Conference Presentations by Eric Attias
"In recent years, gas hydrates deposits have attracted growing
interest from both academic and i... more "In recent years, gas hydrates deposits have attracted growing
interest from both academic and industry research, due to their potential as an unconventional energy resource, role in climate change and concern as a geohazard. The Nyegga region is located along the Norwegian west coast continental slope, featuring an extensive pockmark eld which is manifested by bathymetric troughs, seep-associated organisms, and contains rich methane-derived authigenic carbonate rocks.
In May 2012, we set out to perform the first academic controlled source electromagnetic (CSEM) experiment, along Nyegga CNE03 pockmark chimney, aiming to detect gas hydrates and free gas within the seabed. Preliminary 2D CSEM inversions were computed and analyzed for the two crossing survey lines. Initial results show a resistivity anomaly structure at the CNE03 pockmark, suggesting a 2.5 m shallow anomaly at the chimney center, likely to result from the presence of gas hydrates. Furthermore, a deeper latterly extensive 3
m anomaly emerged from the 2D inversions, most probably attributed
to the existence of a free gas layer beneath the hydrates chimney.
By applying Archie's Law, we suggest that the hydrates saturation within the CNE03 chimney pockmark is 32 %. The results of this study support previously described seismic evidences such as pulled up reflactions, high P-wave velocity and a blanking zone, which are strong indicators for the presence of hydrates at Nyegga CNE03 pockmark."
Genetics papers by Eric Attias
Experimental Physiology, 2007
Journal of Applied Physiology, 2007
RE. ACE ID genotype affects blood creatine kinase response to eccentric exercise. tomed exercise ... more RE. ACE ID genotype affects blood creatine kinase response to eccentric exercise. tomed exercise may cause muscle breakdown with marked increase in serum creatine kinase (CK) activity. The skeletal muscle reninangiotensin system (RAS) plays an important role in exercise metabolism and tissue injury. A functional insertion (I)/deletion (D) polymorphism in the angiotensin I-converting enzyme (ACE) gene (rs4646994) has been associated with ACE activity. We hypothesized that ACE ID genotype may contribute to the wide variability in individuals' CK response to a given exercise. Young individuals performed maximal eccentric contractions of the elbow flexor muscles. Pre-and postexercise CK activity was determined. ACE genotype was significantly associated with postexercise CK increase and peak CK activity. Individuals harboring one or more of the I allele had a greater increase and higher peak CK values than individuals with the DD genotype. This response was dose-dependent (mean Ϯ SE U/L: II, 8,882 Ϯ 2,362; ID, 4,454 Ϯ 1,105; DD, 2,937 Ϯ 753, ANOVA, P ϭ 0.02; P ϭ 0.009 for linear trend). Multivariate stepwise regression analysis, which included age, sex, body mass index, and genotype subtypes, revealed that ACE genotype was the most powerful independent determinant of peak CK activity (adjusted odds ratio 1.3, 95% confidence interval 1.03-1.64, P ϭ 0.02). In conclusion, we indicate a positive association of the ACE ID genotype with CK response to strenuous exercise. We suggest that the II genotype imposes increased risk for developing muscle damage, whereas the DD genotype may have protective effects. These findings support the role of local RAS in the regulation of exertional muscle injury.
Cardiology, 2009
Angiotensin II plays a key role in the pathophysiology of heart failure (HF). This study examined... more Angiotensin II plays a key role in the pathophysiology of heart failure (HF). This study examined the angiotensin II type 1 receptor (AT1R) polymorphism in patients with systolic HF and its relation to clinical manifestations and patient outcome. We genotyped 134 patients with HF and reduced systolic function for the AT1R A1166C genotype using polymerase chain reaction and restriction fragment length polymorphism. We analyzed the relationship between the AT1R A1166C polymorphism and clinical, electrocardiographic, echocardiographic and laboratory parameters in patients with ischemic and non-ischemic etiology and examined the relation between the AT1R genotype and long-term (30 months) patient survival. In HF patients, frequency of the AT1R 1166C allele and specifically the CC genotype was similar to the general population, but associated with an ischemic and not a non-ischemic etiology (p = 0.02). The CC genotype was associated with more advanced disease and more severe abnormalities of renal function (p = 0.008). Survival analysis showed that AT1R CC homozygous patients had significantly higher mortality (p = 0.008; adjusted odds ratio for mortality 6.35, 95% confidence interval 1.49-11.21, p = 0.01). The CC AT1R genotype was associated with poor prognostic markers and increased mortality. The findings support the principle of genome-based therapies in the future treatment of HF patients.
