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Muhamad, H., Juhlin, C., Malehmir, A. & Sopher, D. (2018). Integrated interpretation of geophysical data of the Paleozoic structure in the northwestern part of the Siljan Ring impact crater, central Sweden. Journal of Applied Geophysics, 148, 201-215
Open this publication in new window or tab >>Integrated interpretation of geophysical data of the Paleozoic structure in the northwestern part of the Siljan Ring impact crater, central Sweden
2018 (English)In: Journal of Applied Geophysics, ISSN 0926-9851, E-ISSN 1879-1859, Vol. 148, p. 201-215Article in journal (Refereed) Published
Abstract [en]

The Siljan Ring impact structure is the largest known impact structure in Europe and is Late Devonian in age. It contains a central uplift that is about 20-30 km in diameter and is surrounded by a ring-shaped depression. The Siljan area is one of the few areas in Sweden where the Paleozoic sequence has not been completely eroded, making it an important location for investigation of the geological and tectonic history of Baltica during the Paleozoic. The Paleozoic strata in this area also provide insight into the complex deformation processes associated with the impact. In this study we focus on the northwestern part of the Siljan Ring, close to the town of Orsa, with the main objective of characterizing the subsurface Paleozoic succession and uppermost Precambrian crystalline rocks along a series of seismic reflection profiles, some of which have not previously been published. We combine these seismic data with gravity and magnetic data and seismic traveltime tomography results to produce an integrated interpretation of the subsurface in the area. Our interpretation shows that the Paleozoic sequence in this area is of a relatively constant thickness, with a total thickness typically between 300 and 500 m. Faulting appears to be predominantly extensional, which we interpret to have occurred during the modification stage of the impact. Furthermore, based on the geophysical data in this area, we interpret that the impact related deformation to differ in magnitude and style from other parts of the Siljan Ring.

National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-311546 (URN)10.1016/j.jappgeo.2017.10.001 (DOI)000424171900019 ()
Available from: 2016-12-28 Created: 2016-12-28 Last updated: 2018-03-28Bibliographically approved
Huang, F., Bergmann, P., Juhlin, C., Ivandic, M., Lüth, S., Ivanova, A., . . . Zhang, F. (2018). The first post-injection seismic monitor survey at the Ketzin pilot CO2 storage site: results from time-lapse analysis. Geophysical Prospecting, 66(1), 62-84
Open this publication in new window or tab >>The first post-injection seismic monitor survey at the Ketzin pilot CO2 storage site: results from time-lapse analysis
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2018 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 66, no 1, p. 62-84Article in journal (Refereed) Published
Abstract [en]

The injection of CO2 at the Ketzin pilot CO2 storage site started in June 2008 and ended in August 2013. During the 62 months of injection, a total amount of about 67 kt of CO2 was injected into a saline aquifer. A third repeat 3D seismic survey, serving as the first post-injection survey was acquired in 2015, aiming to investigate the recent movement of the injected CO2. Consistent with the previous two time-lapse surveys, a predominantly WNW migration of the gaseous CO2 plume in the up-dip direction within the reservoir is inferred in this first post-injection survey. No systematic anomalies are detected through the reservoir overburden. The extent of the CO2 plume west of the injection site is almost identical to that found in the 2012 second repeat survey (after injection of 61 kt), however there is a significant decrease in its size east of the injection site. Assessment of the CO2 plume distribution suggests that the decrease in the size of the anomaly may be due to multiple factors, such as limited vertical resolution, CO2 dissolution and CO2 diffusion, in addition to the effects of ambient noise. 4D seismic modelling based on dynamic flow simulations indicates that a dynamic balance between the newly injected CO2 after the second repeat survey and the CO2 being dissolved and diffused was reached by the time of the first post-injection survey. Considering the considerable uncertainties in CO2 mass estimation, both patchy and non-patchy saturation models for the Ketzin site were taken into consideration.

