1,721,186 research outputs found
GLOGOS, A New Global Onshore Gas-Oil Seeps Dataset
No full textPetroleum seeps have historically been important drivers of global petroleum exploration. Still today they can serve as direct indicators of gas and/or
oil subsurface accumulations. In particular the assessment of the origin of seeping gas is a key task for understanding, without drilling, the subsurface
hydrocarbon potential, genesis and quality; e.g., the presence of shallow microbial gas, deeper thermogenic accumulations, the presence of oil and
non-hydrocarbon undesirable gases (CO2, N2, H2S). Seeps are then indicators of tectonic discontinuities (faults) and fractured rocks; they can also
represent geo-hazards and sources of greenhouse gas (methane) and photochemical pollutants (ethane and propane).
A new global dataset of onshore gas and oil seeps (GLOGOS) is here presented. GLOGOS includes more than 1150 seeps from 84 countries (version
August 2009), and it is continuously updated and expanded. The dataset includes geographical and gas-geochemical data (molecular and isotopic
composition of the main gases). Many seeps are recently discovered or never reported in other databases. Seeps are catalogued by country and
classified in three types: gas seeps, oil seeps and mud volcanoes. All seeps have a bibliographic or www reference. GLOGOS is a unique tool for
hydrocarbon exploration, assessment of Total Petroleum Systems and geo- structural studies.PublishedArticle #700716A. Geochimica per l'ambiente e geologia medicaN/A or not JCRope
Natural emissions of methane from geological seepage in Europe
No full textRecent studies have shown that geological emissions of methane are an important greenhouse-gas source. Remarkable amounts
of methane, estimated in the order of 40-60 Tg yr-1, are naturally released into the atmosphere from the Earth’s crust through faults and fractured rocks. The main source is natural gas, both microbial and thermogenic, produced in hydrocarbon-prone sedimentary basins and injected into the atmosphere through macro-seeps (onshore and offshore mud volcanoes and other seeps) and microseepage, an invisible but pervasive flux from the soil. This source is now evaluated for Europe on the basis of a literature survey, new field measurements and derived emission factors. The up-scaling criteria recommended by the EMEP/CORINAIR guidelines are applied to the local point and area source data.
In Europe, 25 countries host oil and/or natural gas reservoirs and potentially, or actually, emit geological methane. Flux data,
however, are available only from 10 countries: the onshore or offshore petroliferous sectors of Denmark, Italy, Greece, Romania, Spain, Switzerland, United Kingdom and Black Sea countries (Bulgaria, Ukraine, Georgia). Azerbaijan, whose emissions due to mud volcanism are known to be relevant, is included in the estimate.
The sum of emissions, regional estimates and local measurements, related to macro-seeps leads to a conservative total value of
about 2.2 Tg yr-1. Together with the potential microseepage fluxes from the petroliferous basins, estimated on the basis of the Total Petroleum System concept (around 0.8 Tg yr-1), the total European seepage is projected to 3 Tg yr-1. This preliminary figure would represent, in terms of magnitude, the second natural methane source for Europe after wetlands. The estimate will have to be refined by increasing the number of seepage measurements both on lands, where there is high potential for microseepage (e.g., Germany, Hungary, Romania, Ukraine, Belarus, Russia, Georgia) and in coastal marine areas (the North Sea, the Black Sea, offshore Greece and Italy) where emission factors and the extent of the underwater seeping area are not completely known.Published1430-14434.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalreserve
‘‘Pieve Santo Stefano’’ is not a mud volcano: Comment on ‘‘Structural controls on a carbon dioxide-driven mud volcano field in the Northern Apennines’’ (by Bonini, 2009)
No full textBonini (2009) has recently written an interesting paper dealing with the structural setting and relationships to seismicity of a CO2(carbon dioxide)-driven mud volcano, called Pieve S. Stefano (PSS),
located in the Northern Apennines of Italy.We outline here that PSS is not a mud volcano at all. The author erroneously attributes the term ‘‘mud volcano’’ (also featured in the title of the article) to
a CO2-dominant gas manifestation, which should be considered as a ‘‘mofette’’ or more generally a dry CO2-vent (or ‘‘gas pool’’; Minissale et al., 2000; Heinicke et al., 2006). Our comment does not dispute Bonini’s data interpretations and conclusions (for which a first comment has already been made by Collettini, in press), but discusses why misuse of the term ‘‘mud volcano’’ may lead to misquotations in future mud volcano literature.Published1270-12714.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalreserve
Methane uncovered
No full textMethane emissions from natural gas reservoirs have long been largely overlooked. The discovery of abundant
geological gas seeps in areas of cryosphere degradation highlights the relevance of these emissions to the greenhouse gas budget.Published373-3744.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalrestricte
Geofluids and natural gas in Romania, and the 10th International Conference on Gas Geochemistry
No full textThis thematic issue of Geofluids includes 11 papers representing the three main topics discussed in the 10th edition
of the International Conference on Gas Geochemistry (ICGG-10): (i) gas in petroleum systems and seepage,
(ii) gas in geothermal systems and volcanoes and (iii) gas, seismicity and geohazards. ICGG-10 was held in 2009
in Romania, a country extraordinarily rich in surface gas manifestations, that offers innumerable opportunities for
innovative studies on gas geochemistry. We briefly describe the present knowledge on gases occurring both in
