13 research outputs found
A regional CO 2 containment assessment of the northern Utsira Formation seal and overburden, northern North Sea
From Wiley via Jisc Publications RouterHistory: received 2020-12-31, accepted 2021-01-05, pub-electronic 2021-03-08, pub-print 2021-06Article version: VoRPublication status: PublishedFunder: Natural Environment Research Council; Id: http://dx.doi.org/10.13039/501100000270Abstract: Upscaling Carbon Capture and Storage requires identification of suitable storage sites, with robust reservoir seals. The Utsira Formation in the northern North Sea has been flagged as a target for further storage. However, there are no regional studies of seal variability addressing heterogeneities that could facilitate seal bypass. This study aims to: (a) identify, assess and map the elements that promote or restrict fluid migration, (b) develop a matrix to regionally map containment confidence (CC) and (c) rank the different areas for CO2 containment across the Utsira Formation. The seal and overburden were mapped using a highâresolution, preâstack depthâmigrated 3D broadband seismic reflection dataset and 141 exploration wells. Seal geometry, sandstone presence and sandstone connectivity in the seal and overburden were assigned relative CC scores, which were summed to map overall CC of the Utsira Fm. Indicators for shallow gas and migration were mapped and correlated with the other elements. Areas with the lowest CC are in the west of the Utsira Fm. Here, sandstones within the Seal Interval are connected through the overburden via sandy submarine fans. In the southeast, dipping stratigraphy downlaps onto the Utsira Fm., increasing the potential for connection with glaciallyâderived channelâlobe systems in the overburden. The areas with the highest CC are the central and northeast parts of the Utsira Fm., where the Seal Interval is mudstoneâdominated and parallel to the reservoir, and channelâlobe systems identified in the Overburden Interval are disconnected from the reservoir. This area coincides with a thick depocentre of the northern Utsira Fm. These results can be used to inform CO2 storage site selection and constrain future CO2 plume simulation analyses for the Utsira Fm. The CC matrix outlined here can also be adapted and applied to regionally assess the containment of other potential CO2 storage reservoirs in any setting
Quantitative analysis of a footwallâscarp degradation complex and synârift stratigraphic architecture, Exmouth Plateau, NW Shelf, offshore Australia
Interactions between footwallâ, hangingwallâ and axialâderived depositional systems make synârift stratigraphic architecture difficult to predict, and preservation of netâerosional source landscapes is limited. Distinguishing between deposits derived from faultâscarp degradation (consequent systems) and those derived from longâlived catchments beyond the fault block crest (antecedent systems) is also challenging, but important for hydrocarbon reservoir prospecting. We undertake geometric and volumetric analysis of a faultâscarp degradation complex and adjacent hangingwallâfill associated with the Thebeâ2 fault block on the Exmouth Plateau, NW Shelf, offshore Australia, using high resolution 3D seismic data. Vertical and headward erosion of the complex and fault throw are measured. Seismicâstratigraphic and seismic facies mapping allow us to constrain the spatial and architectural variability of depositional systems in the hangingwall. Footwallâderived systems interacted with hangingwallâ and axialâderived systems, through diversion around topography, interfingering or successive onlap. We calculate the volume of footwallâsourced hangingwall fans (VHW) for nine quadrants along the fault block, and compare this to the volume of material eroded from the immediately upâdip faultâscarp (VFW). This analysis highlights areas of sediment bypass (VFW > VHW) and areas fed by sediment sources beyond the degraded fault scarp (VHW > VFW). Exposure of the border fault footwall and adjacent fault terraces produced small catchments located beyond the fault block crest that fed the hangingwall basin. One source persisted throughout the main synârift episode, and its location coincided with: (a) an intraâbasin topographic high; (b) a local fault throw minimum; (c) increased vertical and headward erosion within the faultâscarp degradation complex; and (d) sustained clinoform development in the immediate hangingwall. Our novel quantitative volumetric approach to identify throughâgoing sediment input points could be applied to other rift basinâfills. We highlight implications for hydrocarbon exploration and emphasize the need to incorporate interaction of multiple sediment sources and their resultant architecture in tectonoâstratigraphic models for rift basins
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
A Workflow for Regional Exploration of Co2 Storage Sites in Saline
Regional screening for CO2 storage sites within saline aquifers can benefit from play-based, risk segment mapping approaches developed by the exploration industry. Here, we outline a regional workflow focusing on containment and capacity for identification of storage sites that can be applied to any aquifer. A case study is presented of the northern Utsira Fm. aquifer (northern North Sea). A large-scale exploration dataset is utilised, including regional 3D, depthmigrated broadband seismic reflection data, full waveform inverted velocity data, and 141 exploration wells. A containment confidence (CC) matrix is presented as an approach to assess the seal and overburden, whereby matrix elements are mapped to constrain the most secure areas of the aquifer. Seal internal geometry, sandstone presence and sandstone connectivity are elements assessed, but other elements (e.g. faulting) could also be incorporated, if applicable. A full characterisation of the aquifer that considers 3D variability of