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Ketzer, João MarceloORCID iD iconorcid.org/0000-0003-4796-8177
Publications (10 of 42) Show all publications
Braga, R., Iglesias, R. S., Romio, C., Praeg, D., Miller, D., Viana, A. & Ketzer, J. M. (2020). Modelling methane hydrate stability changes and gas release due to seasonal oscillations in bottom water temperatures on the Rio Grande cone, offshore southern Brazil. Marine and Petroleum Geology, 112, Article ID 104071.
Open this publication in new window or tab >>Modelling methane hydrate stability changes and gas release due to seasonal oscillations in bottom water temperatures on the Rio Grande cone, offshore southern Brazil
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2020 (English)In: Marine and Petroleum Geology, ISSN 0264-8172, E-ISSN 1873-4073, Vol. 112, article id 104071Article in journal (Refereed) Published
Abstract [en]

The stability of methane hydrates on continental margins worldwide is sensitive to changes in temperature and pressure conditions. It has been shown how gradual increases in bottom water temperatures due to ocean warming over post-glacial timescales can destabilize shallow oceanic hydrate deposits, causing their dissociation and gas release into the ocean. However, bottom water temperatures (BWT) may also vary significantly over much shorter timescales, including due to seasonal temperature oscillations of the ocean bottom currents. In this study, we investigate how a shallow methane hydrate deposit responds to seasonal BWT oscillations with an amplitude of up to 1.5 °C. We use the TOUGH + HYDRATE code to model changes in the methane hydrate stability zone (MHSZ) using data from the Rio Grande Cone, in the South Atlantic Ocean off the Brazilian coast. In all the cases studied, BWT oscillations resulted in significant gaseous methane fluxes into the ocean for up to 10 years, followed by a short period of small fluxes of gaseous methane into the ocean, until they stopped completely. On the other hand, aqueous methane was released into the ocean during the 100 years simulated, for all the cases studied. During the temperature oscillations, the MHSZ recedes continuously both horizontally and, in a smaller scale, vertically, until a permanent and a seasonal region in MHSZ are defined. Sensitivity tests were carried out for parameters of porosity, thermal conductivity and initial hydrate saturation, which were shown to play an important role on the volume of methane released into the ocean and on the time interval in which such release occurs. Overall, the results indicate that in a system with no gas recharge from the bottom, seasonal temperature oscillations alone cannot account for long-term gas release into the ocean.

Place, publisher, year, edition, pages
Elsevier, 2020
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-89898 (URN)10.1016/j.marpetgeo.2019.104071 (DOI)
Available from: 2019-11-04 Created: 2019-11-04 Last updated: 2019-11-21Bibliographically approved
Tharimela, R., Augustin, A., Ketzer, J. M., Cupertino, J., Miller, D., Viana, A. & Senger, K. (2019). 3D CSEM imaging of gas hydrates: insights from the Pelotas Basin, offshore Brazil.. Interpretation, 7(4), SH111-SH131
Open this publication in new window or tab >>3D CSEM imaging of gas hydrates: insights from the Pelotas Basin, offshore Brazil.
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2019 (English)In: Interpretation, ISSN 2324-8858, E-ISSN 2324-8866, Vol. 7, no 4, p. SH111-SH131Article in journal (Refereed) Published
Abstract [en]

