Mailing Address
Paromita Deb
Geothermal Energy & Geofluids
Institute of Geophysics
NO F 61
Sonneggstrasse 5
CH-8092 Zurich Switzerland
Contact
Phone | +41 44 633 6818 |
pdeb(at)eaps.ethz.ch |
Administration
Prisca Maurantonio | |
+41 44 632 3465 | |
prisca.maurantonio@eaps.ethz.ch |
Publications
[Go to Proceedings Refereed] [Go to Proceedings Non-Refereed] [Go to Theses]
Underlined names are links to current or past GEG members
REFEREED PUBLICATIONS IN JOURNALS
8.
Birdsell, D. T., B.M. Adams, P. Deb, J.D. Ogland-Hand, J.M. Bielicki, M.R. Fleming, and M.O. Saar, Analytical solutions to evaluate the geothermal energy generation potential from sedimentary-basin reservoirs, Geothermics, 116, pp. 102843, 2024. https://doi.org/10.1016/j.geothermics.2023.102843 [Download] [View Abstract]Sedimentary basins are attractive for geothermal development due to their ubiquitous presence, high permeability, and extensive lateral extent. Geothermal energy from sedimentary basins has mostly been used for direct heating purposes due to their relatively low temperatures, compared to conventional hydrothermal systems. However, there is an increasing interest in using sedimentary geothermal energy for electric power generation due to the advances in conversion technologies using binary cycles that allow electricity generation from reservoir temperatures as low as 80 °C. This work develops and implements analytical solutions for calculating reservoir impedance, reservoir heat depletion, and wellbore heat loss in sedimentary reservoirs that are laterally extensive, homogeneous, horizontally isotropic and have uniform thickness. Reservoir impedance and wellbore heat loss solutions are combined with a power cycle model to estimate the electricity generation potential. Results from the analytical solutions are in good agreement with numerically computed reservoir models. Our results suggest that wellbore heat loss can be neglected in many cases of electricity generation calculations, depending on the reservoir transmissivity. The reservoir heat depletion solution shows how reservoir temperature and useful lifetime behave as a function of flow rate, initial heat within the reservoir, and heat conduction from the surroundings to the reservoir. Overall, our results suggest that in an exploratory sedimentary geothermal field, these analytical solutions can provide reliable first order estimations without incurring intensive computational costs.
7.
Deb, P., G. Giordano, X. Shi, F. Lucci, and C. Clauser, An approach to reconstruct the thermal history in active active magmatic systems: Implications for the Los Humeros volcanic complex, Mexico. , Geothermics, 96/102162, 2021. https://doi.org/10.1016/j.geothermics.2021.102162 [Download] [View Abstract]\(Reconstructing the thermal history in active volcanic complexes characterized by multiple magmatic events is challenging due to the limited knowledge of the nature and extent of the transient heat sources. Although understanding of the geometry and architecture of a magmatic system is of prime importance for accurate temperature assessments, it is still one of the most uncertain parameters in numerical models. In this work, we presented a methodology for thermal assessment in active volcanic systems, whereby field-based geological, geochemical and petrological data are integrated to define the transient heat sources of a magma plumbing system. This time-varying heat source conceptual model is applied in the Los Humeros Volcanic Complex, an active Quaternary caldera complex in the Trans Mexican Volcanic Belt, for evaluating the thermal footprint related to the major volcanic events. The site is characterized by two caldera-forming eruptions, the Los Humeros (164 000 years ago) and the Los Potreros (69 000 years ago) and numerous episodes of post-caldera bi-modal volcanism during Holocene period (8 000 – 3 000 years old). The transient nature of the heat sources is implemented as time-varying temperature boundary conditions and the complete temporal evolution for a period of 182 000 years is simulated in 13 modeling stages. The thermal impact due to the voluminous caldera-forming events and the later short-lived magma pockets of Holocene ages is simulated by emplacing heat sources in the numerical model distributed heterogeneously in space and active at different instants of time. The depth, volume and age of the magma pockets are constrained from geochemical, petrological, geochronological and thermo-barometric analysis of erupted material. The present temperature state obtained from this approach agrees well with the temperature data recorded in the geothermal wells. The thermal footprint of the individual volcanic events indicates that almost 80 % of the present-day thermal contribution results from the massive caldera-forming events. The post-caldera Holocene magma pockets had additionally increased temperatures locally by 10 % - 20 % depending on the volumes and ages of the magma pockets. The present-day thermal regime of the younger Holocene magma pockets suggests existence of super-hot resources at shallow depths in the southern part of the geothermal field, making it a potential site for future exploration activities.)\
6.
