scholarly journals Regional Exploration and Characterisation of CO2 Storage Prospects in the Utsira-Skade Aquifer, North Viking Graben, North Sea

2021 ◽  
Vol 1 ◽  
Author(s):  
C. Lloyd ◽  
M. Huuse ◽  
B. J. Barrett ◽  
A. M. W. Newton
Keyword(s):  
North Sea ◽  
Storage Capacity ◽  
Co2 Storage ◽  
Anthropogenic Emissions ◽  
Specific Storage ◽  
Full Waveform ◽  
Thickness Variability ◽  
Total Capacity ◽  
Northern North Sea ◽  
Definition Of

Subsurface CO2 storage is considered a key element of reducing anthropogenic emissions in virtually all scenarios compatible with limiting global warming to 1.5°C. The Utsira-Skade Aquifer (Utsira, Eir and Skade Formations), northern North Sea, has been identified as a suitable reservoir. Although the overall storage capacity of the full aquifer has been estimated based on regional data, it is lacking an integrated assessment of containment and internal heterogeneity, to identify optimal areas for injection and for calculation of site-specific storage capacities. A high-resolution, broadband 3D seismic reflection dataset, full waveform inverted velocity data and 102 exploration wells are utilised to provide a catalogue of CO2 storage prospects in the northern Utsira-Skade Aquifer. This is achieved through: 1) definition of the aquifer’s spatial limits; 2) calculation of porosity distribution; 3) assessment of the extent, geomorphology, thickness variability, and containment confidence (CC) of mudstones; and 4) mapping of closures through fill-to-spill simulations. CO2 storage capacity was calculated for the prospects using two approaches; using the full reservoir thickness (FRT) beneath the closures and using only the thickness from the closure top to the spill point (TSP), i.e., within structural traps. Porosity ranges from 29 to 39% across the aquifer and is higher in the Utsira and Eir Fms. relative to the underlying Skade Fm. The mudstone separating the Skade and Eir/Utsira Fm. has a thickness > 50 m, and is a potential barrier for CO2. Other intra-aquifer mudstones were mainly interpreted to act as baffles to flow. Structural traps at the top Utsira and Skade Fms. yield fifteen prospects, with criteria of > 700 m depth and FRT storage capacity of > 5 Mt CO2. They have a combined storage capacity of 330 Mt CO2 (FRT) or 196 Mt CO2 (TSP). Five prospects have a positive CC score (total capacity: 54 Mt CO2 FRT or 39 Mt CO2 TSP). Additional storage capacity could be achieved through more detailed analysis of the seal to upgrade the CC scores, or through use of a network of the mapped closures with a fill-to-spill approach, utilising more of the aquifer.

scholarly journals Impact of CO2 mixing with trapped hydrocarbons on CO2 storage capacity and security: A case study from the Captain aquifer (North Sea)

2020 ◽  
Vol 278 ◽  
pp. 115634
Author(s):  
Saeed Ghanbari ◽  
Eric J. Mackay ◽  
Niklas Heinemann ◽  
Juan Alcalde ◽  
Alan James ◽  
...  
Keyword(s):  
North Sea ◽  
Storage Capacity ◽  
Co2 Storage

Seismic-derived geomechanical properties of potential CO2 storage reservoir and cap rock in Smeaheia area, northern North Sea

2021 ◽  
Vol 40 (4) ◽  
pp. 254-260
Author(s):  
Manzar Fawad ◽  
Md Jamilur Rahman ◽  
Nazmul Haque Mondol
Keyword(s):  
Elastic Property ◽  
North Sea ◽  
Co2 Storage ◽  
Velocity Ratio ◽  
Flow Simulation ◽  
Storage Site ◽  
Petrophysical Properties ◽  
Geomechanical Properties ◽  
Reservoir Rocks ◽  
Northern North Sea

Geologic CO2 storage site selection requires reservoir, seal, and overburden investigation to prevent injection- and storage-related risks. Three-dimensional geomechanical modeling and flow simulation are crucial to evaluate these mechanical-failure-related consequences; however, the model input parameters are limited and challenging to estimate. This study focuses on geomechanical properties extracted from seismic-derived elastic property cubes. The studied reservoirs (Middle Jurassic Sognefjord, Fensfjord, and Krossfjord formation sandstones) and cap rocks (Heather and Draupne formation shales) are located in the Smeaheia area, northern North Sea, and are evaluated for a potential CO2 storage site. From the elastic property cubes, i.e., acoustic impedance, P- to S-wave velocity ratio, and bulk density, we obtained geomechanical property cubes of Young's modulus, Poisson's ratio, shear modulus, lambda-rho, and mu-rho. Petrophysical property cubes such as porosity and shale volume were also available and were extracted from the elastic property cubes using deterministic methods. We evaluated the geomechanical properties to observe their relationship with depth, compaction/cementation, and petrophysical properties to characterize the cap and reservoir rocks. We found good coherence between the geomechanical and petrophysical properties and their relationship with compaction as a function of depth. The brittleness analyses using elastic property crossplots reveal that both the cap and reservoir rocks are mainly ductile to less ductile, posing lower fracturing risk during CO2 injection. This also indicates lower risks of associated microseismic and possible CO2 leakage.