Keyword
Seismic processing, Monitoring, 3D time-lapse (4D), CO2 sequestration
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-301005 (URN)10.1111/1365-2478.12497 (DOI)000418349700006 ()
Funder
Vattenfall ABSwedish Research Council, 2010-3657
Available from: 2016-08-17 Created: 2016-08-17 Last updated: 2018-01-17Bibliographically approved
Lueth, S., Bergmann, P., Huang, F., Ivandic, M., Ivanova, A., Juhlin, C. & Kempka, T. (2017). 4D Seismic Monitoring of CO2 Storage During Injection and Post-closure at the Ketzin Pilot Site. Paper presented at 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, Lausanne, Switzerland, 14-18 November 2016.. Energy Procedia, 114, 5761-5767
Open this publication in new window or tab >>4D Seismic Monitoring of CO2 Storage During Injection and Post-closure at the Ketzin Pilot Site
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2017 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 114, p. 5761-5767Article in journal (Refereed) Published
Abstract [en]

At the Ketzin pilot site for geological CO2 storage, about 67,000 tons of CO2 were injected during the period June 2008 – August 2013. Since August 2013, the site is in its post-closure phase. Before and during the injection phase, a comprehensive monitoring programme was established. In the early post-injection phase, a majority of the monitoring activities have continued. The stepwise abandonment of the pilot site, which is planned to be accomplished in 2018, marks also the termination of most monitoring activities. Four 3D seismic surveys were acquired between 2005 and 2015 for characterizing the reservoir structure and its overburden and for monitoring the propagation of the injected CO2 in the storage formation. The first and second repeat surveys revealed the lateral extension of the CO2 plume after injecting 22 and 61 ktons, respectively. In autumn 2015, the third 3D repeat seismic survey, serving as the first post-injection survey, was acquired. The survey was acquired using the same acquisition geometry as for previous surveys, consisting of 33 templates with five receiver lines and twelve source profiles perpendicular to the receiver lines. Seismic processing of the recently acquired data has resulted in preliminary observations which can be summarized as follows: As in previous seismic repeat surveys, a clear CO2 signature is observed at the top of the storage formation. No systematic amplitude changes are observed above the reservoir which might indicate leakage. Compared to the second repeat survey acquired in 2012, the lateral extent of the CO2 plume seems to have been reduced, which may be an indication for ongoing (and relatively fast) dissolution of the CO2 in the formation brine and diffusion into very thin layers indicating pressure release.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-328323 (URN)10.1016/j.egypro.2017.03.1714 (DOI)000419147306002 ()
Conference
13th International Conference on Greenhouse Gas Control Technologies, GHGT-13, Lausanne, Switzerland, 14-18 November 2016.
Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2018-05-04Bibliographically approved
Yan, P., Garcı́a Juanatey, M. A., Kalscheuer, T., Juhlin, C., Hedin, P., Savvaidis, A., . . . Kück, J. (2017). A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information. Geophysical Journal International, 208(3), 1465-1489
Open this publication in new window or tab >>A magnetotelluric investigation of the Scandinavian Caledonides in western Jämtland, Sweden, using the COSC borehole logs as prior information
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2017 (English)In: Geophysical Journal International, ISSN 0956-540X, E-ISSN 1365-246X, Vol. 208, no 3, p. 1465-1489Article in journal (Refereed) Published
Abstract [en]

In connection with the Collisional Orogeny in the Scandinavian Caledonides (COSC) project, broad-band magnetotelluric (MT) data were acquired at 78 stations along a recent ca. 55km- long NW-SE directed reflection seismic profile (referred to as the COSC Seismic Profile; CSP), with the eastern end located similar to 30 km to the west of the orogenic Caledonian front. The MT component of the project aims at (i) delineating the highly conductive (similar to 0.1 Omega . m) alum shales that are associated with an underlying main decollement and (ii) calibrating the MT model to borehole logs. Strike and distortion analyses of the MT data show a 3-D structure in the western 10 km of the profile around the 2.5 km deep COSC-1 borehole (IGSN: ICDP5054EHW1001) and a preferred strike angle of N34 degrees E in the central and eastern parts of the profile. 2-D modelling of MT impedances was tested using different inversion schemes and parameters. To adjust the resistivity structure locally around the borehole, resistivity logging data from COSC-1 were successfully employed as prior constraints in the 2-D MT inversions. Compared with the CSP, the model inverted from the determinant impedances shows the highest level of structural similarity. A shallow resistor (> 1000 Omega . m) in the top 2-3 km depth underneath the western most 10 km of the profile around COSC-1 corresponds to a zone of high seismic reflectivity, and a boundary at less than 1 km depth where the resistivity decreases rapidly from > 100 to < 1 Omega . m in the central and eastern parts of the profile coincides with the first seismic reflections. The depth to this boundary is well constrained as shown by 1-D inversions of the MT data from five selected sites and it decreases towards the Caledonian front in the east. Underneath the easternmost part of the profile, the MT data show evidence of a second deeper conductor (resistivity < 1 Omega . m) at > 3 km depth. Based upon the COSC-1 borehole logs, the CSP reflection seismic image, and the surface geologic map, the MT resistivity models were interpreted geologically. In the vicinity of COSC-1, the resistor down to 2-3 km depth pertains to the metamorphic Middle Allochthon. The up to 1000-m-thick shallow resistor in the central and eastern parts of the profile is interpreted to overly an imbricated unit at the bottom of the Lower Allochthon that includes the alum shales. In the MT resistivity model, the 300-500 m thick imbricated unit masks the main Caledonian decollement at its bottom. A second possible interpretation, though not favoured here, is that the decollement occurs along a much deeper seismic reflection shallowing from 4.5 km depth in the west to similar to 600 m depth in the east. An additional borehole (COSC-2) is planned to penetrate the Lower Allochthon and the main decollement surface in the central part of the profile and can provide information to overcome this interpretational ambiguity. Using a synthetic study, we evaluate how resistivity logs from COSC-2 can improve the 2-D inversion model.

