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Sökning: WFRF:(Ketzer João Marcelo)

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1.
  • Ketzer, João Marcelo, et al. (författare)
  • Diagenesis and Sequence Stratigraphy : an integrated approach to constrain evolution of reservoir quality in sandstones
  • 2002
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • Diagenesis and sequence stratigraphy have been formally treated as two separate disciplines in sedimentary petrology. This thesis demonstrates that synergy between these two subjects can be used to constrain evolution of reservoir quality in sandstones. Such integrated approach is possible because sequence stratigraphy provides useful information on parameters such as pore water chemistry, residence time of sediments under certain geochemistry conditions, and detrital composition, which ultimately control diagenesis of sandstones.Evidence from five case studies and from literature, enabled the development of a conceptual model for the spatial and temporal distribution of diagenetic alterations and related evolution of reservoir quality in sandstones deposited in paralic environments. Diagenetic alterations that have been constrained within the context of sequence stratigraphy include: (i) formation of kaolinite and intragranular porosity, and mechanical infiltration of clay minerals in sandstones lying at variable depths below sequence boundaries, (ii) formation of pseudomatrix and cementation by calcite, dolomite, and siderite in lag deposits at parasequence boundaries, (iii) cementation by kaolinite, pyrite, and calcite in sandstones lying in the vicinity of parasequence boundaries with coal deposits, (iv) formation of glaucony in condensed interval at parasequence boundaries, transgressive and maximum flooding surfaces, (v) formation of berthierine in fluvial-dominated deltaic deposits of the highstand systems tract, (vi) cementation by calcite in bioclastic sandstones of the transgressive systems tract, and (vii) formation of kaolinite in fluvial deposits of the lowstand systems tract. The distribution of such alterations put important constrains for the pattern of burial diagenesis (e.g., formation of chlorite, illite, quartz), related evolution of reservoir quality in sandstones, and distribution of baffles and barriers for fluid flow in the context of sequence stratigraphy.
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2.
  • Stranne, Christian, et al. (författare)
  • Can anaerobic oxidation of methane prevent seafloor gas escape in a warming climate?
  • 2019
  • Ingår i: Solid Earth. - : Copernicus GmbH. - 1869-9510 .- 1869-9529. ; 10:5, s. 1541-1554
  • Tidskriftsartikel (refereegranskat)abstract
    • 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. 
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3.
  • de Castro Araujo Moreira, Andrea Cristina, et al. (författare)
  • The first Brazilian Field Lab fully dedicated to CO2 MMV experiments : from the start-up to the initial results
  • 2014
  • Ingår i: 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12. - : Elsevier. ; , s. 6227-6238
  • Konferensbidrag (refereegranskat)abstract
    • Currently one of the main challenges in CO2 storage research is the development, testing and validation of accurate and efficient Measuring, Monitoring and Verification (MMV) techniques to be deployed at geological sequestration sites that are cost effective yet help minimize risk. This perspective motivated PETROBRAS, the National Oil Major in Brazil, through its R&D investments portfolio to prioritize research projects that would contribute to decreasing the technological gap in the area. The Company's periodic surveys indicated the lack of infrastructure, as well as expertise in CO2 MMV, as two of the most critical issues at the national level. In order to bridge that gap, initial steps were taken in 2010 for the start-up and development of the first CO2 MMV Field Lab in Brazil, fully sponsored by PETROBRAS, with a long term goal of enabling the ranking of the best, most cost-effective MMV technology alternatives to be deployed at commercial large scale CCGS sites scheduled to be installed in the country. In addition to providing basic infrastructure to carry out the CO2 injection and controlled release experiments, the facility was designed for the simultaneous testing of multiple measuring methodologies. Additional benefits of the initiative are the creation of expertise and the acceleration of the know-how in MMV in Brazil, as well as the development of a deeper and more practical knowledge of CO2 dynamics and impacts in a real world, open air scenario. Under the full support of the PETROBRAS R&D Center (CENPES), through its Climate Change Mitigation Technological Program (PROCLIMA), the Brazilian Pilot CO2 MMV Lab was made possible through a joint 4-year research Project, conceived and carried out by PETROBRAS and local academia in Brazil, in close cooperation with international experts. An overview of the Project and the multiple research areas encompassed will be presented, together with the preliminary results of the first CO2 injection campaign, which took place in 2013. (c) 2014 The Authors. Published by Elsevier
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4.
