Ghergut, Iulia

[["dc.bibliographiccitation.firstpage","67"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Geofluids"],["dc.bibliographiccitation.lastpage","81"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","McDermott, C. I."],["dc.contributor.author","Lodemann, M."],["dc.contributor.author","Ghergut, I."],["dc.contributor.author","Tenzer, H."],["dc.contributor.author","Sauter, M."],["dc.contributor.author","Kolditz, O."],["dc.date.accessioned","2018-11-07T10:22:27Z"],["dc.date.available","2018-11-07T10:22:27Z"],["dc.date.issued","2006"],["dc.description.abstract","The German Continental Deep Drilling Program comprising a pilot borehole down to 4000 m and a main borehole down to 9101 m in southeast Germany (KTB) is continuing to provide a unique opportunity for the identification of important factors and processes in deep-seated fluid and energy transfer. In situ stress conditions significantly impact flow, transport and exchange characteristics of fracture networks that dominate the permeability of crystalline reservoir rocks. In this paper, several scales of information are combined to present a fully three-dimensional hydraulic finite element model of the principal KTB fault zones, and linked to a geomechanical model describing the alteration of the hydraulic parameters with stress changes caused by fluid extraction. The concept of geomechanical facies is introduced to define and characterize architectural elements in the subsurface system. Evaluation of a long-term pump test in the KTB pilot hole, June 2002-July 2003, coupled with a geomechanical model gives an insight into some of the elastic and nonelastic processes controlling hydraulic transport in the basement rocks. Trends in the decline of the permeability and the degree of storage in the system could only partially be explained by elastic processes, clearly indicating the importance of nonelastic processes. A number of inelastic processes are suggested as areas for further research."],["dc.identifier.doi","10.1111/j.1468-8123.2006.00129.x"],["dc.identifier.isi","000234840900005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42280"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Blackwell Publishing"],["dc.relation.issn","1468-8115"],["dc.title","Investigation of coupled hydraulic-geomechanical processes at the KTB site: pressure-dependent characteristics of a long-term pump test and elastic interpretation using a geomechanical facies model"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","225"],["dc.bibliographiccitation.journal","Geothermics"],["dc.bibliographiccitation.lastpage","241"],["dc.bibliographiccitation.volume","63"],["dc.contributor.author","Ghergut, Julia"],["dc.contributor.author","Behrens, Horst"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T10:09:58Z"],["dc.date.available","2018-11-07T10:09:58Z"],["dc.date.issued","2016"],["dc.description.abstract","The use of artificial tracers in single-well tests in conjunction with EGS-related fracturing or stimulation of sedimentary and crystalline formations in the N-German Basin is evaluated. Conservative-tracer signal analysis is suggested as a tool to quantify individual fracture contributions to multiple-fracture discharge, and illustrated with preliminary data from the Gross Schonebeck site. The proposed approach helps to avoid investing in unnecessary wellbore completion-integrated devices used for inflow profiling, especially when the productivity of the target formation is uncertain. Conservative-tracer signal analysis is further applied to estimate the thermal-lifetime Contributions from the petrothermal and the aquifer components of a hybrid EGS developed in sedimentary formations at the Horstberg site. Long-term observation of tracer signals is recommended for both sites. (C) 2016 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.geothermics.2016.01.015"],["dc.identifier.isi","000379630900016"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39761"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1879-3576"],["dc.relation.issn","0375-6505"],["dc.title","Petrothermal and aquifer-based EGS in the Northern-German Sedimentary Basin, investigated by conservative tracers during single-well injection-flowback and production tests"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","218"],["dc.bibliographiccitation.journal","Energy Procedia"],["dc.bibliographiccitation.lastpage","225"],["dc.bibliographiccitation.volume","97"],["dc.contributor.author","Dewi, Dina S."],["dc.contributor.author","Enomayo, Augustine