O. P. Wennberg, G. McQueen, P. H. Vieira de Luca, F. Lapponi, D. Hunt, A. S. Chandler, A. Waldum, G. Nery Camargo, E. Castro, L. Loures
Natural open fractures are present in sidewall cores and in whole-core samples from pre-salt reservoirs in the licence block BM-C-33 in the Campos Basin, Brazil. Open fractures are also observed in borehole image logs, and fracture densities are in general high. The highest density of open fractures is seen in the damage zones above and below larger cavities (amalgamated cavern damage zones (ACDZs)). Outside the ACDZs the fracture density is high in silicified carbonates, where it tends to increase with decreasing porosity. Clean dolomites are less fractured than the silicified interval, while the less brittle argillaceous dolomites have the lowest fracture density. Some fractures appear vuggy on borehole image logs, and fracture densities are high close to vugs and larger cavities. The positive correlation between fractures and vugs is caused by flow of dissolving fluids through open fractures, and fracturing at stress concentrations around vugs. Two major fault zones have been interpreted from borehole image logs that have damage zones with very high fracture density. The well-test permeability is much greater than the matrix permeability estimated from sidewall core and log measurements. This excess permeability is attributed to fractures, in combination with caverns and intervals with frequent vugs.
{"title":"Open fractures in pre-salt silicified carbonate reservoirs in block BM-C-33, the Outer Campos Basin, offshore Brazil","authors":"O. P. Wennberg, G. McQueen, P. H. Vieira de Luca, F. Lapponi, D. Hunt, A. S. Chandler, A. Waldum, G. Nery Camargo, E. Castro, L. Loures","doi":"10.1144/petgeo2020-125","DOIUrl":"https://doi.org/10.1144/petgeo2020-125","url":null,"abstract":"Natural open fractures are present in sidewall cores and in whole-core samples from pre-salt reservoirs in the licence block BM-C-33 in the Campos Basin, Brazil. Open fractures are also observed in borehole image logs, and fracture densities are in general high. The highest density of open fractures is seen in the damage zones above and below larger cavities (amalgamated cavern damage zones (ACDZs)). Outside the ACDZs the fracture density is high in silicified carbonates, where it tends to increase with decreasing porosity. Clean dolomites are less fractured than the silicified interval, while the less brittle argillaceous dolomites have the lowest fracture density. Some fractures appear vuggy on borehole image logs, and fracture densities are high close to vugs and larger cavities. The positive correlation between fractures and vugs is caused by flow of dissolving fluids through open fractures, and fracturing at stress concentrations around vugs. Two major fault zones have been interpreted from borehole image logs that have damage zones with very high fracture density. The well-test permeability is much greater than the matrix permeability estimated from sidewall core and log measurements. This excess permeability is attributed to fractures, in combination with caverns and intervals with frequent vugs.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42279974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michelle R. Plampin, M. Blondes, E. Sonnenthal, W. Craddock
Geological carbon sequestration (GCS) is necessary to help meet goals for emissions reduction, but groundwater contamination may occur if CO2 and/or brine were to leak out of deep storage formations into the shallow subsurface. For this study, a natural analogue was investigated: in the Virgin River Basin of SW Utah, water with moderate salinity and high CO2 concentrations is leaking upwards into shallow aquifers that contain heavy-metal-bearing concretions. The aquifer system is comprised of the Navajo and Kayenta formations, which are pervasive across southern Utah and have been considered as a potential GCS injection unit where they are sufficiently deep. Numerical models of the site were constructed based on measured water chemistry and head distributions from previous studies. Simulations were used to improve understanding of the rate and distribution of the upwelling flow into the aquifers, and to assess the reactive transport processes that may occur if the upwelling fluids were to interact with a zone of iron oxide and other heavy metals, representing the concretions that are common in the area. Various mineralogies were tested, including one in which Pb2+ was adsorbed onto ferrihydrite, and another in which it was bound within a solid mixture of litharge (PbO) and hematite (Fe2O3). Results indicate that metal mobilization depends strongly on the source-zone composition and that Pb2+ transport can be naturally attenuated by gas-phase formation and carbonate-mineral precipitation. These findings could be used to improve risk assessment and mitigation strategies at geological carbon sequestration sites. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage
{"title":"Potential Pb2+ mobilization, transport, and sequestration in shallow aquifers impacted by multiphase CO2 leakage: a natural analogue study from the Virgin River Basin in SW Utah","authors":"Michelle R. Plampin, M. Blondes, E. Sonnenthal, W. Craddock","doi":"10.1144/petgeo2020-109","DOIUrl":"https://doi.org/10.1144/petgeo2020-109","url":null,"abstract":"Geological carbon sequestration (GCS) is necessary to help meet goals for emissions reduction, but groundwater contamination may occur if CO2 and/or brine were to leak out of deep storage formations into the shallow subsurface. For this study, a natural analogue was investigated: in the Virgin River Basin of SW Utah, water with moderate salinity and high CO2 concentrations is leaking upwards into shallow aquifers that contain heavy-metal-bearing concretions. The aquifer system is comprised of the Navajo and Kayenta formations, which are pervasive across southern Utah and have been considered as a potential GCS injection unit where they are sufficiently deep. Numerical models of the site were constructed based on measured water chemistry and head distributions from previous studies. Simulations were used to improve understanding of the rate and distribution of the upwelling flow into the aquifers, and to assess the reactive transport processes that may occur if the upwelling fluids were to interact with a zone of iron oxide and other heavy metals, representing the concretions that are common in the area. Various mineralogies were tested, including one in which Pb2+ was adsorbed onto ferrihydrite, and another in which it was bound within a solid mixture of litharge (PbO) and hematite (Fe2O3). Results indicate that metal mobilization depends strongly on the source-zone composition and that Pb2+ transport can be naturally attenuated by gas-phase formation and carbonate-mineral precipitation. These findings could be used to improve risk assessment and mitigation strategies at geological carbon sequestration sites. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":"117 7","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41281608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Q. Fisher, F. Schaefer, I. Kaminskaite, D. Dewhurst, G. Yielding
Predicting the sealing capacity of faults and caprocks has been a long-standing uncertainty for those involved in the exploration, appraisal and development of petroleum reservoirs. In more recent years, interest in the topic has increased in a wide range of other applications, particularly those related to the decarbonization of our energy supply such as carbon capture and storage (CCS), radioactive waste disposal, geothermal energy production and underground energy storage (e.g. compressed air, hydrogen). Knowledge of how faults impact fluid flow is also important for management of drinking water supplies. To communicate new advances in research in these areas, the EAGE organized the first international conference on Fault and Top Seals in 2003. These conferences have continued to be held at roughly 4 yearly intervals and have brought together scientists from a wide range of disciplines to discuss new research findings and workflows relevant to predicting fault and top seal behaviour, as well as presenting case studies covering both successful and unsuccessful attempts to predict sealing capacity. Thematic collection: This article is part of the Fault and top seals collection available at: https://www.lyellcollection.org/cc/fault-and-top-seals-2019
{"title":"Fault and top seals thematic collection: a perspective","authors":"Q. Fisher, F. Schaefer, I. Kaminskaite, D. Dewhurst, G. Yielding","doi":"10.1144/petgeo2020-136","DOIUrl":"https://doi.org/10.1144/petgeo2020-136","url":null,"abstract":"Predicting the sealing capacity of faults and caprocks has been a long-standing uncertainty for those involved in the exploration, appraisal and development of petroleum reservoirs. In more recent years, interest in the topic has increased in a wide range of other applications, particularly those related to the decarbonization of our energy supply such as carbon capture and storage (CCS), radioactive waste disposal, geothermal energy production and underground energy storage (e.g. compressed air, hydrogen). Knowledge of how faults impact fluid flow is also important for management of drinking water supplies. To communicate new advances in research in these areas, the EAGE organized the first international conference on Fault and Top Seals in 2003. These conferences have continued to be held at roughly 4 yearly intervals and have brought together scientists from a wide range of disciplines to discuss new research findings and workflows relevant to predicting fault and top seal behaviour, as well as presenting case studies covering both successful and unsuccessful attempts to predict sealing capacity. Thematic collection: This article is part of the Fault and top seals collection available at: https://www.lyellcollection.org/cc/fault-and-top-seals-2019","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48371825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to reduce uncertainties around CO2 containment for the South West Hub CCS site (Western Australia), conceptual fault hydrodynamic models were defined and numerical simulations were carried out. These simulations model worst-case scenarios with a plume reaching a main compartment-bounding fault near the proposed injection depth and at the faulted interface between the primary