  • Medina-Silva, Renata, et al. (författare)
  • Microbiota associated with tubes of Escarpia sp. from cold seeps in the southwestern Atlantic Ocean constitutes a community distinct from that of surrounding marine sediment and water
  • 2017
  • Ingår i: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology. - 0003-6072 .- 1572-9699. ; 111:4, s. 533-550
  • Tidskriftsartikel (refereegranskat)abstract
    • As the depth increases and the light fades in oceanic cold seeps, a variety of chemosynthetic-based benthic communities arise. Previous assessments reported polychaete annelids belonging to the family Siboglinidae as part of the fauna at cold seeps, with the ‘Vestimentifera’ clade containing specialists that depend on microbial chemosynthetic endosymbionts for nutrition. Little information exists concerning the microbiota of the external portion of the vestimentiferan trunk wall. We employed 16S rDNA-based metabarcoding to describe the external microbiota of the chitin tubes from the vestimentiferan Escarpia collected from a chemosynthetic community in a cold seep area at the southwestern Atlantic Ocean. The most abundant operational taxonomic unit (OTU) belonged to the family Pirellulaceae (phylum Planctomycetes), and the second most abundant OTU belonged to the order Methylococcales (phylum Proteobacteria), composing an average of 21.1 and 15.4% of the total reads on tubes, respectively. These frequencies contrasted with those from the surrounding environment (sediment and water), where they represent no more than 0.1% of the total reads each. Moreover, some taxa with lower abundances were detected only in Escarpia tube walls. These data constitute on the first report of an epibiont microbial community found in close association with external surface of a cold-seep metazoan, Escarpia sp., from a chemosynthetic community in the southwestern Atlantic Ocean.
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5.
  • Melo, Clarissa L., et al. (författare)
  • CO2MOVE Project : The New Brazilian Field Lab Fully Dedicated to CO2 MMV Experiments
  • 2017
  • Ingår i: 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13. - : Elsevier. ; , s. 3699-3715
  • Konferensbidrag (refereegranskat)abstract
    • After the Ressacada Project experience acquired from 2011 to 2015 when PUCRS, UNESP and other institutions conducted three controlled CO2 release experiments, PETROBRAS, the national oil company that is sponsoring the project, has launched a new challenge to its partners. The company stimulated the implementation of a new Brazilian experimental site where there will be a deepening of studies in geologically more complex conditions and more challenging from a technological point of view. The choice of an area inside PUCRS campus, in Viamao - Rio Grande do Sul state, was motivated by a predominantly clay subsoil and the privileged location of the site in terms of ease logistics and security, which is required for a project of this size that houses high-tech equipment with significant cost. The CO2MOVE project started at 2015 with the subsurface characterization of the site and the assembly and manufacture of an automated system for CO2 and gas tracers with injection capacity for 5 to 50 kg/ day. Based on physical characterization studies and on numerical modeling that is being developed, the site infrastructure will be completed in the next months with the positioning of vertical injection wells, monitoring wells, and other equipment and monitoring mesh. Monitoring tools should be arranged in an area of approximately 100m(2), occupying the entire region surrounding the injection wells. Fieldwork involving CO2 injection and monitoring should have a 60 days duration of which 15 days are for preliminary surveys (pre-injection), 30 days for injection and CO2 monitoring and the last 15 days for post-injection measurements. Following this work, the collected data will be analyzed in the university labs. Similarly to Ressacada Project, this experiment will run measurements of soil CO2 flux with accumulation chambers, CO2 turbulent fluxes with Eddy Covariance, subsurface gases and groundwater monitoring, and resistivity measurements. Other monitoring methods still not tested by the research team will be held as gas tracers monitoring and laser measurements. (C) 2017 The Authors. Published by Elsevier Ltd.
