| 1. |
- da S. Ramos, Alessandro, et al.
(författare)
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Comparative assessment between different sample preparation methodologies for PTGA CO2 adsorption assays—Pellet, powder, and fragment samples
- 2018
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Ingår i: Adsorption Science and Technology. - : Sage Publications. - 0263-6174 .- 2048-4038. ; 36:7-8, s. 1441-1455
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Tidskriftsartikel (refereegranskat)abstract
- The carbon dioxide sorption process at coal seams is very important for understanding the trapping mechanisms of carbon capture and storage. The gas retention capacity of coal seams can be estimated using indirect methods based on the adsorption/desorption isotherms obtained in the laboratory. However, the gas sorption capacity can be overestimated or underestimated depending on the sample preparation. This work evaluates different sample preparations and their theoretical adsorption capacity using coal samples from the Cambui coal field (Parana Basin), southern Brazil. Experiments using a thermogravimetric balance were done to calculate the theoretical adsorption capacity, while sample characterization was done through immediate analysis, elementary analysis, and mineralogical studies. The sample preparations used in this work were powder, pellets, and fragments. While the powder form presents an average behavior, without any experimental complication, the pellet is extremely sensitive to any variation in the sample preparation, such as fractures, and the fragment requires a much longer experiment time than the other sample preparations, being impracticable for some cases.
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| 2. |
- Giongo, Adriana, et al.
(författare)
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Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer
- 2020
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Ingår i: Geosciences Journal. - : Springer. - 1226-4806 .- 1598-7477. ; 24, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Iglesias, Rodrigo S., et al.
(författare)
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Carbon capture and geological storage in Brazil : an overview
- 2015
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Ingår i: Greenhouse Gases. - : Wiley-Blackwell. - 2152-3878. ; 5:2, s. 119-130
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Tidskriftsartikel (refereegranskat)abstract
- Brazil is recognized for possessing a low carbon-intensive energy matrix, with most of its power being generated from hydroelectricity. Its greenhouse gas emissions profile is dominated by deforestation and land-use change. Despite this characteristic, the country has been committed to the development of carbon capture and geological storage (CCS) research since this technology started to be recognized as a relevant solution for greenhouse gas emission reductions. This development has gained attention recently owing to the beginning of the production of pre-salt reservoirs, which may contain significant amounts of CO2 in the produced fluids. The work has been carried out mostly through the efforts of the academia and industrial enterprises. This paper presents a summary and a brief description of the recent activities being carried out by these sectors, aiming to develop and promote CCS in Brazil.
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| 4. |
- Miller, Dennis J., et al.
(författare)
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Natural gas hydrates in the Rio Grande Cone (Brazil) : A new province in the western South Atlantic
- 2015
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Ingår i: Marine and Petroleum Geology. - : Elsevier. - 0264-8172 .- 1873-4073. ; 67, s. 187-196
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Tidskriftsartikel (refereegranskat)abstract
- The Rio Grande Cone is a large-scale fanlike feature in the continental slope of the Pelotas Basin, Southern Brazil, where ubiquitous world-class bottom simulating reflectors (BSRs) are readily observed in seismic records. With the purpose of searching for natural gas hydrate deposits in the Cone area, four oceanographic cruises were carried out between May 2011 and July 2013, leading to the discovery of two pockmark fields, active faults and gas hydrates in shallow sediments. Multichannel seismic, multibeam echo sounder, side scan sonar and sub-bottom profiler records were used to map the shallow section and select sites for piston core sampling. Gas hydrates were recovered in several piston cores within muddy sediments collected inside pockmarks displaying high backscatter in the multibeam and side scan sonar data. We present two representative piston cores where numerous levels of gas hydrates occur, along with degassing features, authigenic carbonate and soupy sediments. Gas dissociated from gas hydrate samples is dominantly methane (>99.78%) with minor quantities of ethane. The chemical and isotopic compositions of the gas strongly suggest a biogenic origin for the analyzed samples. These new findings are regarded as strong enough evidence to consider the Rio Grande Cone as a new gas hydrate province. (C) 2015 Elsevier Ltd. All rights reserved.
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| 5. |
- Ramos, Alessandro da S., et al.