and secondary containment interval. The conceptual models incorporate host-rock and fault properties accounting for fault-zone lithology, cementation and cataclastic processes but with no account made for geomechanical processes as the risk of reactivation is perceived as low. Flow simulations were performed to assess cross-fault and upfault migration in the case of plume–faults interaction. Results near the injection depth suggest that the main faults are likely to experience a significant reduction in transmissivity and impede CO2 flow. This could promote the migration of CO2 vertically or along the stratigraphic dip. Results near the interface between the primary and secondary containment intervals show that none of the main faults would critically control CO2 flow nor would they act as primary leakage pathways. CO2 flow is predicted to be primarily controlled by the sedimentological morphology. The presence of baffles in the secondary containment interval is expected to be associated with local CO2 accumulations; additional permeability impacts introduced by faults are minor. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage
{"title":"Flow modelling to quantify structural control on CO2 migration and containment, CCS South West Hub, Australia","authors":"L. Langhi, J. Strand, L. Ricard","doi":"10.1144/petgeo2020-094","DOIUrl":"https://doi.org/10.1144/petgeo2020-094","url":null,"abstract":"In order to reduce uncertainties around CO2 containment for the South West Hub CCS site (Western Australia), conceptual fault hydrodynamic models were defined and numerical simulations were carried out. These simulations model worst-case scenarios with a plume reaching a main compartment-bounding fault near the proposed injection depth and at the faulted interface between the primary and secondary containment interval. The conceptual models incorporate host-rock and fault properties accounting for fault-zone lithology, cementation and cataclastic processes but with no account made for geomechanical processes as the risk of reactivation is perceived as low. Flow simulations were performed to assess cross-fault and upfault migration in the case of plume–faults interaction. Results near the injection depth suggest that the main faults are likely to experience a significant reduction in transmissivity and impede CO2 flow. This could promote the migration of CO2 vertically or along the stratigraphic dip. Results near the interface between the primary and secondary containment intervals show that none of the main faults would critically control CO2 flow nor would they act as primary leakage pathways. CO2 flow is predicted to be primarily controlled by the sedimentological morphology. The presence of baffles in the secondary containment interval is expected to be associated with local CO2 accumulations; additional permeability impacts introduced by faults are minor. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48663676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Steventon, C. Jackson, H. Johnson, D. Hodgson, Sean Kelly, J. Omma, Christine Gopon, C. Stevenson, P. Fitch
The geometry, distribution and rock properties (i.e. porosity and permeability) of turbidite reservoirs, and the processes associated with turbidity current deposition, are relatively well known. However, less attention has been given to the equivalent properties resulting from laminar sediment gravity-flow deposition, with most research limited to cogenetic turbidite debrites (i.e. transitional-flow deposits) or subsurface studies that focus predominantly on seismic-scale mass-transport deposits (MTDs). Thus, we have a limited understanding of the ability of subseismic MTDs to act as hydraulic seals, and their effect on hydrocarbon production and/or carbon storage. We investigate the gap between seismically resolvable and subseismic MTDs, and transitional-flow deposits on long-term reservoir performance in this analysis of a small (<10 km-radius submarine fan system), Late Jurassic, sandstone-rich stacked turbidite reservoir (Magnus Field, Northern North Sea). We use core, petrophysical logs, pore fluid pressure, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and 3D seismic-reflection datasets to quantify the type and distribution of sedimentary facies and rock properties. Our analysis is supported by a relatively long (c. 37 years) and well-documented production history. We recognize a range of sediment gravity deposits: (i) thick-/thin-bedded, structureless and structured turbidite sandstone, constituting the primary productive reservoir facies (c. porosity = 22%, permeability = 500 mD); (ii) a range of transitional-flow deposits; and (iii) heterogeneous mud-rich sandstones interpreted as debrites (c. porosity ≤ 10%, volume of clay = 35%, up to 18 m thick). Results from this study show that over the production timescale of the Magnus Field, debrites act as barriers, compartmentalizing the reservoir into two parts (upper and lower reservoir), and transitional-flow deposits act as baffles, impacting sweep efficiency during production. Prediction of the rock properties of laminar- and transitional-flow deposits, and their effect on reservoir distribution, has important implications for: (i) exploration play concepts, particularly in predicting the seal potential of MTDs; (ii) pore-pressure prediction within turbidite reservoirs; and (iii) the impact of transitional-flow deposits on reservoir quality and sweep efficiency. Supplementary material: of data and methods are available at https://doi.org/10.6084/m9.figshare.c.5313860