Deb, P., S. Salimzadeh, D. Vogler, S. Düber, C. Clauser, and R. R. Settgast, Verification of coupled hydraulic fracturing simulators using laboratory-scale experiments, Rock Mechanics and Rock Engineering, 54, pp. 2881-2902, 2021. https://doi.org/10.1007/s00603-021-02425-y [Download] [View Abstract]In this work, we aim to verify the predictions of the numerical simulators, which are used for designing field-scale hydraulic stimulation experiments. Although a strong theoretical understanding of this process has been gained over the past few decades, numerical predictions of fracture propagation in low-permeability rocks still remains a challenge. Against this background, we performed controlled laboratory-scale hydraulic fracturing experiments in granite samples, which not only provides high-quality experimental data but also a well-characterized experimental set-up. Using the experimental pressure responses and the final fracture sizes as benchmark, we compared the numerical predictions of two coupled hydraulic fracturing simulators—CSMP and GEOS. Both the simulators reproduced the experimental pressure behavior by implementing the physics of Linear Elastic Fracture Mechanics (LEFM) and lubrication theory within a reasonable degree of accuracy. The simulation results indicate that even in the very low-porosity (1–2%) and low-permeability ($10^{-18} m^2 - 10^{-19} m^2$) crystalline rocks, which are usually the target of EGS, fluid-loss into the matrix and unsaturated flow impacts the formation breakdown pressure and the post-breakdown pressure trends. Therefore, underestimation of such parameters in numerical modeling can lead to significant underestimation of breakdown pressure. The simulation results also indicate the importance of implementing wellbore solvers for considering the effect of system compressibility and pressure drop due to friction in the injection line. The varying injection rate as a result of decompression at the instant of fracture initiation affects the fracture size, while the entry friction at the connection between the well and the initial notch may cause an increase in the measured breakdown pressure.
5.
Weydt, L., A. Ramirez-Guzman, A. Pola-Villasenor, B. Lepillier, J. Kummerow, G. Mandrone, C. Comina, P. Deb, and et al., Petrophysical and mechanical rock property database of the Los Humeros and Acoculco geothermal fields (Mexico), Earth System Science Data , 13, pp. 571-598, 2020. https://doi.org/10.5194/essd-13-571-2021 [Download] [View Abstract]Petrophysical and mechanical rock properties are key parameters for the characterization of the deep subsurface in different disciplines such as geothermal heat extraction, petroleum reservoir engineering or mining. They are commonly used for the interpretation of geophysical data and the parameterization of numerical models and thus are the basis for economic reservoir assessment. However, detailed information regarding petrophysical and mechanical rock properties for each relevant target horizon is often scarce, inconsistent or distributed over multiple publications. Therefore, subsurface models are often populated with generalized or assumed values resulting in high uncertainties. Furthermore, diagenetic, metamorphic and hydrothermal processes significantly affect the physiochemical and mechanical properties often leading to high geological variability. A sound understanding of the controlling factors is needed to identify statistical and causal relationships between the properties as a basis for a profound reservoir assessment and modeling. Within the scope of the GEMex project (EU H2020, grant agreement no. 727550), which aims to develop new transferable exploration and exploitation approaches for enhanced and super-hot unconventional geothermal systems, a new workflow was applied to overcome the gap of knowledge of the reservoir properties. Two caldera complexes located in the northeastern Trans-Mexican Volcanic Belt-the Acoculco and Los Humeros caldera were selected as demonstration sites. The workflow starts with outcrop analog and reservoir core sample studies in order to define and characterize the properties of all key units from the basement to the cap rock as well as their mineralogy and geochemistry. This allows the identification of geological heterogeneities on different scales (outcrop analysis, representative rock samples, thin sections and chemical analysis) enabling a profound reservoir property prediction. More than 300 rock samples were taken from representative outcrops inside the Los Humeros and Acoculco calderas and the surrounding areas and from exhumed "fossil systems" in Las Minas and Zacatlán. Additionally, 66 core samples from 16 wells of the Los Humeros geothermal field and 8 core samples from well EAC1 of the Acoculco geothermal field were collected. Samples were analyzed for particle and bulk density, porosity, permeability, thermal conductivity, thermal diffusivity, and heat capacity, as well as ultrasonic wave velocities, magnetic susceptibility and electric resistivity. Afterwards, destructive rock mechanical tests (point load tests, uniaxial and triaxial tests) were conducted to determine tensile strength, uniaxial compressive strength, Young's modulus, Poisson's ratio, the bulk modulus, the shear modulus, fracture toughness, cohesion and the friction angle. In addition, X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed on 137 samples to provide information about the mineral assemblage, bulk geochemistry and the intensity of hydrothermal alteration. An extensive rock property database was created (Weydt et al., 2020; https://doi.org/10.25534/tudatalib-201.10), comprising 34 parameters determined on more than 2160 plugs. More than 31 000 data entries were compiled covering volcanic, sedimentary, metamorphic, and igneous rocks from different ages (Jurassic to Holocene), thus facilitating a wide field of applications regarding resource assessment, modeling and statistical analyses.