Papers by Eric Attias
AGU Fall Meeting 2020, Dec 16, 2020
[Invited talk] In: Joint Scientific Assembly IAGA-IASPEI 2021, 21.-27.08.2021, Virtual Conference ., 2021
Petrophysical properties of gas hydrate sediment samples that were collocated at the CNE03 pockma... more Petrophysical properties of gas hydrate sediment samples that were collocated at the CNE03 pockmark area, offshore Norway.
The presence of the Nyegga pockmark field within the gas hydrate stability field on the Norwegian... more The presence of the Nyegga pockmark field within the gas hydrate stability field on the Norwegian continental slope points to possible methane release through cold seeps. It is, however, not clear how the methane may migrate through the still existing hydrate stability zone as the gas should form new hydrate further up in the section. In an effort to better understand the physical processes and quantify the hydrate/gas distribution in the area, GEOMAR and the University of Southampton collected different types of electromagnetic data sets with different depth ranges and resolution in a region, which has been extensively covered by seismic investigation. The presence of hydrate within seafloor sediments causes an increase in both the bulk modulus, and hence the seismic velocity, and in the electrical resistivity. The presence of gas decreases seismic velocity but increases electrical resistivity. Both seismic and controlled source electromagnetic methods can and have been used to est...
Gas hydrate deposits are known to store vast amounts of methane, and occur worldwide in marine an... more Gas hydrate deposits are known to store vast amounts of methane, and occur worldwide in marine and permafrost regions. Methane emissions driven by hydrate dissociation may contribute to submarine slope failures, geohazards to deep water infrastructures, and possibly climate change. Alternatively, hydrates are perceived as a viable energy resource. These environmental and economic implications mean that gas hydrate research is of both academic and industrial interest. To determine the environmental impact or economic potential of gas hydrate accumulations in any given geologic setting with a high level of confidence, it is mandatory to acquire lithological and geophysical information for a well-constrained joint interpretation. Robust delineation and quantification of gas hydrate structures is not a trivial task, due to inherent uncertainties from the absence of information regarding the physical properties of the reservoir of interest. In this thesis, I develop a rigorous joint inte...
We present high-resolution resistivity imaging of gas hydrate pipe-like structures, as derived fr... more We present high-resolution resistivity imaging of gas hydrate pipe-like structures, as derived from marine controlled-source electromagnetic (CSEM) inversions that combine towed and ocean-bottom electric field receiver data, acquired from the Nyegga region, offshore Norway. Two-dimensional CSEM inversions applied to the towed receiver data detected four new prominent vertical resistive features that are likely gas hydrate structures, located in proximity to a major gas hydrate pipe-like structure, known as the CNE03 pockmark. The resistivity model resulting from the CSEM data inversion resolved the CNE03 hydrate structure in high resolution, as inferred by comparison to seismically constrained inversions. Our results indicate that shallow gas hydrate vertical features can be delineated effectively by inverting both ocean-bottom and towed receiver CSEM data simultaneously. The approach applied here can be utilised to map and monitor seafloor mineralisation, freshwater reservoirs, CO2 sequestration sites and near-surface geothermal systems.