{"title":"Evolution of a sand-rich submarine channel–lobe system, and the impact of mass-transport and transitional-flow deposits on reservoir heterogeneity: Magnus Field, Northern North Sea","authors":"M. Steventon, C. Jackson, H. Johnson, D. Hodgson, Sean Kelly, J. Omma, Christine Gopon, C. Stevenson, P. Fitch","doi":"10.1144/petgeo2020-095","DOIUrl":"https://doi.org/10.1144/petgeo2020-095","url":null,"abstract":"The geometry, distribution and rock properties (i.e. porosity and permeability) of turbidite reservoirs, and the processes associated with turbidity current deposition, are relatively well known. However, less attention has been given to the equivalent properties resulting from laminar sediment gravity-flow deposition, with most research limited to cogenetic turbidite debrites (i.e. transitional-flow deposits) or subsurface studies that focus predominantly on seismic-scale mass-transport deposits (MTDs). Thus, we have a limited understanding of the ability of subseismic MTDs to act as hydraulic seals, and their effect on hydrocarbon production and/or carbon storage. We investigate the gap between seismically resolvable and subseismic MTDs, and transitional-flow deposits on long-term reservoir performance in this analysis of a small (<10 km-radius submarine fan system), Late Jurassic, sandstone-rich stacked turbidite reservoir (Magnus Field, Northern North Sea). We use core, petrophysical logs, pore fluid pressure, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and 3D seismic-reflection datasets to quantify the type and distribution of sedimentary facies and rock properties. Our analysis is supported by a relatively long (c. 37 years) and well-documented production history. We recognize a range of sediment gravity deposits: (i) thick-/thin-bedded, structureless and structured turbidite sandstone, constituting the primary productive reservoir facies (c. porosity = 22%, permeability = 500 mD); (ii) a range of transitional-flow deposits; and (iii) heterogeneous mud-rich sandstones interpreted as debrites (c. porosity ≤ 10%, volume of clay = 35%, up to 18 m thick). Results from this study show that over the production timescale of the Magnus Field, debrites act as barriers, compartmentalizing the reservoir into two parts (upper and lower reservoir), and transitional-flow deposits act as baffles, impacting sweep efficiency during production. Prediction of the rock properties of laminar- and transitional-flow deposits, and their effect on reservoir distribution, has important implications for: (i) exploration play concepts, particularly in predicting the seal potential of MTDs; (ii) pore-pressure prediction within turbidite reservoirs; and (iii) the impact of transitional-flow deposits on reservoir quality and sweep efficiency. Supplementary material: of data and methods are available at https://doi.org/10.6084/m9.figshare.c.5313860","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43204220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Maleki, S. Danaei, Felipe Bruno Mesquita da Silva, A. Davolio, D. Schiozer
Recently, time-lapse seismic (4D seismic) has been steadily used to demonstrate the relation between field depletion and 4D seismic response, and, subsequently, to provide more efficient field management. A key component of reservoir monitoring is the knowledge of fluid movement and pressure variation. This information is vital in assisting infill drilling and as a reliable source of data to update reservoir models, and, consequently, in helping to improve model-based reservoir management and decision-making processes. However, in practice, varying levels of uncertainty are inherent in the 4D seismic interpretation of reservoirs that uses a multipart production regime. The complex nature of some 4D seismic signals emphasizes the role of the competing effects of geology, rock and fluid interactions. Hence, a reliable 4D interpretation requires an interdisciplinary approach that entails data analysis and insights from geophysics, engineering and geology. In this study, a stepwise workflow was introduced to reduce the uncertainties in the 4D seismic interpretation and to identify the improvements required in order to perform better reservoir surveillance. In parallel, the workflow demonstrates the use of engineering data analysis in conducting a consistent interpretation, and encompasses the 3D and 4D seismic attributes with engineering data analysis. This study was carried out in a Brazilian heavy-oil offshore field where production started in 2013. The field experienced intense production activity up to 2016, making the deep-water field an ideal candidate to explore the challenges in interpreting complex 4D signals. Beyond these challenges, a significant understanding of reservoir behaviour is obtained and improvements to the reservoir simulation model are suggested that could assist reservoir engineers with data assimilation applications.