4.
Deb, P., D. Knapp, G. Marquart, C. Clauser, and E. Trumpy, Stochastic workflows for the evaluation of Enhanced Geothermal System (EGS) potential in geothermal greenfields with sparse data: the case study of Acoculco, Mexico, Geothermics, 88/101879, 2020. https://doi.org/10.1016/j.geothermics.2020.101879 [Download] [View Abstract]\(This paper presents a workflow for resource characterization and assessment of exploration geothermal fields with minimum data. Our approach utilizes stochastic methods to estimate the temperature distribution at potential target depths by focusing on the impact of uncertain input parameters such as thermal conductivity and porosity. We first perform stochastic forward simulations to determine the initial steady-state thermal field and subsequently quantify the uncertainty via a Monte Carlo approach known as Sequential Gaussian Simulation (SGSim). Next, we analyze the in-field likelihood of success for Enhanced Geothermal Systems by simulating hypothetical energy production scenarios based on existing geothermal installations. This approach is applied to the case study of a Hot Dry Rock geothermal field with two exploration wells, located in Acoculco, Mexico. Data scarcity in this field necessitates the use of stochastic methods for plausible prediction of reservoir temperature used to determine the accessible thermal power. Once reliable temperature estimates are obtained at potential target depths, we simulate production scenarios by assuming a prior successful stimulation process in the existing wells. In addition to providing preliminary estimates of thermal power for different injection/production rates, stimulated volumes and created permeability, we present the long-term impact of production on the temperature and pressure fields.)\
3.
Deb, P., S. Düber, C. Guarnieri Calo’ Carducci, and C. Clauser, Laboratory-scale hydraulic fracturing dataset for benchmarking of enhanced geothermal system simulation tools, Scientific Data, 7/220, 2020. https://doi.org/10.1038/s41597-020-0564-x [Download] [View Abstract]\(Successful design of enhanced geothermal systems (EGSs) requires accurate numerical simulation of hydraulic stimulation processes in the subsurface. To ensure correct prediction, the underlying model assumptions and constitutive relationships of simulators need to be verified against experimental datasets. With the aim of generating laboratory-scale benchmark datasets, a state-of-the-art testing facility was developed, allowing for experiments under controlled conditions. Samples of size 30 cm × 30 cm × 45 cm were subjected to confining stresses while high-pressure fluid was injected into the sample through a pre-drilled borehole, where a saw-cut notch was used to initiate a penny-shaped fracture. Fracture growth and propagation was monitored by measuring pressure data and acoustic emissions detected using 32 seismic sensors. Subsequently, samples were split along the fracture plane to outline the created fracture marked by a red-dyed injection fluid. Finally, a 2D fracture contour was generated using photogrammetry. Presented datasets, accessible via a public repository, include experiments on granite and marble samples. They can be used for verifying and improving numerical codes for field stimulation designs.)\
2.
