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- ItemAmbient noise analysis for characterizing sub-surface dynamic parameters(London [u.a.] : Institute of Physics, 2020) Setiawan, B.; Saidi, T.; Yuliannur, A.; Polom, U.; Ramadhansyah, P.J.; Ali, M.I.Ambient noise analysis of horizontal to vertical spectral ratio (HVSR) method has been used widely to provide reliable estimates of the site fundamental frequency and to constrain the inversion of near-surface shear wave velocity. The present paper focuses on the site measurement using the aforementioned analysis by means of the HVSR method for characterizing sub-surface dynamic parameters in the City of Banda Aceh, Indonesia. A Guralp CMG-6TD broadband seismometer was used in this study to cover a wide frequency range from 0.033 Hz to 50 Hz in standard operation. The instrument was deployed at two different sites (i.e. Location#1 of Blang Padang and Location#2 of Stadion Dirmutala) in the City of Banda Aceh for at least 2 hours for ambient noise recording. This continuous of 2 hours' microtremor time series was separated into 30 minutes record from which the site fundamental frequency and shear wave velocity of the measured site were deduced. The later sub-surface dynamic parameter was validated using another technique of reflection seismic. This investigation suggests the fundamental frequency of 0.45 Hz at Location#1 and of 0.65 Hz at Location#2. The estimated shear wave velocity of the top 30 m, Vs,30 of this investigation is 165 m/s at Location#1 and 156 m/s at Location#2. Both the site fundamental frequency and shear wave velocity are important for infrastructure design in the high seismic region of Banda Aceh, Indonesia.
- ItemChronostratigraphy of silt-dominated Pleistocene periglacial slope deposits on Mt. Ślęża (SW, Poland): Palaeoenvironmental and pedogenic significance(New York, NY [u.a.] : Elsevier, 2020) Waroszewski, Jaroslaw; Sprafke, Tobias; Kabala, Cezary; Musztyfaga, Elżbieta; Kot, Aleksandra; Tsukamoto, Sumiko; Frechen, ManfredSlope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified. The concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture; yet there is a remaining debate on processes and the timing of their formation. A previous study done by us at Mt. Ślęża, SW Poland, concluded that slope deposits with variable aeolian silt admixture, or its lack, have a significant influence on the pathway of soil formation. The present work builds upon this finding, by adding further granulometric and micromorphological data from three representative profiles along a toposequence, in order to refine our understanding of local slope deposits and soil formation. Additionally, seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions. The oldest aeolian deposits are of Middle Pleistocene age (>280 ± 19 ka) with interlayered palaeosol (marine isotope stage [MIS] 9 or older). Late Pleistocene slope deposits encompass the maximum loess thickness and are dated to MIS 2. Luminescence ages from the upper layers indicate shallow reworking, which we tentatively correlate to the Younger Dryas (YD). Two profiles with thick loess mantles have strong clay illuviation features, presumably formed during the Holocene. However, weak clay illuviation in the third profile with a thin loess mantle (having an age of YD) over granite regolith seems to have occurred before the Holocene, as only fragmented clay coatings (probably MIS 2 pedogenesis) could be found. © 2020 The Authors
- ItemCopper-iron bimetal ion-exchanged sapo-34 for NH3-scr of NOx(Basel : MDPI, 2020) Doan, Tuan; Dam, Phong; Nguyen, Khang; Vuong, Thanh Huyen; Le, Minh Thang; Pham, Thanh HuyenSAPO-34 was prepared with a mixture of three templates containing triethylamine, tetraethylammonium hydroxide, and morpholine, which leads to unique properties for support and production cost reduction. Meanwhile, Cu/SAPO-34, Fe/SAPO-34, and Cu-Fe/SAPO-34 were prepared through the ion-exchanged method in aqueous solution and used for selective catalytic reduction (SCR) of NOx with NH3. The physical structure and original crystal of SAPO-34 are maintained in the catalysts. Cu-Fe/SAPO-34 catalysts exhibit high NOx conversion in a broad temperature window, even in the presence of H2O. The physicochemical properties of synthesized samples were further characterized by various methods, including XRD, FE-SEM, EDS, N2 adsorption-desorption isotherms, UV-Vis-DRS spectroscopy, NH3-TPD, H2-TPR, and EPR. The best catalyst, 3Cu-1Fe/SAPO-34 exhibited high NOx conversion (> 90%) in a wide temperature window of 250–600 °C, even in the presence of H2O. In comparison with mono-metallic samples, the 3Cu-1Fe/SAPO-34 catalyst had more isolated Cu2+ ions and additional oligomeric Fe3+ active sites, which mainly contributed to the higher capacity of NH3 and NOx adsorption by the enhancement of the number of acid sites as well as its greater reducibility. Therefore, this synergistic effect between iron and copper in the 3Cu-1Fe/SAPO-34 catalyst prompted higher catalytic performance in more extensive temperature as well as hydrothermal stability after iron incorporation. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemTwo-Phase Fluid Flow Experiments Monitored by NMR(Les Ulis : EDP Sciences, 2020) Hiller, Thomas; Hoder, Gabriel; Amann-Hildenbrand, Alexandra; Klitzsch, Norbert; Schleifer, NorbertWe present a newly developed high-pressure nuclear magnetic resonance (NMR) flow cell, which allows for the simultaneous determination of water saturation, effective gas permeability and NMR relaxation time distribution in two-phase fluid flow experiments. We introduce both the experimental setup and the experimental procedure on a tight Rotliegend sandstone sample. The initially fully water saturated sample is systematically drained by a stepwise increase of gas (Nitrogen) inlet pressure and the drainage process is continuously monitored by low field NMR relaxation measurements. After correction of the data for temperature fluctuations, the monitored changes in water saturation proved very accurate. The experimental procedure provides quantitative information about the total water saturation as well as about its distribution within the pore space at defined differential pressure conditions. Furthermore, the relationship between water saturation and relative (or effective) apparent permeability is directly determined. © The Authors, published by EDP Sciences, 2020.
- ItemA post-IR IRSL chronology and dust mass accumulation rates of the Nosak loess-palaeosol sequence in northeastern Serbia(Oxford [u.a.] : Wiley-Blackwell, 2020) Perić, Zoran M.; Marković, Slobodan B.; Sipos, György; Gavrilov, Milivoj B.; Thiel, Christine; Zeeden, Christian; Murray, Andrew S.In the Middle Danube Basin, Quaternary deposits are widely distributed in the Vojvodina region where they cover about 95% of the area. Major research during the last two decades has been focused on loess deposits in the Vojvodina region. During this period, loess in the Vojvodina region has become one of the most important Pleistocene European continental climatic and environmental records. Here we present the dating results of 15 samples taken from the Nosak loess-palaeosol sequence in northeastern Serbia in order to establish a chronology over the last three glacial–interglacial cycles. We use the pIRIR290 signal of the 4–11 μm polymineral grains. The calculated ages are within the error limits partially consistent with the proposed multi-millennial chronostratigraphy for Serbian loess. The average mass accumulation rate for the last three glacial–interglacial cycles is 265 g m−2 a−1, which is in agreement with the values of most sites in the Carpathian Basin. Our results indicate a highly variable deposition rate of loess, especially during the MIS 3 and MIS 6 stages, which is contrary to most studies conducted in Serbia where linear sedimentation rates were assumed. © 2020 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium
- ItemA new method for correcting temperature log profiles in low-enthalpy plays(Berlin ; Heidelberg [u.a.] : Springer Open, 2020) Schumacher, Sandra; Moeck, IngaTemperature logs recorded shortly after drilling operations can be the only temperature information from deep wells. However, these measurements are still influenced by the thermal disturbance caused by drilling and therefore do not represent true rock temperatures. The magnitude of the thermal disturbance is dependent on many factors such as drilling time, logging procedure or mud temperature. However, often old well reports lack this crucial information so that conventional corrections on temperature logs cannot be performed. This impedes the re-evaluation of well data for new exploration purposes, e.g. for geothermal resources. This study presents a new method to correct log temperatures in low-enthalpy play types which only requires a knowledge of the final depth of the well as an input parameter. The method was developed and verified using existing well data from an intracratonic sedimentary basin, the eastern part of the North German Basin. It can be transferred to other basins with little or no adjustment. © 2020, The Author(s).
- ItemPredictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well(Berlin ; Heidelberg [u.a.] : Springer Open, 2020) Drews, Michael C.; Hofstetter, Peter; Zosseder, Kai; Shipilin, Vladimir; Stollhofen, HaraldThe North Alpine Foreland Basin in SE Germany is Germany’s most active deep geothermal province. However, in its southern and eastern part the basin is considerably overpressured, which is a significant challenge for drilling deep geothermal wells. In this study, we combine drilling data and velocity-based pore pressure analyses with 3D basin modeling to assess the predictability and controlling factors of overpressure in the sub-regional context (area of 80 km × 50 km) around the Geretsried GEN-1 well, a deep geothermal exploration well in the southern part of the North Alpine Foreland Basin in SE Germany. Drilling data and velocity-based pore pressure analyses indicate overpressure maxima in the Lower Oligocene (Rupelian and Schoeneck Formation) and up to mild overpressure in the Upper Oligocene (Chattian) and Upper Cretaceous, except for the hydrostatically pressured northwestern part of the study area. 3D basin modeling calibrated to four hydrocarbon wells surrounding the Geretsried GEN-1 well demonstrates the dominating role of disequilibrium compaction and low permeability units related to overpressure generation in the North Alpine Foreland Basin. However, secondary overpressure generation mechanisms are likely contributing. Also, the impact of Upper Cretaceous shales, which are eroded in the northwestern part of the study area, on overpressure maintenance is investigated. The calibrated basin model is tested against the drilling history and velocity (VSP) data-based pore pressure estimate of the Geretsried GEN-1 well and reveals that pore pressure prediction is generally possible using 3D basin modeling in the North Alpine Foreland Basin, but should be improved with more detailed analysis of lateral drainage systems and facies variations in the future. The results of the study are of relevance to future well planning and drilling as well as to geomechanical modeling of subsurface stresses and deep geothermal production in the North Alpine Foreland Basin. © 2020, The Author(s).
- ItemProbability of success studies for geothermal projects in clastic reservoirs: From subsurface data to geological risk analysis(Amsterdam [u.a.] : Elsevier Science, 2020) Schumacher, Sandra; Pierau, Roberto; Wirth, WolfgangIn the realisation of a geothermal project, an important step is the quantification of the geological risk of a well not achieving the economically necessary cut-off values with respect to temperature and flowrate/drawdown. In this paper, we present a new method for calculating this risk via a probability of success study by using all available types of hydraulic data, including porosity values derived from core samples or borehole logs. This method has been developed for geothermal projects in fluvial sandstones of the North German Basin but can be applied to any clastic, not fracture-dominated reservoir worldwide. © 2019 The Authors
- ItemS-wave seismic imaging of near-surface sediments using tailored processing strategies(Amsterdam [u.a.] : Elsevier Science, 2020) Burschil, Thomas; Buness, HermannReflection seismic imaging using horizontally-polarized S-waves (SH) can increase resolution and it could be cost-efficient compared to the common use of P-waves. However, since S-wave application often delivers varying data quality, appropriate processing schemes are required for particular imaging and interpretation purposes. In this paper, we present four tailored processing strategies that are applied to SH-wave data acquired in an overdeepened Quaternary basin in the Alpine foreland, the Tannwald Basin. The applied processing schemes consist of (1) processing using a short automatic gain control window that enhances structural details and highlights small-scale structures, (2) offset restriction indicating that relative small offsets are sufficient for adequate imaging, which offers reduced field operation costs, (3) coherency-enhancement that reveals large-scale structures for interpretation, and (4) adapted amplitude scaling that enables structural comparison of P-wave and S-wave seismic sections. With respect to P-wave data measured on the same profile, we demonstrate the benefits of the S-wave seismic reflection method. P-waves offer robust imaging results, but S-waves double the resolution, better depict shallow reflections, and may image reflectors in areas where the P-wave struggles. At least for the Tannwald Basin, S-wave imaging is also more cost-efficient than P-wave imaging. © 2020 The Authors
- ItemNon-remote reference noise cancellation - using reference data in the presence of surface-NMR signals(Amsterdam [u.a.] : Elsevier Science, 2020) Müller-Petke, MikeSurface-NMR measurements commonly suffer from low signal-to-noise ratios. In recent years, with the introduction of multi-channel surface-NMR instruments, the technique of remote-reference noise cancellation (RNC) was developed and significantly improved the applicability of surface-NMR. The current formulation of RNC requires a reference loop to be placed a remote distance from the transmitter loop such that no NMR signal is recorded. Reference loops placed at non-remote distances have been envisaged to provide both improved noise cancellation performance and field efficiency; however, the concept has not been previously applied because the theoretical framework was missing. In this paper, the theoretical framework is presented. It is demonstrated that reference loops placed at non-remote distances provide superior noise cancellation performance. Considerations for placing the reference loop relative to the transmitter loop are provided, and the theoretical framework is evaluated based on a semi-synthetic example using real field noise and synthetic surface-NMR data. © 2020
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