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Winsemann J.,Leibniz University of Hanover | Pollok L.,Leibniz University of Hanover | Polom U.,LIAG | Brandes C.,Leibniz University of Hanover
74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources | Year: 2012

In this paper we will document the stratigraphic evolution, internal facies architecture and geomorphology of regressive glacigenic deltas, controlled by rapid high-Amplitude base-level change. These systems are excellent field example to test the effect of high-Amplitude base-level change on glacigenic delta systems, because subsidence, compaction, wave or tides did not play a major role. A large data set, including outcrop data, borehole data and high-resolution shear-wave seismic sections can resolve architectural elements in the range of metres and bridge the common gap between outcrop and standard industrial compression wave seismic data. The objective of this work is to provide a synthesis of the stratigraphic architecture of regressive deltas, giving new insights into the controls on delta building and erosion processes. The emphasis is placed on the sedimentary facies associations, the correlation of seismic facies with boreholes and outcrops and the analysis of the larger scale stacking pattern of architectural elements. A new depositional model summarizing facies features, depositional processes and architectures is proposed that may add to the sequence stratigraphic interpretation of steep glacigenic delta systems, controlled by rapid base-level change. Source


Lecomte I.,University of Oslo | Polom U.,LIAG | Sauvin G.,University of Oslo | Ruud B.O.,University of Bergen | And 2 more authors.
76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 | Year: 2014

As part of the world's needs for CO2-injection test sites, the city of Longyearbyen in Svalbard is an interesting location for testing technologies related to carbon capture and storage (CCS) in a vulnerable arctic environment, being a closed energy system with a coal-fuelled power plant. Therefore, the University Centre in Svalbard (UNIS) established the UNIS CO2 Lab site a few km away of Longyearbyen. The local geological structures appear suited for storing CO2 at about 600-900 m depth and injection tests are carried out. Monitoring micro-seismicity during and after injection is important, but to properly analyse micro-seismicity, a good velocity model for both P-and S-wave is necessary. The top 100-m of the site, including permafrost, is however difficult to assess. In an attempt to improve the actual velocity model near the surface, a pilot study of S-wave reflection seismic was carried out in 2012 and is reported here. Despite numerous noise sources, including wind and strong surface waves, a profile acquired on a nearby filled road showed promising results, indicating very low S-wave velocity values down to 200 m/s, thus giving a much better image of the top 70-m than P-wave seismic earlier acquired. Lessons learned are given too. Source


Coscia I.,ETH Zurich | Greenhalgh S.,ETH Zurich | Green A.,ETH Zurich | Gunther T.,LIAG | And 2 more authors.
Near Surface 2010 - 16th European Meeting of Environmental and Engineering Geophysics | Year: 2010

We are using 3D time-lapse borehole electrical resistivity tomography ERT to investigate the hydrological properties of a producing aquifer in north-eastern Switzerland. During the frequent flooding of an adjacent river, relatively high-resistivity river water infiltrates the gravel aquifer. As a consequence, the electrical characteristics of the infiltrating water can be used as a natural tracer to delineate preferential flow paths through the 7 m thick aquifer. For this research we have installed eighteen monitoring boreholes that completely penetrate the underlying aquifer. Each borehole has been instrumented with 10 electrodes that span the thickness of the aquifer. A multichannel resistivity system, programmed to cycle through various four-point electrode configurations of the 180 electrodes in a rolling sequence, allows the collection of approximately 15,500 apparent resistivity measurements every seven hours on a continuous basis. Three-dimensional static ERT inversions at periods of stable hydrological conditions were carried out to investigate the resolving capability of our acquisition scheme, to define the main lithological structures within the aquifer, to study the superposed time-varying effects (e.g. water table height fluctuations, changes in salinity and temperature) on the measurements, and to provide a base model for future time-lapse inversion studies. Source


Kirsch R.,LLUR SH | Wiederhold H.,LIAG | Rabbel W.,CAU | Erkul E.,CAU | And 4 more authors.
Near Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics | Year: 2015

On the sports ground in the village of Münsterdorf small scale (about 2 m wide) sinkholes occur in a regular time interval of about 2 years. Origins of the sinkholes are cavities formed in a Cretateaous chalk layer covered by about 20 m of unconsolidated sediments. Geophysical investigations were carried out to delineate the area of sinkhole risk. Criteria were established to define sinkhole risk following the "dropout sinkhole" theory of Waltham and Fookes": a) weakened chalk surface with fissures, b) sandy layers covering the chalk surface, c) cohesive layer in the sedimentary cover leading to a "soil cavity" after sandy material is washed into the fissures of the chalk. Seismic, resitivity and GPR methods were applied in this area. In the area of sinkhole occurance reduced s-wave velocities and a diffuse reflection image of the chalk surface were found (in contrast to the clear chalk reflections outside the sinkhole area). Resistivity measurements (2D ERT and AEM) verified a sandy layer (high specific resistivity) on top of the chalk layer and a low resistivity layer (till or clay, cohesive) in the sedimentary cover. A 3D GPR survey covering the sports ground found evidence of former sinkholes in the area. © (2015) by the European Association of Geoscientists & Engineers (EAGE). Source


Reinicke K.M.,Clausthal University of Technology | Oppelt J.,Baker Hughes Inc. | Ostermeyer G.P.,TU Braunschweig | Teodoriu C.,Clausthal University of Technology | Thomas R.,LIAG
Proceedings - SPE Annual Technical Conference and Exhibition | Year: 2010

The government of Lower Saxony plans an extensive utilization of the geothermal potential in its subsurface for heat and electrical energy supply. The conditions to achieve this objective are quite favorable despite the moderate temperatures typical for the subsurface here: the geothermal potential below the surface of Lower Saxony is considerable, the knowledge of the geological subsurface in this oil and gas federal state is good, and the scientific and industrial infrastructure for exploring and developing the geologic subsurface is excellent. The gebo research association unites the traditional strengths of the participating universities of the federal state of Lower Saxony and independent research institutions in geosciences, drilling technology, materials science, and technical systems. More than 40 scientists and engineers work together to develop and evaluate new concepts, materials, and devices. The gebo research association focuses on broad-scale, partially extremely high-risk problems in the "high-end" area of geothermal research; at the same time the participating industry is carrying out applied systems developments. Besides improving the economics of geothermal energy production and making it economically attractive in Lower Saxony, significant gebo "spin-off" effects are expected to occur in industrial sectors, in particular from the materials and systems technology research. The paper focuses on the concept of technology transfer through the gebo platform, as well as on its unique cooperation between seven project partners (research institutions), the industry partner, and the state of Lower Saxony. Also, the paper describes the objective, strategy, and organization of the research program gebo, which aims at improving the economics of geothermal energy recovery from deep geological strata by investigating new concepts and basic scientific work. Copyright 2010, Society of Petroleum Engineers. Source

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