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6.
  • Melo, Clarissa L., et al. (författare)
  • Integration results of soil CO2 flux and subsurface gases in the Ressacada Pilot site, Southern Brazil
  • 2017
  • Ingår i: 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13. - : Elsevier. ; , s. 3793-3804
  • Konferensbidrag (refereegranskat)abstract
    • The first CO2 monitoring field lab at the Ressacada Farm, in the Southern region of Brazil, started in 2011 and until 2015 offered an excellent opportunity to run controlled CO2 releases experiments in soil and shallow subsurface through vertical injection wells. This paper focus on the presentation and comparison of the results obtained at the last campaign realized at this site in August 2015. The results integrate a time-lapse monitoring experiment of CO2 migration in both saturated and unsaturated sand-rich sediments and soil, using soil CO2 flux measurements and subsurface gas analyses through CO2 concentrations (ppm) and carbon isotope ratios (delta C-13 of CO2). The CO2 flux results in the studied area showed an increase in the flux values according to the increasing of injection rate and along the campaign are directed to the southwest portion of the area. However, even by injecting large amounts of CO2, fluxes are greatly reduced when it rains. The gas analysis also showed an increase in CO2 concentrations according to the increasing of the injection rate mainly in the superficial levels of the monitoring wells (0.5m and 2m depth). The delta C-13 of CO2 found on the 3rd injection day showed the presence of CO2 injected and demonstrate that the sampling methodology with vacutainer vial was effective, since there is no atmospheric contamination. The correlation of isotopic analysis were consistent with the results of concentrations and CO2 fluxes and thus, it is clear that the CO2 breakthrough occurred from the 3rd day of injection, while were obtained the largest CO2 fluxes, the higher gas concentrations in the subsurface, as well as the industrial origin of delta C-13 of CO2.
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7.
  • Melo, Clarissa Lovato, et al. (författare)
  • Study of gas tracers for CO2 monitoring
  • 2014
  • Ingår i: 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12. - : Elsevier. ; , s. 3864-3868
  • Konferensbidrag (refereegranskat)abstract
    • Gas tracers have been tested libr monitoring and detecting CO, displacement in the underground and eventually leakages to the upper layers in geological storage sites. Commonly used tracers are perfluorocarbons (PFCs) and sulfur hexafluoride (SF6). In Brazil, we are canying out gas tracers studies in laboratory for further application in field test 'facilities. These experiments consist of injecting CO, with perfluorocarbon (perfluoropropane PP and pealuormethylcyclopentane PMCP) at low pressure (ca. 290 psi) in pressurized vessels with different types of sediments and soil samples. After flowing through the sample pores, the tracer is adsorbed into a capillary adsorption tube (CAT) with a specific fiber for perfluorcabon. Then, the tracer is extracted from the CAT through a Thermal Desorption System and subsequently analyzed in a Gas Chromatograph with an Electron Capture Detector (GC ECD). The objective of these experiments is to evaluate the PFCs as a monitoring tool; analyzing the tracer retention times in different sediments, as well as understanding the CATs adsorption capacity and performance. After laboratory tests, field experiments will be conducted in the course of this project. Several experiments of CO2 injection and controlled leaks will be developed in shallow vertical wells at the project site as a continuity of the experiments started at Ressacada Fann Site (Florianopolis, Brazil). The project aim is to understand the flow and dispersion of CO2 in soil and atmosphere simulating an eventual leakage from a geological reservoir using an automated system with a dedicated module for tracers injection into CO2 stream. (C) 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creavativecommons.org/licesses/by-nc-nd/3.0/). Peer-review under responsibility of the Organizing Committee of GLIGT-12
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8.