(författare)
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Geochemical Characterization of Irati And Palermo Formations (Parana Basin-Southern Brazil) for Shale Oil/Gas Exploration
- 2015
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Ingår i: Energy Technology. - : Wiley-Blackwell. - 2194-4288. ; 3:5, s. 481-487
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Tidskriftsartikel (refereegranskat)abstract
- Shale gas/oil currently are two of the most important unconventional energy resources. Their exploitation has caused an energy revolution in USA, and many countries are investing in it. Brazil has large areas covered with sedimentary basins, but little attention has been devoted to the study of shale containing oil and gas. The parameters analyzed and studied for geochemical data evaluation are: clay mineral identification, mineral matter analysis, elemental analysis (including total organic carbon, total carbon, H, N, and S), and the methane adsorption capacity of shale. Adsorption in Palermo Formation samples (depth 238.5m) was 13.72cm(3)g(-1) and for samples from Irati Formation (depth 218.45, 95.3, and 107.5m) 11.73, 6.17, and 4.61cm(3)g(-1).
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| 6. |
- Rodrigues, Luiz Frederico, et al.
(författare)
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The influence of methane fluxes on the sulfate/methane interface in sediments from the Rio Grande Cone Gas Hydrate Province, southern Brazil : A influência dos fluxos de metano na interface sulfato/metano em sedimentos de hidrato de gás do Cone do Rio Grande, Sul do Brasil
- 2017
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Ingår i: Brazilian Journal of Geology. - : FapUNIFESP (SciELO). - 2317-4692 .- 2317-4889. ; 47:3, s. 369-381
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Tidskriftsartikel (refereegranskat)abstract
- Much research has been published regarding the relation between major gas hydrate accumulations and the global carbon cycle. In this context, the determination of the sulfate/methane interface (SMI) depth is of primary importance in order to understand the dynamics of methane flux in the shallow section. This paper identifies the depth of the SMI in sediments based on sulfate and methane concentration profiles in cores recovered in the Rio Grande Cone Gas Hydrate Province, Pelotas Basin, southern Brazil. The shape of methane and sulfate concentration profiles in the sediments can be linked to the local methane flux rate as follows: (i) near linear, high upward-diffusing methane flux coupled with high sulfate diffusion from seawater; (ii) irregular, variable methane flux rates; and (iii) kink-type profile, which is indicative of variable rather than strictly high upward methane flux. The areas in which a high methane flux was identified are spatially associated with gas chimneys in sediments within pockmarks, whereas profiles with low methane flux are present in adjacent areas. These chimneys appear as acoustic blankings in seismic records and can therefore be mapped in subsurface. The wavy-like seismic reflection following the SMI coincides with the occurrence of authigenic carbonate nodules and concretions. In addition, high methane fluxes and the occurrence of concretions and nodules carbonates were correlated by stratigraphic position of the concretions bearing intervals and sulfate profiles
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| 7. |
- Santarosa, Cristian S., et al.
(författare)
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CO2 sequestration potential of Charqueadas coal field in Brazil
- 2013
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Ingår i: International Journal of Coal Geology. - : Elsevier. - 0166-5162 .- 1872-7840. ; 106, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- Although coal is not the primary source of energy in Brazil there is growing interest to evaluate the potential of coal from the south of the country for various activities. The I2B coal seam in the Charqueadas coal field has been considered a target for enhanced coal bed methane production and CO2 sequestration. A detailed experimental study of the samples from this seam was conducted at the NETL with assistance from the Pontificia Universidade Catolica Do Rio Grande Do Sul. Such properties as sorption capacity, internal structure of the samples, porosity and permeability were of primary interest in this characterization study. The samples used were low rank coals (high volatile bituminous and sub-bituminous) obtained from the I2B seam. It was observed that the temperature effect on adsorption capacity correlates negatively with as-received water and mineral content. Langmuir CO2 adsorption capacity of the coal samples ranged 0.61-2.09 mmol/g. The upper I2B seam appears to be overall more heterogeneous and less permeable than the lower I2B seam. The lower seam coal appears to have a large amount of micro-fractures that do not close even at 11 MPa of confining pressure. Published by Elsevier B.V.
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