{"title":"Stepwise uncertainty reduction in time-lapse seismic interpretation using multi-attribute analysis","authors":"M. Maleki, S. Danaei, Felipe Bruno Mesquita da Silva, A. Davolio, D. Schiozer","doi":"10.1144/petgeo2020-087","DOIUrl":"https://doi.org/10.1144/petgeo2020-087","url":null,"abstract":"Recently, time-lapse seismic (4D seismic) has been steadily used to demonstrate the relation between field depletion and 4D seismic response, and, subsequently, to provide more efficient field management. A key component of reservoir monitoring is the knowledge of fluid movement and pressure variation. This information is vital in assisting infill drilling and as a reliable source of data to update reservoir models, and, consequently, in helping to improve model-based reservoir management and decision-making processes. However, in practice, varying levels of uncertainty are inherent in the 4D seismic interpretation of reservoirs that uses a multipart production regime. The complex nature of some 4D seismic signals emphasizes the role of the competing effects of geology, rock and fluid interactions. Hence, a reliable 4D interpretation requires an interdisciplinary approach that entails data analysis and insights from geophysics, engineering and geology. In this study, a stepwise workflow was introduced to reduce the uncertainties in the 4D seismic interpretation and to identify the improvements required in order to perform better reservoir surveillance. In parallel, the workflow demonstrates the use of engineering data analysis in conducting a consistent interpretation, and encompasses the 3D and 4D seismic attributes with engineering data analysis. This study was carried out in a Brazilian heavy-oil offshore field where production started in 2013. The field experienced intense production activity up to 2016, making the deep-water field an ideal candidate to explore the challenges in interpreting complex 4D signals. Beyond these challenges, a significant understanding of reservoir behaviour is obtained and improvements to the reservoir simulation model are suggested that could assist reservoir engineers with data assimilation applications.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48401510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The construction of subsurface reservoir models is typically aided by the use of outcrops and modern analogue systems. We show how process-based models of depositional systems help to develop and substantiate reservoir architectural concepts. Process-based models can simulate assumptions relating to the physical processes influencing sedimentary deposition, accumulation and erosion on the resultant 3D sediment distribution. In this manner, a complete suite of analogue geometries can be produced by implementing different sets of boundary conditions based on hypotheses of depositional controls. Simulations are therefore not driven by a desired/defined outcome in the depositional patterns, but their application to date in reservoir modelling workflows has been limited because they cannot be conditioned to data such as well logs or seismic information. In this study a reservoir modelling methodology is presented that addresses this problem using a two-step approach: process-based models producing 3D sediment distributions that are subsequently used to generate training images for multi-point geostatistics. The approach has been tested on a dataset derived from a well-exposed outcrop from central Utah. The Ferron Sandstone Member includes a shallow-marine deltaic interval that has been digitally mapped using a high-resolution unmanned aerial vehicle (UAV) survey in 3D to produce a virtual outcrop (VO). The VO was used as the basis to build a semi-deterministic outcrop reference model (ORM) against which to compare the results of the combined process/multiple-point statistics (MPS) geostatistical realizations. Models were compared statically and dynamically through flow simulation. When used with a dense well dataset, the MPS realizations struggle to account for the high levels of non-stationarity inherent in the depositional system that are captured in the process-based training image. When trends are extracted from the outcrop analogue and used to condition the simulation, the geologically realistic geometries and spatial relationships from the process-based models are directly imparted onto the modelling domain, whilst simultaneously allowing the facies models to be conditioned to subsurface data. When sense-checked against preserved analogues, this approach reproduces more realistic architectures than traditional, more stochastic techniques.