petroliferous sedimentary basins and geothermal areas of Romania. The 11 contributions of this special issue,
which include data from eight countries, are then summarised. Based on these papers and other works presented
at the ICGG-10, we find that significant advances in analytical capabilities, data treating and interpretation have
led to innovative insights into the origin, distribution and environmental impact of gases migrating to the Earth’s
surface. It is increasingly clear, in particular, that gas geochemistry can be more effective for petroleum exploration,
volcano-tectonic, geodynamic and environmental studies, if multiparametric studies are performed and the
data are interpreted in the geological context.Published457-4624.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalrestricte
GEM—Geologic Emissions of Methane, the missing source in the atmospheric methane budget
No full textCentral to any study of climate change is the
development of an inventory that identifies and quantifies natural and anthropogenic sources and sinks of greenhouse gases (GHG). Recent studies have demonstrated
that geologic emissions of methane (GEM),
although not considered in the inventories of the IntergovernmentalPanel on Climate Change (IPCC), are an important GHG source. Etiope and Klusman (2002, Chemosphere 49, 777–789) documented that significant amounts of methane, produced within the Earth crust, are released naturally into the atmosphere
through faults and fractured rocks. Major GEMs are related to hydrocarbon production in sedimentary basins (biogenic and thermogenic methane), through
continuous exhalation and eruptions from more than 1200 onshore and offshore mud volcanoes (MVs), through diffuse soil microseepage, and shallow marine
seeps; secondarily, methane is released from geothermal and volcano-magmatic systems. Minor geologic sources are those related to natural exhalation from coal-bearing
rocks (influenced by mining activities), degassing from crystalline basement and mantle. While marine seeps have been studied for decades, methane flux from MVs
has been the object of detailed measurements only since 2001, when hundreds of gas flux measurements were performed from vents and soilin the main terrestrial
MVs of Europe, in Romania and Italy (Etiope et al.,2003, Geophysical Research Letters 30, 1094, doi:10.1029/2002GL016287; and references therein). In 2003 gas flux was measured in Azerbaijan, which hosts
the world’s biggest MVs and densest MV population (Etiope et al., 2004, Geology, in press). In all areas
investigated around 102–103 tons of methane per km2 are annually injected into the atmosphere. The global
estimates of GEM from MVs range from 5 to 13Tg yr-1 (Etiope and Milkov, 2004, Environmental Geology, in press).Published3099-31004.5. Degassamento naturaleJCR Journalreserve
Mud volcanoes and microseepage: the forgotten geophysical components of atmospheric methane budget
No full textMud volcanoes and microseepage are two important natural sources of atmospheric methane, controlled by neotectonics
and seismicity. Petroleum and gas reservoirs are the deep sources, and faults and fractured rocks serve
as main pathways of degassing to the atmosphere. Violent gas emissions or eruptions are generally related to
seismic activity. The global emission of methane from onshore mud volcanoes has recently been improved
thanks to new experimental data sets acquired in Europe and Azerbaijan. The global estimate of microseepage
can be now improved on the basis of new flux data and a more precise assessment of the global area in which
microseepage may occur. Despite the uncertainty of the various source strengths, the global geological methane
flux is clearly comparable to or higher than other sources or sinks considered in the tables of the Intergovernmental
Panel on Climate Change.PublishedJCR Journalope
GEM—Geologic Emissions of Methane, the missing source in the atmospheric methane budget
No full textCentral to any study of climate change is the
development of an inventory that identifies and quantifies natural and anthropogenic sources and sinks of greenhouse gases (GHG). Recent studies have demonstrated
that geologic emissions of methane (GEM),
although not considered in the inventories of the IntergovernmentalPanel on Climate Change (IPCC), are an important GHG source. Etiope and Klusman (2002, Chemosphere 49, 777–789) documented that significant amounts of methane, produced within the Earth crust, are released naturally into the atmosphere
through faults and fractured rocks. Major GEMs are related to hydrocarbon production in sedimentary basins (biogenic and thermogenic methane), through
continuous exhalation and eruptions from more than 1200 onshore and offshore mud volcanoes (MVs), through diffuse soil microseepage, and shallow marine
seeps; secondarily, methane is released from geothermal and volcano-magmatic systems. Minor geologic sources are those related to natural exhalation from coal-bearing
rocks (influenced by mining activities), degassing from crystalline basement and mantle. While marine seeps have been studied for decades, methane flux from MVs
has been the object of detailed measurements only since 2001, when hundreds of gas flux measurements were performed from vents and soilin the main terrestrial
MVs of Europe, in Romania and Italy (Etiope et al.,2003, Geophysical Research Letters 30, 1094, doi:10.1029/2002GL016287; and references therein). In 2003 gas flux was measured in Azerbaijan, which hosts
the world’s biggest MVs and densest MV population (Etiope et al., 2004, Geology, in press). In all areas
investigated around 102–103 tons of methane per km2 are annually injected into the atmosphere. The global
estimates of GEM from MVs range from 5 to 13Tg yr-1 (Etiope and Milkov, 2004, Environmental Geology, in press).Published3099-31004.5. Degassamento naturaleJCR Journalreserve
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