O."],["dc.contributor.author","Ghergut, Julia"],["dc.contributor.author","Karmakar, Shyamal"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Wagner, Bianca"],["dc.date.accessioned","2020-12-10T14:23:37Z"],["dc.date.available","2020-12-10T14:23:37Z"],["dc.date.issued","2016"],["dc.identifier.doi","10.1016/j.egypro.2016.10.059"],["dc.identifier.issn","1876-6102"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/71988"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Tracer Tests for Characterizing Malm Geothermal Reservoirs Within the German BMWi Project TRENDS: A Feasibility Study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","103129"],["dc.bibliographiccitation.journal","International Journal of Greenhouse Gas Control"],["dc.bibliographiccitation.volume","101"],["dc.contributor.author","Niemi, Auli"],["dc.contributor.author","Bensabat, Jacob"],["dc.contributor.author","Joodaki, Saba"],["dc.contributor.author","Basirat, Farzad"],["dc.contributor.author","Hedayati, Maryeh"],["dc.contributor.author","Yang, Zhibing"],["dc.contributor.author","Perez, Lily"],["dc.contributor.author","Levchenko, Stanislav"],["dc.contributor.author","Shklarnik, Alon"],["dc.contributor.author","Ronen, Rona"],["dc.contributor.author","Goren, Yoni"],["dc.contributor.author","Fagerlund, Fritjof"],["dc.contributor.author","Rasmusson, Kristina"],["dc.contributor.author","Moghadasi, Ramin"],["dc.contributor.author","Shoqeir, Jawad A.H"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Ghergut, Iulia"],["dc.contributor.author","Gouze, Philippe"],["dc.contributor.author","Freifeld, Barry"],["dc.date.accessioned","2021-04-14T08:23:26Z"],["dc.date.available","2021-04-14T08:23:26Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1016/j.ijggc.2020.103129"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/80913"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.issn","1750-5836"],["dc.title","Characterizing CO2 residual trapping in-situ by means of single-well push-pull experiments at Heletz, Israel, pilot injection site – experimental procedures and results of the experiments"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","242"],["dc.bibliographiccitation.journal","Geothermics"],["dc.bibliographiccitation.lastpage","252"],["dc.bibliographiccitation.volume","63"],["dc.contributor.author","Karmakar, Shyamal"],["dc.contributor.author","Ghergut, Julia"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T10:09:59Z"],["dc.date.available","2018-11-07T10:09:59Z"],["dc.date.issued","2016"],["dc.description.abstract","Artificial-fracture design and fracture characterization is a central aspect of many Enhanced Geothermal System (EGS) projects. The use of single well (SW) short-term tracer signals to characterize fractures at the Gross-Schonebeck EGS pilot site is explored in this paper. A certain degree of parameter interdependence in short-term flowback signals leads to ambiguity in fracture parameter inversion from measured single tracer signals. This ambiguity can, to some extent, be overcome by (a) combining different sources of information, and/or (b) using different types of tracers, such as conservative tracer pairs with different diffusivities, or tracer pairs with contrasting sorptivities on target surfaces. Fracture height is likely to be controlled by lithostratigraphy while fracture length can be determined from hydraulic monitoring (pressure signals). Since the flowback rate is known during an individual-fracture test, the unknown parameters to be inferred from tracer tests are (i) transport-effective aperture in a water fracture or (ii) fracture thickness and porosity for a gel-proppant fracture. Tracers with different sorptivity on proppant coatings and matrix rock surfaces for gel-proppant fractures, and tracers with contrasting-diffusivity or -sorptivity for a water fracture were considered. An advantage of this approach is that it requires only a very small chaser injection volume (about half of fracture volume). (C) 2015 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.geothermics.2015.08.007"],["dc.identifier.isi","000379630900017"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39762"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1879-3576"],["dc.relation.issn","0375-6505"],["dc.title","Early-flowback tracer signals for fracture characterization in an EGS developed in deep crystalline and sedimentary formations: a parametric study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","28"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","OIL GAS-EUROPEAN MAGAZINE"],["dc.bibliographiccitation.lastpage","30"],["dc.bibliographiccitation.volume","40"],["dc.contributor.author","Ghergut, J."],["dc.contributor.author","Behrens, H."],["dc.contributor.author","Sauter, M."],["dc.date.accessioned","2018-11-07T09:42:57Z"],["dc.date.available","2018-11-07T09:42:57Z"],["dc.date.issued","2014"],["dc.description.abstract","Tracer