{"title":"Combining process-based models and multiple-point geostatistics for improved reservoir modelling","authors":"J. Mullins, H. van der Vegt, J. Howell","doi":"10.1144/petgeo2020-012","DOIUrl":"https://doi.org/10.1144/petgeo2020-012","url":null,"abstract":"The construction of subsurface reservoir models is typically aided by the use of outcrops and modern analogue systems. We show how process-based models of depositional systems help to develop and substantiate reservoir architectural concepts. Process-based models can simulate assumptions relating to the physical processes influencing sedimentary deposition, accumulation and erosion on the resultant 3D sediment distribution. In this manner, a complete suite of analogue geometries can be produced by implementing different sets of boundary conditions based on hypotheses of depositional controls. Simulations are therefore not driven by a desired/defined outcome in the depositional patterns, but their application to date in reservoir modelling workflows has been limited because they cannot be conditioned to data such as well logs or seismic information. In this study a reservoir modelling methodology is presented that addresses this problem using a two-step approach: process-based models producing 3D sediment distributions that are subsequently used to generate training images for multi-point geostatistics. The approach has been tested on a dataset derived from a well-exposed outcrop from central Utah. The Ferron Sandstone Member includes a shallow-marine deltaic interval that has been digitally mapped using a high-resolution unmanned aerial vehicle (UAV) survey in 3D to produce a virtual outcrop (VO). The VO was used as the basis to build a semi-deterministic outcrop reference model (ORM) against which to compare the results of the combined process/multiple-point statistics (MPS) geostatistical realizations. Models were compared statically and dynamically through flow simulation. When used with a dense well dataset, the MPS realizations struggle to account for the high levels of non-stationarity inherent in the depositional system that are captured in the process-based training image. When trends are extracted from the outcrop analogue and used to condition the simulation, the geologically realistic geometries and spatial relationships from the process-based models are directly imparted onto the modelling domain, whilst simultaneously allowing the facies models to be conditioned to subsurface data. When sense-checked against preserved analogues, this approach reproduces more realistic architectures than traditional, more stochastic techniques.","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42687509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon capture, utilization and storage (CCUS) is considered a major part of the Portuguese strategy for reducing CO2 emissions. Some industrial sectors, the most prominent being the cement sector, require the implementation of CO2 storage to reach carbon neutrality by 2050. This paper presents and characterizes the areas with potential for CO2 storage in mainland Portugal. The lithostratigraphic and tectonic frameworks of the onshore and offshore basins are presented; a site screening process was conducted, based on basin- and regional-scale assessments, resulting in the definition of eight possible storage clusters, seven of which are offshore. The storage capacity was estimated for those clusters, with a central (P50) value of 7.09 Gt; however, the most interesting locations are in the Lusitanian Basin (West Iberian Margin), both onshore and offshore, as they present high capacity and are located favourably in relation to the industrial CO2 emitters. Considering only the potential sites of this basin, their storage capacities are greater than 3 Gt CO2, of which 260 Mt are onshore. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage
{"title":"Identification and characterization of geological formations with CO2 storage potential in Portugal","authors":"P. Pereira, C. Ribeiro, J. Carneiro","doi":"10.1144/petgeo2020-123","DOIUrl":"https://doi.org/10.1144/petgeo2020-123","url":null,"abstract":"Carbon capture, utilization and storage (CCUS) is considered a major part of the Portuguese strategy for reducing CO2 emissions. Some industrial sectors, the most prominent being the cement sector, require the implementation of CO2 storage to reach carbon neutrality by 2050. This paper presents and characterizes the areas with potential for CO2 storage in mainland Portugal. The lithostratigraphic and tectonic frameworks of the onshore and offshore basins are presented; a site screening process was conducted, based on basin- and regional-scale assessments, resulting in the definition of eight possible storage clusters, seven of which are offshore. The storage capacity was estimated for those clusters, with a central (P50) value of 7.09 Gt; however, the most interesting locations are in the Lusitanian Basin (West Iberian Margin), both onshore and offshore, as they present high capacity and are located favourably in relation to the industrial CO2 emitters. Considering only the potential sites of this basin, their storage capacities are greater than 3 Gt CO2, of which 260 Mt are onshore. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44962576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Max Casson, J. Jeremiah, G. Calvès, F. Goyet, K. Reuber, M. Bidgood, D. Reháková, L. Bulot, J. Redfern