Aguilar, A., P. Deb, and G. Izquierdo, Conceptual analysis of geothermal neighboring zones characterized with contrasting behavior: case study from a Mexican geothermal field, International Journal of Hydrology, 3/3, pp. 175-183, 2019. https://doi.org/10.15406/ijh.2019.03.00178 [Download] [View Abstract]InMexico,therearemanygeothermalfields,whicharecharacterizedbyhightemperaturebutlowpermeability.Inthisworkoneofthesefieldsisstudied,whichisaproducerwithhighenthalpybutlowmassflowproduction.ThescopeofthisworkistoanalyzetwoneighboringareasofLosHumerosgeothermalfield(LHGF);whoseperformanceiscontrasting.Accordingtoproductivitybehavior,itwasfoundthatlowpermeabilityofrockformationisrelatedwithunfavorablebalancebetweenexploitationandwaterentranceasrecharge.Analysisofstatictemperatureprofilesofsomewellsofthefieldprovidestemperaturerangebetween300and360°Catthebottom.Duringdrilling,lowfluidcirculationloss(nomorethan20m3/hr)isobservedinwellsofthisstudyzone.However,thereisamarkeddifference,inproductivecharacteristicsinwells,locatedinneighboringzone.Inthisstudy,thebehaviorofproducerwellslocatedatthewesternsideoftheunproductivezoneiscomparedwiththeunproductivewells.Themainconclusionresultingfromthisstudyisthatthepresenceofgeologicalstructuresinfluencestheproductiveorunproductivebehaviorofthewells.Asapracticalapplicationofthisstudyevaluationofstoredheatinareaofnon−producerwells,anditsrecoverythroughtheuseofnon−conventionaltechniques,isproposed.Oneofthese,arerelatedtothemethodologyofEnhancedGeothermalSystems(EGS).
1.
Weydt, L., K. Baer, C. Colombero, C. Comina, P. Deb, and et al., Outcrop analogue study to determine reservoir properties of the Los Humeros and Acoculco geothermal fields, Mexico, Advances in Geosciences , 45, pp. 281-287, 2018. https://doi.org/10.5194/adgeo-45-281-2018 [Download] [View Abstract]TheLosHumerosgeothermalsystemissteamdominatedandcurrentlyunderexplorationwith65wells(23producing).Havingtemperaturesabove380°C,thesystemischaracterizedasasuperhotgeothermalsystem(SHGS).Thedevelopmentofsuchsystemsisstillchallengingduetothehightemperaturesandaggressivereservoirfluidswhichleadtocorrosionandscalingproblems.ThegeothermalsysteminAcoculco(Puebla,Mexico;sofaronlyexploredviatwoexplorationwells)ischaracterizedbytemperaturesofapproximately300°Catadepthofabout2km.Inbothwellsnogeothermalfluidswerefound,eventhoughawell−developedfracturenetworkexists.Therefore,itisplannedtodevelopanenhancedgeothermalsystem(EGS).Forbetterreservoirunderstandingandprospectivemodeling,extensivegeological,geochemical,geophysicalandtechnicalinvestigationsareperformedwithinthescopeoftheGEMexproject.Outcropanaloguestudieshavebeencarriedoutinordertoidentifythemainfracturepattern,geometryanddistributionofgeologicalunitsintheareaandtocharacterizeallkeyunitsfromthebasementtothecaprockregardingpetro−andthermo−physicalrockpropertiesandmineralogy.Ongoinginvestigationsaimtoidentifygeologicalandstructuralheterogeneitiesondifferentscalestoenableamorereliablepredictionofreservoirproperties.Besidegeologicalinvestigations,physicalpropertiesofthereservoirfluidsaredeterminedtoimprovetheunderstandingofthehydrochemicalprocessesinthereservoirandthefluid−rockinteractions,whichaffectthereservoirrockproperties.
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PROCEEDINGS REFEREED
4.
Deb, P., D. Knapp, G. Marquart, and C. Clauser, Numerical Modeling of Production Scenarios for Engineered Geothermal System (EGS) in Acoculco, Mexico, Proceedings WGC 2020+1, 2021. [View Abstract]AcoculcohasbeenidentifiedasapotentialsiteforanEGS(Enhanced/EngineeredGeothermalSystem)inMexico.WithintheHorizon2020projectGEMex,itisinvestigatedasanexplorationfield.Inthepresentstudy,wedescribetheinitialsteady−statethermalmodelingforAcoculcousingstochasticforwardsimulations.Wefocusontheimpactofuncertaininputparameterssuchasthermalconductivityandporosityonthereservoirtemperatureatdifferenttargetdepthspriortoproduction.UncertaintyisquantifiedinaMonteCarloapproach,usingthealgorithmofSequentialGaussianSimulation(SGS).Fromthestochasticallyparametrizedmodel,weextractthemeantemperatureofourtargetreservoirrocksfromtheensemblesofpossiblerealizations.Followingthis,weanalyzethelikelihoodofsuccessofanEGSinthisfieldbyevaluatingproductionscenariosfromtwodifferenttargetreservoirrocks,skarnandgranite.Simulationsareperformedusingtheexistingwellsasageothermaldoublet.Thesesimulationsinvestigatetheimpactinthetemperatureandpressurefieldsasaresultofdifferentinjectionrates,permeability,andvolumeofstimulatedzoneforaproductionperiodof30years.Thisstudydoesnotattempttoaddressthetechnicalitiesassociatedwithdesigningastimulationconceptinthisfield,butratherfocusesontheeffectofproductiononthetemperatureandpressurefieldconsideringthatastimulationtreatmenthassuccessfullyresultedinaproductivegeothermaldoublet.