Mapping of natural gas hydrate systems has been performed successfully in the past using the controlled-source electromagnetic (CSEM) method. This method relies on differentiating resistive highly saturated free gas or hydrate-bearing host sediment from a less resistive low-saturated gas or brine-bearing host sediments. Knowledge of the lateral extent and resistivity variations (and hence the saturation variations) within sediments that host hydrates is crucial to be able to accurately quantify the presence of saturated gas hydrates. A 3D CSEM survey (PUCRS14) was acquired in 2014 in the Pelotas Basin offshore Brazil, with hydrate resistivity mapping as the main objective. The survey was acquired within the context of the CONEGAS research project, which investigated the origin and distribution of gas hydrate deposits in the Pelotas Basin. We have inverted the acquired data using a proprietary 3D CSEM anisotropic inversion algorithm. Inversion was purely CSEM data driven, and we did not include any a priori information in the process. Prior to CSEM, interpretation of near-surface geophysical data including 2D seismic, sub-bottom profiler, and multibeam bathymetry data indicated possible presence of gas hydrates within features identified such as faults, chimneys, and seeps leading to pockmarks, along the bottom simulating reflector and within the gas hydrate stability zone. Upon integration of the same with CSEM-derived resistivity volume, the interpretation revealed excellent spatial correlation with many of these features. The interpretation further revealed new features with possible hydrate presence, which were previously overlooked due to a lack of a clear seismic and/or multibeam backscatter signature. In addition, features that were previously mapped as gas hydrate bearing had to be reinterpreted as residual or low-saturated gas/hydrate features, due to the lack of significant resistivity response associated with them. Furthermore, we used the inverted resistivity volume to derive the saturation volume of the subsurface using Archie’s equation.

Place, publisher, year, edition, pages
SEG Library, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-88815 (URN)10.1190/int-2018-0212.1 (DOI)000494016200013 ()
Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2019-11-21Bibliographically approved
Cedeno, D. G., Conceicao, R. V., Wilbert de Souza, M. R., Schimdt Quinteiro, R. V., Carniel, L. C., Ketzer, J. M., . . . Bruzza, E. d. (2019). An experimental study on smectites as nitrogen conveyors in subduction zones. Applied Clay Science, 168, 409-420
Open this publication in new window or tab >>An experimental study on smectites as nitrogen conveyors in subduction zones
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2019 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 168, p. 409-420Article in journal (Refereed) Published
Abstract [en]

We performed high pressure and high temperature (HPHT) experiments on NH4-doped montmorillonite (similar to 2 wt % of NH4) under pressures of 2.5, 4.0, and 7.7 GPa and temperatures from 200 to 700 degrees C. Each experiment was analyzed with XRD, FTIR, CHN elemental analysis, and SEM in order to determine the NH4-Smectite phase changes and their morphology, and the presence of ammonium in the runs. Our results show that smectite can easily transport nitrogen, speciated as ammonium (NH4+), incorporated into the smectite interlayer in mildly reducing environments to deeper levels in the Earth through cold thermal regime subduction zones. NH4-Smectite transforms into NH4-enriched micaceous phase (tobelite) through a NH4+-enriched interlayered I/S phase in relatively low pressures and temperatures (around 2.5 GPa and 500 degrees C). Tobelite is stable until more extreme conditions (7.7 GPa and 700 degrees C), together with lesser amounts of buddingtonite (an ammonium-bearing feldspar) kyanite, and garnet. Our experiments also show the effect of nitrogen in the feldspar stability, as potassic and sodic feldspar are stable up to similar to 5 GPa, while buddingtonite, is observed to be stable up to 7.7 GPa. Nitrogen can return to the surface once the stability of these nitrogen-enriched minerals is reached due to pressure or temperature increasing.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Nitrogen, Subduction zones, Ammonium, Pelagic sediments
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science, Environmental Science
Identifiers
urn:nbn:se:lnu:diva-80729 (URN)10.1016/j.clay.2018.11.006 (DOI)000455692700044 ()
Available from: 2019-02-20 Created: 2019-02-20 Last updated: 2019-02-20Bibliographically approved
Stranne, C., O’Regan, M., Jakobsson, M., Brüchert, V. & Ketzer, J. M. (2019). Can anaerobic oxidation of methane prevent seafloor gas escape in a warming climate?. Solid Earth, 10(5), 1541-1554
Open this publication in new window or tab >>Can anaerobic oxidation of methane prevent seafloor gas escape in a warming climate?
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2019 (English)In: Solid Earth, ISSN 1869-9510, E-ISSN 1869-9529, Vol. 10, no 5, p. 1541-1554Article in journal (Refereed) Published
Abstract [en]