Segmentation of the Guyanas continental margin of South America is inherited from the dual-phase Mesozoic rifting history controlling the first-order post-rift sedimentary architecture. The margin is divided into two segments by a transform marginal plateau (TMP), the Demerara Rise, into the Central and Equatorial Atlantic domains. This paper investigates the heterogeneities in the post-rift sedimentary systems at a mega-regional scale (>1000 km). Re-sampling seven key exploration wells and scientific boreholes provides new data (189 analysed samples) that have been used to build a high-resolution stratigraphic framework using multiple biostratigraphic techniques integrated with organic geochemistry to refine the timing of 10 key stratigraphic surfaces and three megasequences. The results have been used to calibrate the interpretation of a margin-scale two-dimensional seismic reflection dataset, and to build megasequence isochore maps, structural restorations and gross depositional environment maps at key time intervals of the margin evolution. Our findings revise the dating of the basal succession drilled by the A2-1 well, indicating that the oldest post-rift sequence penetrated along the margin is late Tithonian age (previously Callovian). Early Central Atlantic carbonate platform sediments passively infilled subcircular-shaped basement topography controlled by the underlying basement structure of thinned continental crust. Barremian–Aptian rifting in the Equatorial Atlantic, caused folding and thrusting of the Demerara Rise, resulting in major uplift, gravitational margin collapse, transpressional structures and peneplanation of up to 1 km of sediment capped by the regional angular Base Albian Unconformity. Equatorial Atlantic rifting led to margin segmentation and the formation of the TMP, where two major unconformities developed during the intra Late Albian and base Cenomanian. These two unconformities are time synchronous with oceanic crust accretion offshore French Guiana and in the Demerara–Guinea transform, respectively. A marine connection between the Central and Equatorial Atlantic is demonstrated by middle Late Albian times, coinciding with deposition of the organic-rich source rock of the Canje Formation (average total organic carbon 4.21%). The succession is variably truncated by the Middle Campanian Unconformity. Refining the stratigraphic framework within the context of the structural evolution and segmentation of the Guyanas margin impacts the understanding of key petroleum system elements. Supplementary material: Photographs of sandstone petrography thin sections (Fig. S1); calcareous nannofossil plates (Fig. S2); palynology reports for A2-1 and FG2-1 (Fig. S3); taxonomy description of new species; sample table and organic geochemistry results (Table S1); and nannofossil distribution charts (Table S2) are available at https://doi.org/10.6084/m9.figshare.c.5280490
{"title":"Evaluating the segmented post-rift stratigraphic architecture of the Guyanas continental margin","authors":"Max Casson, J. Jeremiah, G. Calvès, F. Goyet, K. Reuber, M. Bidgood, D. Reháková, L. Bulot, J. Redfern","doi":"10.1144/petgeo2020-099","DOIUrl":"https://doi.org/10.1144/petgeo2020-099","url":null,"abstract":"Segmentation of the Guyanas continental margin of South America is inherited from the dual-phase Mesozoic rifting history controlling the first-order post-rift sedimentary architecture. The margin is divided into two segments by a transform marginal plateau (TMP), the Demerara Rise, into the Central and Equatorial Atlantic domains. This paper investigates the heterogeneities in the post-rift sedimentary systems at a mega-regional scale (>1000 km). Re-sampling seven key exploration wells and scientific boreholes provides new data (189 analysed samples) that have been used to build a high-resolution stratigraphic framework using multiple biostratigraphic techniques integrated with organic geochemistry to refine the timing of 10 key stratigraphic surfaces and three megasequences. The results have been used to calibrate the interpretation of a margin-scale two-dimensional seismic reflection dataset, and to build megasequence isochore maps, structural restorations and gross depositional environment maps at key time intervals of the margin evolution. Our findings revise the dating of the basal succession drilled by the A2-1 well, indicating that the oldest post-rift sequence penetrated along the margin is late Tithonian age (previously Callovian). Early Central Atlantic carbonate platform sediments passively infilled subcircular-shaped basement topography controlled by the underlying basement structure of thinned continental crust. Barremian–Aptian rifting in the Equatorial Atlantic, caused folding and thrusting of the Demerara Rise, resulting in major uplift, gravitational margin collapse, transpressional structures and peneplanation of up to 1 km of sediment capped by the regional angular Base Albian Unconformity. Equatorial Atlantic rifting led to margin segmentation and the formation of the TMP, where two major unconformities developed during the intra Late Albian and base Cenomanian. These two