reservoir properties is performed to inform capacity estimations. We incorporate regional porosity, intra-reservoir barriers and baffles and fill-to-spill analysis to identify prospective storage sites. Finally, minimum depth (700 m), minimum capacity (5 Mt CO2) and positive CC cut-offs are applied. The optimal region for storage is in the northeast, where four prospects are identified, with a combined storage capacity of 53 Mt CO2 (using 5% storage efficiency). Additional capacity could be achieved through use of the reservoir between adjacent prospects. These prospects can be put forward for detailed appraisal. Moreover, the mapping can form the basis of static and dynamic models, well plans and mitigation options. The workflow presented provides a systematic approach for regional CO2 storage site screening that can be readily applied by geoscientists across the industry, with typical exploration-scale datasets
Synârift delta interfan successions: Archives of sedimentation and basin evolution
Models that aim to capture the interactions between sediment supply, base level and tectonism recorded in fan delta successions in rift basins have not considered the stratigraphic archive preserved in interfan areas; yet interfan stratigraphy can provide a complementary record to the fan delta axes. The exhumed EarlyâMiddle Pleistocene Kerinitis and Selinous fan deltas, in the hangingwall of the PyrgakiâMamoussia (PâM) Fault, Corinth Rift, Greece, offer an ideal laboratory for the assessment of interfan architecture. Furthermore, using the geometry of adjacent presentâday fan deltas, interfans are classified into three endâmembers. The classification is based on their lateral separation, which determines the degree of interfingering of topset, foreset and bottomset deposits. Qualitative (facies, stratal geometries, nature of key surfaces) and quantitative (stratigraphic thickness, bedding dip, palaeocurrents, breakpoint trajectories) data were collected in the field and from unmanned aerial vehicle photogrammetryâbased 3D outcrop models of the exhumed fan delta successions. The ancient KerinitisâSelinous interfan architectures record: (a) initial westward progradation of the Kerinitis fan delta into the interfan area (Phase 1), (b) subsequent progradation of the Selinous fan delta into the interfan area and asymmetric growth of both fan deltas eastward (Phase 2), (c) stratal interfingering of foresets from both systems (Phase 3), and (d) relative baseâlevel fall, erosion and reworking of sediments into the interfan area (Phases 4 and 5). The KerinitisâSelinous interfan evolution is linked to initial net subsidence of the PâM Fault (Phases 1â3) and subsequent net uplift (Phases 4 and 5) resulting from a northward shift in fault activity. The interfan area provides a more complete stratigraphic record than the proximal axial areas of the fan deltas of the early stages of basin uplift, through higher preservation potential and protracted submergence. Therefore, for the most comprehensive insight into basin evolution, interfan analysis should be undertaken in concert with analysis of the fan delta axes
Birth weight and risk of type 2 diabetes: a systematic review
Context: low birth weight is implicated as a risk factor for type 2 diabetes. However, the strength, consistency, independence, and shape of the association have not been systematically examined.Objective: to conduct a quantitative systematic review examining published evidence on the association of birth weight and type 2 diabetes in adults.Data Sources and Study Selection: relevant studies published by June 2008 were identified through literature searches using EMBASE (from 1980), MEDLINE (from 1950), and Web of Science (from 1980), with a combination of text words and Medical Subject Headings. Studies with either quantitative or qualitative estimates of the association between birth weight and type 2 diabetes were included.Data Extraction: estimates of association (odds ratio [OR] per kilogram of increase in birth weight) were obtained from authors or from published reports in models that allowed the effects of adjustment (for body mass index and socioeconomic status) and the effects of exclusion (for macrosomia and maternal diabetes) to be examined. Estimates were pooled using random-effects models, allowing for the possibility that true associations differed between populations.Data Synthesis: of 327 reports identified, 31 were found to be relevant. Data were obtained from 30 of these reports (31 populations; 6090 diabetes cases; 152 084 individuals). Inverse birth weightâtype 2 diabetes associations were observed in 23 populations (9 of which were statistically significant) and positive associations were found in 8 (2 of which were statistically significant). Appreciable heterogeneity between populations (I2 = 66%; 95% confidence interval [CI], 51%-77%) was largely explained by positive associations in 2 native North American populations with high prevalences of maternal diabetes and in 1 other population of young adults. In the remaining 28 populations, the pooled OR of type 2 diabetes, adjusted for age and sex, was 0.75 (95% CI, 0.70-0.81) per kilogram. The shape of the birth weightâtype 2 diabetes association was strongly graded, particularly at birth weights of 3 kg or less. Adjustment for current body mass index slightly strengthened the association (OR, 0.76 [95% CI, 0.70-0.82] before adjustment and 0.70 [95% CI, 0.65-0.76] after adjustment). Adjustment for socioeconomic status did not materially affect the association (OR, 0.77 [95% CI, 0.70-0.84] before adjustment and 0.78 [95% CI, 0.72-0.84] after adjustment). There was no strong evidence of publication or small study bias.Conclusion: in most populations studied, birth weight was inversely related to type 2 diabetes risk
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit
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