Assessments of future climate-warming-induced seafloor methane (CH4) release rarely include anaerobic ox- idation of methane (AOM) within the sediments. Consider- ing that more than 90 % of the CH4 produced in ocean sed- iments today is consumed by AOM, this may result in sub- stantial overestimations of future seafloor CH4 release. Here, we integrate a fully coupled AOM module with a numerical hydrate model to investigate under what conditions rapid re- lease of CH4 can bypass AOM and result in significant fluxes to the ocean and atmosphere. We run a number of different model simulations for different permeabilities and maximum AOM rates. In all simulations, a future climate warming sce- nario is simulated by imposing a linear seafloor temperature increase of 3 ◦C over the first 100 years. The results presented in this study should be seen as a first step towards under- standing AOM dynamics in relation to climate change and hydrate dissociation. Although the model is somewhat poorly constrained, our results indicate that vertical CH4 migration through hydraulic fractures can result in low AOM efficien- cies. Fracture flow is the predicted mode of methane trans- port under warming-induced dissociation of hydrates on up- per continental slopes. Therefore, in a future climate warm- ing scenario, AOM might not significantly reduce methane release from marine sediments. 

Place, publisher, year, edition, pages
Copernicus GmbH, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-81673 (URN)10.5194/se-10-1541-2019 (DOI)000487701600001 ()
Funder
Swedish Research Council, 2014-478Swedish Research Council, 2018-04350
Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2019-10-11Bibliographically approved
Giongo, A., Haag, T., Medina-Silva, R., Heemann, R., Pereira, L. M., Zamberlan, P. M., . . . Ketzer, J. M. (2019). Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer. Geosciences Journal
Open this publication in new window or tab >>Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer
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2019 (English)In: Geosciences Journal, ISSN 1226-4806Article in journal (Refereed) Epub ahead of print
Abstract [en]

Deep subsurface microbial communities are more abundant in coarse-grained sedimentary rocks such as sandstones than in fine-grained mudstones. The low porosity and low permeability of mudstones are believed to restrict microbial life. Then, it is expected that distinct, isolated microbial communities may form in sandstones separated by mudstones. In this context, the connectivity between microbial communities in different sandstone units can be investigated to infer evolutionary patterns of diversification in space-time, which may potentially contribute with relevant data for analyses of hydraulic connectivity and stratigraphic correlation. In this work, we used high throughput DNA sequencing of a ribosomal 16S gene fragment to characterize the prokaryotic communities found in Permian sandstone samples of the same core that are separated by one mudstone interval, in the Charqueadas coal field, Parana Basin (Southern Brazil). Our samples were collected at ∌300 m deep, in porous sandstones separated by a thick mudstone package. Differences in the bacterial community structure between samples were observed for the classified OTUs, from phylum to genus. Molecular biology might be further applied as a possible tool to help to understand the spatial and temporal distribution of depositional facies, and the efficiency of low permeability rocks to compartmentalize reservoirs. Ongoing studies aim to extend the present investigation into further analyses regarding lateral changes in microbial communities present in the same sandstone units.

Place, publisher, year, edition, pages
Springer, 2019
National Category
Microbiology
Research subject
Ecology, Microbiology
Identifiers
urn:nbn:se:lnu:diva-90217 (URN)10.1007/s12303-019-0028-5 (DOI)000495956200001 ()
Available from: 2019-11-21 Created: 2019-11-21 Last updated: 2019-12-06
Ketzer, J. M., Praeg, D., Pivel, M., Augustin, A., Rodrigues, L. F., Viana, A. & Cupertino, J. (2019). Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin. Geosciences, 9(5), 1-11, Article ID 193.
Open this publication in new window or tab >>Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin
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2019 (English)In: Geosciences, E-ISSN 2076-3263, Vol. 9, no 5, p. 1-11, article id 193Article in journal (Refereed) Published
Abstract [en]

Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified.