  • Oliva, Andresa, et al. (författare)
  • A comparison of three methods for monitoring CO2 migration in soil and shallow subsurface in the Ressacada Pilot site, Southern Brazil
  • 2014
  • Ingår i: 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12. - : Elsevier. ; , s. 3992-4002
  • Konferensbidrag (refereegranskat)abstract
    • In a joint R&D project under the full sponsorship of PETROBRAS, the Brazilian National Oil Company, the first CO2 monitoring field lab was started-up in Brazil in 2011. The site chosen, the Ressacada Farm, in the Southern region of the country, offered an excellent opportunity to run controlled CO2 release experiments in soil and shallow subsurface (< 3 m depth). This paper focuses on the presentation and comparison of the results obtained using electrical imaging, CO2 flux measurements and geochemical analysis of the groundwater to monitor CO2 migration in both saturated and unsaturated sand-rich sediments and soil. In 2013 a controlled release campaign was run, covering an area of approximately 6,300 m(2). Commercial food-grade gaseous carbon dioxide was continuously injected at 3 m depth for 12 days. The average injection rate was 90 g/day, totaling ca. 32kg of gas being released. The low injection rate avoided fracturing of the unconsolidated sediments composing the bulk of the local soil matrix. Monitoring techniques deployed during 30 consecutive days, including background characterization, injection and post-injection periods, were: (1) 3D electrical imaging using a Wenner array, (2) soil CO2 flux measurements using accumulation chambers, (3) water sampling and analysis, (4) 3D (tridimensional) and 4D (time-lapsed) electrical imaging covering depth levels to approximately 10 m below the surface. Water geochemical monitoring consisted of the analyses of several chemical parameters, as well as acidity and electrical conductivity in five multi-level wells (2m; 4m and 6 m depth) installed in the vicinity of the CO2 injection well. Comparison of pre- and post-injection electrical imaging shows changes in resistivity values consistent with CO(2)migration pathways. A pronounced increase in resistivity values occurred, from 1,500 ohm. m to 2,000 ohm. m, in the vicinity of the injection well. The accumulation chamber assessment show significant changes in the CO2 flux during the release experiment: maximum values detected were ca. 270 mmol/m(2)/s(during injection) as compared to background values of c.a. 34mmol/m(2)/s. The pH showed variations after CO2 injection in two monitoring wells at 2m, 4m and 6m depth. After the CO2 injection ceased, the lowest pH measured was 4.1, which represents a decrease of 0.5 relative to the background values. Slight variations in the oxidation-reduction potential (Eh) were observed near the CO2 injection well. There was a decreasing trend of this potential, especially in a monitoring well at 6m depth, ranging from 308mV to 229mV, between the background and the injection scenarios. Ppb level increments were detected in the measurements carried out for the major cations (Ca, Mg, Na, and P) and trace elements (Ag, Al, As, B, Ba, Cd, Pb, Cu, Cr, Ni, Mn, S, V, and Zn). Electrical conductivity and alkalinity, however, remained constant throughout the experiment, with values around 40 mu S.cm(-1) and 2.5 mgCaCO(3).L-1, respectively. The response to CO2 injection was not uniformly observed by the different methods deployed on site. The highest percentage change in resistivity values near the injection well occurred 5 days after the injection had started. However the highest percentage changes in the CO2 flux values occurred 9 days after the injection, 4 days after the observed changes in resistivity values. This delay is probably due to the migration time of the gas from 0.5m depth to the surface. (C) 2014 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the Organizing Committee of GHGT-12
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9.
  • Rodrigues, Luiz F, et al. (författare)
  • Origin and alteration of organic matter in hydrate-bearing sediments of the Rio Grande Cone, Brazil : evidence from biological, physical, and chemical factors.
  • 2020
  • Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 62:1, s. 197-206
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
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10.
  • Braga, R., et al. (författare)
  • Modelling methane hydrate stability changes and gas release due to seasonal oscillations in bottom water temperatures on the Rio Grande cone, offshore southern Brazil
  • 2020
  • Ingår i: Marine and Petroleum Geology. - : Elsevier. - 0264-8172 .- 1873-4073. ; 112, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
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