Keyword
Inverse theory, Downhole methods, Magnetotellurics, Continental tectonics: compressional, Europe
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-303495 (URN)10.1093/gji/ggw457 (DOI)000396818900016 ()
Funder
Swedish Research Council, 2013-5780The Geological Survey of Sweden (SGU)
Available from: 2016-09-20 Created: 2016-09-20 Last updated: 2017-04-27Bibliographically approved
Brodic, B., Malehmir, A. & Juhlin, C. (2017). Bedrock and Fracture Zone Delineation UsingDifferent Near-surface Seismic Sources. In: : . Paper presented at Near Surface Geoscience 3-7 September 2017, Malmö, Sweden. Amsterdam, Netherlands: European Association of Geoscientists and Engineers (EAGE)
Open this publication in new window or tab >>Bedrock and Fracture Zone Delineation UsingDifferent Near-surface Seismic Sources
2017 (English)Conference paper, Published paper (Other academic)
Abstract [en]

To delineate the bedrock surface and a fracture zone intersected by a well at c. 50 m depth, a seismic survey wasconducted using four different near-surface seismic sources. These were a 5-kg sledgehammer, a metal I-beamhit laterally, an accelerated weight drop and a prototype source tested for the first time called Udarnik. TheUdarnik source has two hammers whose impacts are initiated by an electromagnetic force of the stable coilexciting its inner moving part. Two hammers separated by a distance of approximately 50 cm successively hittwo contact plates mounted on the bottom of the source. The sweep length is adjustable and maximum 18 hitscan be made per second. In this study, we compare the performance of every source used and present reflectionseismic sections and tomography results from the high-fold (star-type acquisition was used) combinedlandstreamer and wireless recorder survey. Preliminary results indicate that bedrock was well delineated both ontomography results and stacked sections for all sources and some weak reflectivity is observed where thefracture zone is expected with most of the sources used showing the potential of the seismic methods forfracture zone imaging and near-surface characterization

Place, publisher, year, edition, pages
Amsterdam, Netherlands: European Association of Geoscientists and Engineers (EAGE), 2017
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-327950 (URN)10.3997/2214-4609.201702068 (DOI)
Conference
Near Surface Geoscience 3-7 September 2017, Malmö, Sweden
Projects
TRUST Geoinfra
Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2017-08-22Bibliographically approved
Brodic, B., Malehmir, A. & Juhlin, C. (2017). Delineating fracture zones using surface-tunnel-surfaceseismic data, P-S, and S-P mode conversions. Journal of Geophysical Research - Solid Earth, 122(7), 5493-5516
Open this publication in new window or tab >>Delineating fracture zones using surface-tunnel-surfaceseismic data, P-S, and S-P mode conversions
2017 (English)In: Journal of Geophysical Research - Solid Earth, ISSN 2169-9313, E-ISSN 2169-9356, Vol. 122, no 7, p. 5493-5516Article in journal (Refereed) Published
Abstract [en]