Place, publisher, year, edition, pages
MDPI, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science, Environmental Science
Identifiers
urn:nbn:se:lnu:diva-82324 (URN)10.3390/geosciences9050193 (DOI)000470966100002 ()2-s2.0-85067624493 (Scopus ID)
Available from: 2019-04-28 Created: 2019-04-28 Last updated: 2019-08-29Bibliographically approved
Rodrigues, L. F., Ramos, A., de Araujo, G., Silveira, E., Ketzer, J. M. & Lourega, R. (2019). High-Pressure and Automatized System for Study of Natural Gas Hydrates. Paper presented at “European Association of Labour Economists, 30th annual conference, Lyon, France, 13-15 September 2018. Energies, 12(16), Article ID 3064.
Open this publication in new window or tab >>High-Pressure and Automatized System for Study of Natural Gas Hydrates
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2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 16, article id 3064Article in journal (Refereed) Published
Abstract [en]

Due to the declining of oil reserves in the world in the coming decades, gas hydrate (GH) is seen as the great promise to supply the planet's energy demand. With this, the importance of studying the behavior of GH, several researchers have been developing different systems that allow greater truthfulness in relation to the conditions where GH is found in nature. This work describes a new system to simulate formation (precipitation) and dissociation of GH primarily at natural conditions at deep-sea, lakes, and permafrost, but also applied for artificial gas hydrates studies (pipelines, and transport of hydrocarbons, CO2, and hydrogen). This system is fully automated and unique, allowing the simultaneous work in two independent reactors, built in Hastelloy C-22, with a capacity of 1 L and 10 L, facilitating rapid analyses when compared to higher-volume systems. The system can operate using different mixtures of gases (methane, ethane, propane, carbon dioxide, nitrogen, ammonia), high pressure (up to 200 bar) with high operating safety, temperature (-30 to 200 degrees C), pH controllers, stirring system, water and gas samplers, and hyphenated system with gas chromatograph (GC) to analyze the composition of the gases formed in the GH and was projected to possibility the visualizations of experiments (quartz windows).

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-87300 (URN)10.3390/en12163064 (DOI)000484454000027 ()2-s2.0-85070667181 (Scopus ID)
Conference
“European Association of Labour Economists, 30th annual conference, Lyon, France, 13-15 September 2018
Available from: 2019-08-09 Created: 2019-08-09 Last updated: 2019-09-26Bibliographically approved
Rodrigues, L., Ketzer, J. M., Oliveira, R., dos Santos, V., Augustin, A., Cupertino, J., . . . Dorle, W. (2019). Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil. Geosciences, 9(2), 1-15, Article ID 73.
Open this publication in new window or tab >>Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil
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2019 (English)In: Geosciences, ISSN 2076-3263, Vol. 9, no 2, p. 1-15, article id 73Article in journal (Refereed) Published
Abstract [en]

In this work, we investigated the molecular stable isotope compositions of hydrate-bound and dissolved gases in sediments of the Amazon deep-sea fan and adjacent continental slope, Foz do Amazonas Basin, Brazil. Some cores were obtained in places with active gas venting on the seafloor and, in one of the locations, the venting gas is probably associated with the dissociation of hydrates near the edge of their stability zone. Results of the methane stable isotopes (δ13C and δD) of hydrate-bound and dissolved gases in sediments for the Amazon fan indicated the dominant microbial origin of methane via carbon dioxide reduction, in which 13C and deuterium isotopes were highly depleted (δ13C and δD of −102.2% to −74.2% V-PDB and −190 to −150% V-SMOW, respectively). The combination of C1/(C2+C3) versus δ13C plot also suggested a biogenic origin for methane in all analysed samples (commonly >1000). However, a mixture of thermogenic and microbial gases was suggested for the hydrate-bound and dissolved gases in the continental slope adjacent to the Amazon fan, in which the combination of chemical and isotopic gas compositions in the C1/(C2+C3) versus δ13C plot were <100 in one of the recovered cores. Moreover, the δ13C-ethane of −30.0% indicates a thermogenic origin.

