5 to 11 days the Earth-Moon distance increases, the transmissivity value decreases and vice versa, with decreasing Earth-Moon distance (T) increases. For the same periods for accelerated motion of the Earth (T) increases, and vice versa, a decrease in Earth’s rotation speed is accompanied by a decrease of (T). For the sea level, for periods from 5.5 to 11 days, transmissivity is in the antiphase with sea level variations. The increase in sea water level corresponds to a decrease of (T) and decrease of sea water level corresponds to increase of (T).
У статті наведено результати досліджень динаміки поведінки водопровідності напірного водоносного горизонту в девонських відкладах острова Зміїний. На основі крос-спектрального аналізу часових рядів встановлена кореляція між змінами водопровідності і варіаціями рівня моря, середньої відстані ЗемляМісяць, а також швидкості осьового обертання Землі. Встановлено, що в межах низьких частот водопровідність пов’язана із зазначеними факторами за лінійним законом, у високочастотної зоні варіації кореляцій мають нестійкий характер
Опис
Ключові слова
водоносный горизонт, aquifer, водопроводимость, кроссспектральный анализ, остров Змеиный, transmissivity, cross-spectral analysis, Zmeinyi island, водоносний горизонт, водопровідність, крос-спектральний аналіз, острів Зміїний
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Вісник ОНУ.