unconformities are time synchronous with oceanic crust accretion offshore French Guiana and in the Demerara–Guinea transform, respectively. A marine connection between the Central and Equatorial Atlantic is demonstrated by middle Late Albian times, coinciding with deposition of the organic-rich source rock of the Canje Formation (average total organic carbon 4.21%). The succession is variably truncated by the Middle Campanian Unconformity. Refining the stratigraphic framework within the context of the structural evolution and segmentation of the Guyanas margin impacts the understanding of key petroleum system elements. Supplementary material: Photographs of sandstone petrography thin sections (Fig. S1); calcareous nannofossil plates (Fig. S2); palynology reports for A2-1 and FG2-1 (Fig. S3); taxonomy description of new species; sample table and organic geochemistry results (Table S1); and nannofossil distribution charts (Table S2) are available at https://doi.org/10.6084/m9.figshare.c.5280490","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49619639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Long-Chuan Wu, R. Thorsen, S. Ottesen, R. Meneguolo, K. Hartvedt, P. Ringrose, B. Nazarian
An understanding of fault seal is crucial for assessing the storage capacity and containment risks of CO2 storage sites, as it can significantly affect the projects on across-fault and along-fault migration/leakage risk, as well as reservoir pressure predictions. We present a study from the Smeaheia area in the northern Horda Platform offshore Norway, focusing on two fault-bounded structural closures, namely the Alpha and Beta structures. We aim to use this study to improve the geological understanding of the northern Horda Platform for CO2 storage scale-up potentials and illustrate the importance of fault seal analysis in containment risk assessment and storage capacity evaluation of a CO2 storage project. Our containment risk assessment shows that the Alpha structure has low fault-related containment risks; thus, it has a potential value to be an additional storage target. The Beta structure shows larger fault-related containment risks due to juxtaposition of the prospective storage aquifer with the basement across the Øygarden Fault System. The storage capacity of Smeaheia will be determined by the long-term dynamic interplay between pressure depletion and recharging. Our study shows that across-fault pressure communication between Smeaheia and the depleting Troll reservoir is likely to be through several relay ramps of the Vette Fault System. However, Smeaheia also shows pressure-recharging potentials, such as through the subcropping areas at the Base Nordland Unconformity. The depletion observed in the newly drilled well 32/4-3S gives a good validation point for our fault seal predictions and provides valuable insights for future dynamic simulations. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage
{"title":"Significance of fault seal in assessing CO2 storage capacity and containment risks – an example from the Horda Platform, northern North Sea","authors":"Long-Chuan Wu, R. Thorsen, S. Ottesen, R. Meneguolo, K. Hartvedt, P. Ringrose, B. Nazarian","doi":"10.1144/petgeo2020-102","DOIUrl":"https://doi.org/10.1144/petgeo2020-102","url":null,"abstract":"An understanding of fault seal is crucial for assessing the storage capacity and containment risks of CO2 storage sites, as it can significantly affect the projects on across-fault and along-fault migration/leakage risk, as well as reservoir pressure predictions. We present a study from the Smeaheia area in the northern Horda Platform offshore Norway, focusing on two fault-bounded structural closures, namely the Alpha and Beta structures. We aim to use this study to improve the geological understanding of the northern Horda Platform for CO2 storage scale-up potentials and illustrate the importance of fault seal analysis in containment risk assessment and storage capacity evaluation of a CO2 storage project. Our containment risk assessment shows that the Alpha structure has low fault-related containment risks; thus, it has a potential value to be an additional storage target. The Beta structure shows larger fault-related containment risks due to juxtaposition of the prospective storage aquifer with the basement across the Øygarden Fault System. The storage capacity of Smeaheia will be determined by the long-term dynamic interplay between pressure depletion and recharging. Our study shows that across-fault pressure communication between Smeaheia and the depleting Troll reservoir is likely to be through several relay ramps of the Vette Fault System. However, Smeaheia also shows pressure-recharging potentials, such as through the subcropping areas at the Base Nordland Unconformity. The depletion observed in the newly drilled well 32/4-3S gives a good validation point for our fault seal predictions and provides valuable insights for future dynamic simulations. Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage","PeriodicalId":49704,"journal":{"name":"Petroleum Geoscience","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2021-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48311959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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