tests are indispensable for measuring fluid transport parameters that control georeservoir performance for various uses (oil/gas production, geothermal, underground gas or energy storage, waste disposal). Single-well tests are particularly attractive for obvious reasons, however tracer signal inversion from single-well tests often faces parameter ambiguity issues, because the 'push-then-pull' configuration weakens the correlation between tracer residence time and target georeservoir parameters. The article shows how dual-tracer reactivity can alleviate this problem, and restore the sensitivity of tracer signals to parameters like fluid-rock interface areas."],["dc.identifier.isi","000334573200008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34075"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Urban-verlag Gmbh"],["dc.relation.issn","0342-5622"],["dc.title","Using Tracer Reactivity to Overcome Some Dilemmas of Single-Well Tracer Test Inversion"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","65"],["dc.bibliographiccitation.issue","1-2"],["dc.bibliographiccitation.journal","Palaios"],["dc.bibliographiccitation.lastpage","77"],["dc.bibliographiccitation.volume","23"],["dc.contributor.author","Porada, Hubertus"],["dc.contributor.author","Ghergut, Iulia"],["dc.contributor.author","Bouougri, El Hafid"],["dc.date.accessioned","2018-11-07T11:20:32Z"],["dc.date.available","2018-11-07T11:20:32Z"],["dc.date.issued","2008"],["dc.description.abstract","Kinneyia structures are among the most typical wrinkle structures observed on ancient siliciclastic sediment surfaces since the Archean. Recently, Kinneyia structures have been grouped together with other microbially induced, crinkly decorations on ancient bedding surfaces as wrinkle structures. They are mainly preserved on upper surfaces of ancient siliciclastic-event deposits and are characterized by millimeter-scale, winding, flat-topped crests separated by equally sized round-bottomed troughs and pits. The structure resembles smallscale interference ripples including crest-dominated linear and pit-dominated honeycomb-like patterns. The steep slopes of the crests, however, exclude their formation at the air or water-sediment interface. Thin sections across Kinneyia structures reveal their formation beneath microbial mats. They formed at an early stage and do not arise from loading and other processes related to burial. Based on the close relationship to event deposits, a genetic model considering the specific hydraulic conditions on siliciclastic tidal flats after storms or floods is proposed. Numerical calculations show that, after microbial mats have been reestablished on the new sediment surface and groundwater is still flowing downslope, the top portion of the sediment confined beneath mats may be liquefied, thus allowing grains to move with the groundwater. Oscillations of groundwater flow owing to periodic reversals of flow direction at rising tides, and a tidal signal of oscillating pore pressure may enhance formation of ripple-like structures along the boundary with the overlying mat. The model applies primarily to Kinneyia structures presumed to be formed beneath cohesive microbial mats in peritidal zones."],["dc.identifier.doi","10.2110/palo.2006.p06-095r"],["dc.identifier.isi","000252836000008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55560"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0883-1351"],["dc.title","Kinneyia-type wrinkle structures - Critical review and model of formation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","S0883292721000998"],["dc.bibliographiccitation.firstpage","104967"],["dc.bibliographiccitation.journal","Applied Geochemistry"],["dc.bibliographiccitation.volume","129"],["dc.contributor.author","Kölbel, Lena"],["dc.contributor.author","Ghergut, Iulia"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Kölbel, Thomas"],["dc.contributor.author","Wiegand, Bettina"],["dc.date.accessioned","2021-07-05T15:00:58Z"],["dc.date.available","2021-07-05T15:00:58Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1016/j.apgeochem.2021.104967"],["dc.identifier.pii","S0883292721000998"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/87951"],["dc.language.iso","en"],["dc.notes.intern","DOI Import DOI-Import GROB-441"],["dc.relation.issn","0883-2927"],["dc.title","Integrated approach into the characterization of the fracture network of a geothermal reservoir"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]