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Publications (10 of 189) Show all publications
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
Ivandic, M. (2018). Monitoring CO2 saturation using time–lapse AVO analysis of 3D seismic data from the Ketzin CO2 storage pilot site, Germany. Geophysical Prospecting
Open this publication in new window or tab >>Monitoring CO2 saturation using time–lapse AVO analysis of 3D seismic data from the Ketzin CO2 storage pilot site, Germany
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2018 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478Article in journal (Refereed) Published
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-356770 (URN)10.1111/1365-2478.12666 (DOI)
Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2018-08-06
Xu, Z., Sopher, D., Juhlin, C., Han, L. & Gong, X. (2018). Radon-domain interferometric interpolation for reconstruction of the near-offset gap in marine seismic data. Journal of Applied Geophysics, 151, 125-141
Open this publication in new window or tab >>Radon-domain interferometric interpolation for reconstruction of the near-offset gap in marine seismic data
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2018 (English)In: Journal of Applied Geophysics, ISSN 0926-9851, E-ISSN 1879-1859, Vol. 151, p. 125-141Article in journal (Refereed) Published
Abstract [en]

In towed marine seismic data acquisition, a gap between the source and the nearest recording channel is typical. Therefore, extrapolation of the missing near-offset traces is often required to avoid unwanted effects in subsequent data processing steps. However, most existing interpolation methods perform poorly when extrapolating traces. Interferometric interpolation methods are one particular method that have been developed for filling in trace gaps in shot gathers. Interferometry-type interpolation methods differ from conventional interpolation methods as they utilize information from several adjacent shot records to fill in the missing traces. In this study, we aim to improve upon the results generated by conventional time-space domain interferometric interpolation by performing interferometric interpolation in the Radon domain, in order to overcome the effects of irregular data sampling and limited source-receiver aperture. We apply both time-space and Radon-domain interferometric interpolation methods to the Sigsbee2B synthetic dataset and a real towed marine dataset from the Baltic Sea with the primary aim to improve the image of the seabed through extrapolation into the near-offset gap. Radon-domain interferometric interpolation performs better at interpolating the missing near offset traces than conventional interferometric interpolation when applied to data with irregular geometry and limited source-receiver aperture. We also compare the interferometric interpolated results with those obtained using solely Radon transform (RT) based interpolation and show that interferometry-type interpolation performs better than solely RT-based interpolation when extrapolating the missing near-offset traces. After data processing, we show that the image of the seabed is improved by performing interferometry-type interpolation, especially when Radon-domain interferometric interpolation is applied.

Keywords
Interferometric interpolation, Cross-correlation, Multiple, Near-offset gap, Radon transform
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-354247 (URN)10.1016/j.jappgeo.2018.02.012 (DOI)000430903200012 ()
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29Bibliographically approved
Xu, Z., Sopher, D., Juhlin, C. & Han, L. (2018). Reconstruction of the near-offset gap in marine seismic data using seismic interferometric interpolation. Geophysical Prospecting, 66(S1), 1-26
Open this publication in new window or tab >>Reconstruction of the near-offset gap in marine seismic data using seismic interferometric interpolation
2018 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 66, no S1, p. 1-26Article in journal (Refereed) Published
Abstract [en]

In conventional seismic exploration, especially in marine seismic exploration, shot gathers with missing near-offset traces are common. Interferometric interpolation methods are one of a range of different methods that have been developed to solve this problem. Interferometric interpolation methods differ from conventional interpolation methods as they utilise information from multiples in the interpolation process. In this study, we apply both conventional interferometric interpolation (shot domain) and multi-domain interferometric interpolation (shot and receiver domain) to a synthetic and a real-towed marine dataset from the Baltic Sea with the primary aim of improving the image of the seabed by extrapolation of a near-offset gap. We utilise a matching filter after interferometric interpolation to partially mitigate artefacts and coherent noise associated with the far-field approximation and a limited recording aperture size. The results show that an improved image of the seabed is obtained after performing interferometric interpolation. In most cases, the results from multi-domain interferometric interpolation are similar to those from conventional interferometric interpolation. However, when the source-receiver aperture is limited, the multi-domain method performs better. A quantitative analysis for assessing the performance of interferometric interpolation shows that multi-domain interferometric interpolation typically performs better than conventional interferometric interpolation. We also benchmark the interpolated results generated by interferometric interpolation against those obtained using sparse recovery interpolation.

Place, publisher, year, edition, pages
WILEY, 2018
Keywords
Interferometric interpolation, Cross-correlation, Multiple, Near-offset gap, Interferometry
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-354515 (URN)10.1111/1365-2478.12599 (DOI)000428406000001 ()
Available from: 2018-07-16 Created: 2018-07-16 Last updated: 2018-07-16Bibliographically 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.

Keywords
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.

Keywords
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.

Keywords
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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2776-0846

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