3.
Deb, P., D. Knapp, C. Clauser, and G. Montegrossi, Modeling natural steady-state of super-hot geothermal reservoir at Los hUmeros, Mexico, Proceedings EGC 2019, 2019. [View Abstract]WithintheframeworkofGEMex,aHorizon2020project(GrantAgreementNo.727550),wemodeltheinitialnaturalstateofthesuper−hotreservoirsystemofLosHumeros.Thisisachievedbysolvingtheporousflowandheattransportequationsinagridded,structural3DmodelofLosHumerosusingtheSHEMAT−Suite(SimulatorforHeatandMassTransport)software(Rathetal.,2006,Clauser,2003).Initially,weperformpurelyconductivesimulationsandcheckthesimulatedtemperaturesagainstthetemperaturesmeasuredatthewellbottoms.WetestedseveralconductivescenariostoobtainanunderstandingofthepatternofthebasalspecificheatflowundertheLosHumeroscalderacomplex.
2.
Deb, P., S. Salimzadeh, S. Dueber, and C. Clauser, Laboratory experiments and numerical simulations of hydraulic fracturing for enhanced geothermal systems, Proceedings EGC 2019/ISBN-978-2-9601946-1-6, 2019. [View Abstract]Hydraulicfracturingexperimentsareperformedonlargeigneousandmetamorphicrocksamplesofsize300mm×300mm×450mmatcontrolledconditionsinthelaboratory.Thefracturesarecreatedbyinjectinghigh−pressurefluidintotherock.Thegrowthandpropagationoffracturesandtheassociatedmicro−fracturesaremonitoredviaacousticemissiondatarecordedbytransducersattachedtothesamples.Thesedatasetsthenserveasbenchmarkdataforverifyingexistingornewhydraulicstimulationcodeswhichareusedforfield−scalestimulationdesign.
1.
Deb, P., D. Vogler, S. Dueber, P. Siebert, S. Reiche, C. Clauser, R.R. Settgast, and K. Willbrand, Laboratory Fracking Experiments for Verifying Numerical Simulation Codes, 80th EAGE Conference and Exhibition, pp. 1-4, 2018. https://doi.org/10.3997/2214-4609.201801166 [Download] [View Abstract]Carefully designed and well monitored experiments are irreplaceable when it comes to producing reliable data sets for a detailed understanding of physical processes, such as hydraulic fracturing. While such experiments provide insight into the governing physical processes, numerical simulations provide additional information on system behaviour by enabling a straightforward study of parameter sensitivity. In this study, we focus on both these aspects. We report on results from (1) a benchmark experimental facility for performing hydraulic fracturing experiments on large rock samples in the laboratory under controlled conditions and (2) numerical simulations of these experiments using programs, which, in future, may be used for designing hydraulic stimulation layouts. We conduct series of experiments in order to ensure reproducibility and accuracy of the measurements. This experimental data set is then shared with several research institutes to be used for verifying their simulation software. Results from the simulation provide further insight regarding parameters, which contribute to uncertainties during measurements. Detailed study of the sensitive parameters help us to improve our experimental set up further and to perform future experiments under even better controlled conditions.
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PROCEEDINGS NON-REFEREED
1.
Reinicke, A, P Deb, M Saar, V Zikovic, E Lassnig, M Knebel, and JJ Blangé, Novel Directional Steel Shot Drilling Technology for Short-Radius Multilaterals – Field Application and Commercial Impact, European Geosciences Union 2023, EGU23-14928, 2023. https://doi.org/https://doi.org/10.5194/egusphere-egu23-14928 [Download] [View Abstract]Please enter abstract here