A surface-tunnel-surface seismic experiment was conducted at the Äspö Hard Rock Laboratoryto study the seismic response of major fracture systems intersecting the tunnel. A newly developedthree-component microelectromechanical sensor-based seismic landstreamer was deployed inside the noisytunnel along with conventional seismic receivers. In addition to these, wireless recorders were placed on thesurface. This combination enabled simultaneous recording of the seismic wavefield both inside the tunneland on the surface. The landstreamer was positioned between two geophone-based line segments, alongthe interval where known fracture systems intersect the tunnel. First arrival tomography produced a velocitymodel of the rock mass between the tunnel and the surface with anomalous low-velocity zones correlatingwell with locations of known fracture systems. Prominent wave mode converted direct and reflected signals,P-S and S-P waves, were observed in numerous source gathers recorded inside the tunnel. Forward traveltime and 2-D finite difference elastic modeling, based on the known geometry of the fracture systems, showthat the converted waves are generated at these systems. Additionally, the landstreamer data were used toestimate Vp/Vs, Poisson’s ratio, and seismic attenuation factors (Qp and Qs) over fracture sets that havedifferent hydraulic conductivities. The low-conductivity fracture sets have greater reductions in P wavevelocities and Poisson’s ratio and are more attenuating than the highly hydraulically conductive fracture set.Our investigations contribute to fracture zone characterization on a scale corresponding to seismicexploration wavelengths.

National Category
Geophysics
Research subject
Geophysics with specialization in Solid Earth Physics
Identifiers
urn:nbn:se:uu:diva-327949 (URN)10.1002/2017JB014304 (DOI)000409366700040 ()
Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2017-12-20Bibliographically approved
Martens, S., Hangx, S., Juhlin, C., Kuehn, M. & Kempka, T. (2017). Energy, Resources and the Environment: Meeting the challenges of the future. Paper presented at General Assembly of European-Geosciences-Union-Energy-Resources-and-Environment-Division, APR 23-28, 2017, Vienna, AUSTRIA. Energy Procedia, 125, 1-5
Open this publication in new window or tab >>Energy, Resources and the Environment: Meeting the challenges of the future
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2017 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 125, p. 1-5Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

The European Geosciences Union (EGU) brings together geoscientists from all over the world covering all disciplines of the Earth, planetary and space sciences. This geoscientific interdisciplinarity is needed to tackle the challenges of the future. One major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources in efficient and environmentally sustainable ways. This Energy Procedia issue provides an overview of the contributions of the Division on Energy, Resources & the Environment (ERE) at the EGU General Assembly 2017.

Keyword
energy, resources, environment, integrated studies, exploitation, non-carbon based energy, carbon-based energy, geo-storage, geo-materials
National Category
Energy Systems Other Environmental Engineering Ecology
Identifiers
urn:nbn:se:uu:diva-347125 (URN)10.1016/j.egypro.2017.08.301 (DOI)000419173400001 ()
Conference
General Assembly of European-Geosciences-Union-Energy-Resources-and-Environment-Division, APR 23-28, 2017, Vienna, AUSTRIA
Available from: 2018-04-06 Created: 2018-04-06 Last updated: 2018-04-06Bibliographically approved
Doughty, C., Tsang, C.-F., Rosberg, J.-E., Juhlin, C., Dobson, P. F. & Birkholzer, J. T. (2017). Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones. Hydrogeology Journal, 25(2), 501-517
Open this publication in new window or tab >>Flowing fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones
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2017 (English)In: Hydrogeology Journal, ISSN 1431-2174, E-ISSN 1435-0157, Vol. 25, no 2, p. 501-517Article in journal (Refereed) Published
Abstract [en]

Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at re, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.