scholarly journals The Lower Jurassic Johansen Formation, northern North Sea – Depositional model and reservoir characterization for CO2 storage

2016 ◽  
Vol 77 ◽  
pp. 1376-1401 ◽  
Author(s):  
Anja Sundal ◽  
Johan Petter Nystuen ◽  
Kari-Lise Rørvik ◽  
Henning Dypvik ◽  
Per Aagaard
Keyword(s):  
North Sea ◽  
Reservoir Characterization ◽  
Co2 Storage ◽  
Lower Jurassic ◽  
Depositional Model ◽  
Northern North Sea

Geological Characterization of CO2 Storage SitesLessons from Sleipner, Northern North Sea

2003 ◽  
pp. 321-326 ◽  
Author(s):  
R CHADWICK ◽  
P ZWEIGEL ◽  
U GREGERSEN ◽  
G KIRBY ◽  
S HOLLOWAY ◽  
...  
Keyword(s):  
North Sea ◽  
Co2 Storage ◽  
Northern North Sea

Regional seal characterisation for CO2 storage, Northern North Sea

2020 ◽  
Author(s):  
Christopher Lloyd ◽  
Mads Huuse ◽  
Bonita Barrett
Keyword(s):  
North Sea ◽  
Co2 Storage ◽  
The South ◽  
Feature Maps ◽  
Seismic Attribute ◽  
North East ◽  
The North ◽  
Attribute Analysis ◽  
Northern North Sea ◽  
Migration Pathways

<p>Estimations of CO<sub>2</sub> storage capacities for saline aquifers, particularly the Utsira Formation (northern North Sea) have previously been calculated using a variety of numerical approaches. These are mainly based off reservoir depth maps and averaged petrophysical properties. In these first-pass estimations, a thick shale succession in the overburden is assumed to form the top seal. This is unlikely to be representative of the true, regional lithological heterogeneity and 3D variability of stratigraphic architecture, which may promote CO<sub>2</sub> migration out of the reservoir during injection.</p><p>This study utilises a recently acquired regional high-resolution 3D broadband seismic dataset (37,500 km<sup>2</sup>) and >200 wells in the North Viking Graben, with the aim to fully characterise the overburden of the potential CO<sub>2</sub> reservoir (Northern Utsira Formation). The objectives are to analyse: i) the presence and spatial extent of sandstone bodies in the overburden and their connectivity with the reservoir; ii) the presence of sand-filled slope channels on the clinoform foresets that may act as migration pathways; iii) evidence of previous fluid migration through the overburden. Manual seismic interpretation and well correlation is augmented by automated horizon propagation (Palaeoscan) to map individual clinoforms across the region. This is integrated with seismic attribute analysis, frequency decomposition and automated well lithology extraction to understand regional sand distribution and feature analysis (e.g. identification of channels and their fill, and possible shallow gas).</p><p>Large fan-shaped sandstone bodies (10s km-scale) are identified in the lower foresets and bottomsets of the clinothems. In the west, these are in connection with the Utsira Fm., or separated from it by a thin (<10 m) shale layer. These sands can be both beneficial to the storage capacity by producing additional gross reservoir volume (if sealed and below the critical depth for CO<sub>2</sub>), or detrimental to it if they provide a path to bypass the Utsira Fm. top seal. In the south east, sand-filled slope channels and lobes (km-scale) are recorded in the prograding clinothems but are not observed to be in connection with the Utsira Fm. (located >100 m above top Utsira Fm.). No sand-filled channels were identified in the north east from seismic attribute analysis, however the well lithology extraction for this region contained ~3% sand, thus there is a possibility of sub-seismic resolution features. In the south, foresets directly downlap the Utsira Fm. This geometry juxtaposes several individual clinothems against the reservoir, increasing the likelihood of migration if there is sand presence. This contrasts with the scenario in the north, where the bottomset of a single clinothem disconnects the reservoir from younger clinothems and restricts potential migration.</p><p>The outcome of this study is an integration of each of the regional feature maps to generate: i) a seal thickness map between the Utsira Fm. and the first overlying sand body; ii) the first leakage risk map of the Utsira Fm. that captures geological geometry and lithology distribution. These can be incorporated into any future storage estimations and identification of potential injection sites.</p>

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