Place, publisher, year, edition, pages
MDPI, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science, Environmental Science
Identifiers
urn:nbn:se:lnu:diva-80085 (URN)10.3390/geosciences9020073 (DOI)000460761900018 ()2-s2.0-85065895893 (Scopus ID)
Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-08-29Bibliographically approved
Rodrigues, L. F., Macario, K. D., Anjos, R. M., Ketzer, J. M., Maraschin, A. J., Augustin, A. H., . . . Miller, D. J. (2019). Origin and alteration of organic matter in hydrate-bearing sediments of the Rio Grande Cone, Brazil: evidence from biological, physical, and chemical factors.. Radiocarbon, 1-10
Open this publication in new window or tab >>Origin and alteration of organic matter in hydrate-bearing sediments of the Rio Grande Cone, Brazil: evidence from biological, physical, and chemical factors.
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2019 (English)In: Radiocarbon, ISSN 0033-8222, E-ISSN 1945-5755, p. 1-10Article in journal (Refereed) Epub ahead of print
Abstract [en]

The Rio Grande Cone is a major fanlike depositional feature in the continental slope of the Pelotas Basin, Southern Brazil. Two representative sediment cores collected in the Cone area were retrieved using a piston core device. In this work, the organic matter (OM) in the sediments was characterized for a continental vs. marine origin using chemical proxies to help constrain the origin of gas in hydrates. The main contribution of OM was from marine organic carbon based on the stable carbon isotope (δ13C-org) and total organic carbon/total nitrogen ratio (TOC:TN) analyses. In addition, the 14C data showed important information about the origin of the OM and we suggest some factors that could modify the original organic matter and therefore mask the “real” 14C ages: (1) biological activity that could modify the carbon isotopic composition of bulk terrestrial organic matter values, (2) the existence of younger sediments from mass wasting deposits unconformably overlying older sediments, and (3) the deep-sediment-sourced methane contribution due to the input of “old” (>50 ka) organic compounds from migrating fluids.

Place, publisher, year, edition, pages
Cambridge University Press, 2019
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-88910 (URN)10.1017/RDC.2019.109 (DOI)
Available from: 2019-09-02 Created: 2019-09-02 Last updated: 2019-11-12
Iglesias, R. S., Ketzer, J. M., Maraschin, A. J. & Sbrissa, G. (2018). Characterization and modeling of CO2‐water‐rock interactions in Hygiene Sandstones (Upper Cretaceous), Denver Basin, aimed for carbon dioxide geological storage. Greenhouse Gases: Science and Technology, 8(4), 781-795
Open this publication in new window or tab >>Characterization and modeling of CO2‐water‐rock interactions in Hygiene Sandstones (Upper Cretaceous), Denver Basin, aimed for carbon dioxide geological storage
2018 (English)In: Greenhouse Gases: Science and Technology, E-ISSN 2152-3878, Vol. 8, no 4, p. 781-795Article in journal (Refereed) Published
Abstract [en]

Carbon capture and geological storage are among the most valuable technologies capable of reducing CO2 emissions. Long‐term interactions between CO2 and a reservoir, and the integrity of geological formations, are key factors in the selection of adequate reservoirs for permanent storage. Numerical models of CO2‐water‐rock geochemical interactions are often employed to predict the fate of CO2 stored in a reservoir over time. The Hygiene Sandstone, in the Denver Basin, Colorado, USA, is a geological formation with potential for CO2 storage, and was therefore studied in this work, in which we collected and characterized outcrop samples in order to supply the input parameters for numerical simulations. Four representative thin sections of Hygiene Sandstone outcrops were quantified in terms of detrital constituents, diagenesis, and porosity on the basis of conventional petrography. Sandstone mineralogy included, in decreasing order, quartz, K‐feldspar, muscovite, albite, illite, smectite, kaolinite, poikilotopic calcite, and siderite. Porosity ranged from 4% to 13%. A geochemical modeling study of CO2‐water‐rock interactions performed with two characterized samples and brine data from the Hygiene Sandstones, simulating reservoir conditions, suggested that the mineralogy of the sandstone is quite stable under the conditions that were tested and only minor mineralogical and porosity alterations would occur within a thousand years of storage.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-75696 (URN)10.1002/ghg.1788 (DOI)000440549700012 ()2-s2.0-85050976137 (Scopus ID)
Available from: 2018-06-12 Created: 2018-06-12 Last updated: 2019-08-29Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-4796-8177

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