Place, publisher, year, edition, pages
SPRINGER, 2017
Keyword
Hydraulic testing, Fractured rock, Hydraulic head, Well logging, Drilling
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:uu:diva-320848 (URN)10.1007/s10040-016-1497-5 (DOI)000395001300015 ()
Funder
Swedish Research Council, 2013-94
Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2018-01-13Bibliographically approved
Muhamad, H. A., Juhlin, C., Sopher, D., Lehnert, O., Arslan, A. & Meinhold, G. (2017). High-resolution seismic imaging of Paleozoic rocks in the Mora area, Siljan Ring structure, central Sweden. GFF, 139(4), 260-275
Open this publication in new window or tab >>High-resolution seismic imaging of Paleozoic rocks in the Mora area, Siljan Ring structure, central Sweden
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2017 (English)In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 139, no 4, p. 260-275Article in journal (Refereed) Published
Abstract [en]

The Late Devonian Siljan Ring structure in Sweden is the largest known impact structure in Europe. The present-day structure comprises a central dome that is about 20–30 km in diameter, which is surrounded by a ring-shaped depression. In this study, we focus on the southwestern part of the Siljan Ring with the aim to map the structure of the Paleozoic sedimentary rocks. Four 2D high-resolution seismic lines with a total length of about 3 km were acquired in the Mora area. A three component eighty-unit land streamer, combined with wireless recorders, was used for data acquisition along with a weight drop source. Processing of the data shows that clear reflections are present, but results are less distinct where external noise was present during acquisition or the maximum source-receiver offset was too short. Petrophysical measurements on core samples, core log data and a density model along one line were used to guide the interpretation of the seismic sections. These data demonstrate that fault blocks are present in the study area and that the individual blocks have been affected differently by impact-related tectonics.

National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-312020 (URN)10.1080/11035897.2017.1386712 (DOI)000416892400003 ()
Available from: 2017-01-04 Created: 2017-01-04 Last updated: 2018-03-07Bibliographically approved
Brodic, B., Malehmir, A., Bastani, M., Mehta, S., Juhlin, C., Lundberg, E. & Wang, S. (2017). Multi-component digital-based seismic landstreamer and boat-towed radio-magnetotelluric acquisition systems for improved subsurface characterization in the urban environment. First Break, 35(8), 41-47
Open this publication in new window or tab >>Multi-component digital-based seismic landstreamer and boat-towed radio-magnetotelluric acquisition systems for improved subsurface characterization in the urban environment
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2017 (English)In: First Break, ISSN 0263-5046, E-ISSN 1365-2397, Vol. 35, no 8, p. 41-47Article in journal (Other academic) Published
Abstract [en]

It is estimated that urban life will be the norm for around 60% of the world’s population by 2040, leading to a more centralized distribution of people and making the city as the main place of residence (Whiteley, 2009). This population centralization inherently implies rapidly expanding cities and imposes the need for more infrastructure within, around and between the present city boundaries. However, infrastructure projects nowadays have to follow strict civil engineering standards that require detailed knowledge of subsurface conditions during different stages of the construction processes. Since direct methods conventionally used for site characterization (e.g., drilling and/or core testing) are still relatively expensive the focus in the last two decades has been on non-invasive, geophysical methods. However, geophysical site characterization in urban areas is not an easy task owing to numerous challenges and various types of noise sources. Challenges such as electric/electromagnetic (EM) noise, pipelines and other subsurface objects (sometimes even unknown or undocumented), the inability to properly couple sensors because of pavement, traffic noises and limited space are common in urban environment. Since geophysical surveys need to be done with the least amount of disturbances to the environment, residents and traffic, new geophysical techniques for fast, non-invasive and high-resolution site characterization are needed. To overcome some of these challenges, a nationwide joint industry-academia project was launched in 2012 TUST GeoInfra, www.trust-geoinfra.se). As a component in the project, Uppsala University developed two new data acquisition systems. These are a fully digital MEMS-based (Micro-machined Electro-Mechanical Sensor) three component (3C) seismic landstreamer and a boat-towed radio-magnetotelluric (RMT) acquisition system. Both systems were specifically designed to address urban environments with the RMT system particularly aiming at efficient and cost-effective geophysical surveying on shallow-water bodies, which constitute 7% of Scandinavia. In this article, we will describe the two systems and present two case studies illustrating their potential. A number of published accounts are now available from the two systems showing what type of problems they can address (e.g., Bastani et al., 2015; Brodic et al., 2015; Malehmir et al., 2015a, 2015b, 2016a, 2016b, 2017; Dehghannejad et al., 2017; Maries et al., 2017; Mehta et al., 2017; Brodic et al., 2017).

Place, publisher, year, edition, pages
Amsterdam, Netherlands: , 2017
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-327951 (URN)
Projects
TRUST Geoinfra
Available from: 2017-08-14 Created: 2017-08-14 Last updated: 2017-12-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2776-0846

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