Marine and Petroleum Geology, 2019
Abstract Methane emissions from gas hydrate deposits along continental margins may alter the biog... more Abstract Methane emissions from gas hydrate deposits along continental margins may alter the biogeophysical properties of marine environments, both on local and regional scales. The saturation of a gas hydrate deposit is commonly calculated using the elastic or electrical properties measured remotely or in-situ at the site of interest. Here, we used a combination of controlled-source electromagnetic (CSEM), seismic and sediment core data obtained in the Nyegga region, offshore Norway, in a joint elastic-electrical approach to quantify marine gas hydrates found within the CNE03 pockmark. Multiscale analysis of two sediment cores reveals significant differences between the CNE03 pockmark and a reference site located approximately 150 m northwest of CNE03. Gas hydrates and chemosynthetic bivalves were observed in the CNE03 sediments collected. The seismic velocity and electrical resistivity measured in the CNE03 sediment core are consistent with the P-wave velocity ( V P ) and resistivity values derived from seismic and CSEM remote sensing datasets, respectively. The V P gradually increases ( ~ 1.75–1.9 km/s) with depth within the CNE03 pipe-like structure, whereas the resistivity anomaly remains ~ 3 Ω m. A joint interpretation of the collocated seismic and CSEM data using a joint elastic-electrical effective medium model suggests that for the porosity range 0.55–0.65, the gas hydrate saturation within the CNE03 hydrate stability zone varies with depth between ~ 20 and 48%. At 0.6 porosity, the hydrate saturation within CNE03 varies between ~ 23 and 37%, whereas the weighted mean saturation is ~ 30%. Our results demonstrate that a well-constrained gas hydrate quantification can be accomplished by coupling P-wave velocity and CSEM resistivity data through joint elastic-electrical effective medium modelling. The approach applied in this study can be used as a framework to quantify hydrate in various marine sediments.
Uploads
Conference Presentations by Eric Attias
interest from both academic and industry research, due to their potential as an unconventional energy resource, role in climate change and concern as a geohazard. The Nyegga region is located along the Norwegian west coast continental slope, featuring an extensive pockmark eld which is manifested by bathymetric troughs, seep-associated organisms, and contains rich methane-derived authigenic carbonate rocks.
In May 2012, we set out to perform the first academic controlled source electromagnetic (CSEM) experiment, along Nyegga CNE03 pockmark chimney, aiming to detect gas hydrates and free gas within the seabed. Preliminary 2D CSEM inversions were computed and analyzed for the two crossing survey lines. Initial results show a resistivity anomaly structure at the CNE03 pockmark, suggesting a 2.5 m shallow anomaly at the chimney center, likely to result from the presence of gas hydrates. Furthermore, a deeper latterly extensive 3
m anomaly emerged from the 2D inversions, most probably attributed
to the existence of a free gas layer beneath the hydrates chimney.
By applying Archie's Law, we suggest that the hydrates saturation within the CNE03 chimney pockmark is 32 %. The results of this study support previously described seismic evidences such as pulled up reflactions, high P-wave velocity and a blanking zone, which are strong indicators for the presence of hydrates at Nyegga CNE03 pockmark."
Genetics papers by Eric Attias
Papers by Eric Attias
interest from both academic and industry research, due to their potential as an unconventional energy resource, role in climate change and concern as a geohazard. The Nyegga region is located along the Norwegian west coast continental slope, featuring an extensive pockmark eld which is manifested by bathymetric troughs, seep-associated organisms, and contains rich methane-derived authigenic carbonate rocks.
In May 2012, we set out to perform the first academic controlled source electromagnetic (CSEM) experiment, along Nyegga CNE03 pockmark chimney, aiming to detect gas hydrates and free gas within the seabed. Preliminary 2D CSEM inversions were computed and analyzed for the two crossing survey lines. Initial results show a resistivity anomaly structure at the CNE03 pockmark, suggesting a 2.5 m shallow anomaly at the chimney center, likely to result from the presence of gas hydrates. Furthermore, a deeper latterly extensive 3
m anomaly emerged from the 2D inversions, most probably attributed
to the existence of a free gas layer beneath the hydrates chimney.
By applying Archie's Law, we suggest that the hydrates saturation within the CNE03 chimney pockmark is 32 %. The results of this study support previously described seismic evidences such as pulled up reflactions, high P-wave velocity and a blanking zone, which are strong indicators for the presence of hydrates at Nyegga CNE03 pockmark."