Techno-economic evaluation of CO₂-EOR in the North Sea

CO2-EOR is a possible means to produce incremental oil from active oil fields. In the ongoing climate change debate, it is also welcomed as a business case for geological storage of CO2 (CO2 Capture and Storage, CCS). The possibility for applying this technology in the North Sea has been under discussion for several years, but the high cost and financial risk have hampered its deployment until today. Using the techno-economic simulator PSS IV, potential CO2-EOR projects can be evaluated in a realistic way, considering technological, policy-related, economic and geological uncertainties using Monte-Carlo calculations. For the current study, around 450 to 750 MC runs were performed (lower for the Cluster, and depending on the field and scenario), which is considered to produce results in sufficient detail for the current set-up. This number is mainly limited by computing performance. PSS IV includes a unique feature, in that it makes project evaluations considering incomplete information about the future. Next to its standard Monte-Carlo methodology, where stochastic parameter values are changed slightly every calculation, a second level of Monte-Carlo calculations and stochastic parameters are used for creating an outlook towards the future. This methodology is called “limited foresight”, which produces near- optimal investment decisions. This is considered more realistic compared to an optimisation model, where actions are taken based on a perfect forecast of the future. This methodology is combined with Real Options analysis, to include the value of having future project flexibility.CO2-EOR is a possible means to produce incremental oil from active oil fields. In the ongoing climate change debate, it is also welcomed as a business case for geological storage of CO2 (CO2 Capture and Storage, CCS). The possibility for applying this technology in the North Sea has been under discussion for several years, but the high cost and financial risk have hampered its deployment until today. Using the techno-economic simulator PSS IV, potential CO2-EOR projects can be evaluated in a realistic way, considering technological, policy-related, economic and geological uncertainties using Monte-Carlo calculations. For the current study, around 450 to 750 MC runs were performed (lower for the Cluster, and depending on the field and scenario), which is considered to produce results in sufficient detail for the current set-up. This number is mainly limited by computing performance. PSS IV includes a unique feature, in that it makes project evaluations considering incomplete information about the future. Next to its standard Monte-Carlo methodology, where stochastic parameter values are changed slightly every calculation, a second level of Monte-Carlo calculations and stochastic parameters are used for creating an outlook towards the future. This methodology is called “limited foresight”, which produces near- optimal investment decisions. This is considered more realistic compared to an optimisation model, where actions are taken based on a perfect forecast of the future. This methodology is combined with Real Options analysis, to include the value of having future project flexibility

Spring Water Geochemistry: A Geothermal Exploration Tool in the Rhenohercynian Fold-and-Thrust Belt in Belgium

peer reviewedSpring water geochemistry is applied here to evaluate the geothermal potential in Rhenohercynian fold and thrust belt around the deepest borehole in Belgium (Havelange borehole: 5648 m MD). Fifty springs and (few) wells around Havelange borehole were chosen according to a multicriteria approach including the hydrothermal source of “Chaudfontaine” (T ≈ 36 ◦C) taken as a reference for the area. The waters sampled, except Chaudfontaine present an in-situ T range of 3.66–14.04 ◦C (mean 9.83 ◦C) and a TDS (dry residue) salinity range of 46–498 mg/L. The processing methods applied to the results are: hierarchical clustering, Piper and Stiff diagrams, TIS, heat map, boxplots, and geothermometry. Seven clusters are found and allow us to define three main water types. The first type, locally called “pouhon”, is rich in Fe and Mn. The second type contains an interesting concentration of the geothermal indicators: Li, Sr, Rb. Chaudfontaine and Moressée (≈5 km East from the borehole) belong to this group. This last locality is identified as a geothermal target for further investigations. The third group represents superficial waters with frequently high NO3 concentration. The application of conventional geothermometers in this context indicates very different reservoir temperatures. The field of applications of these geothermometers need to be review in these geological conditions.MEE

Economic threshold of CO2-EOR and CO2 storage in the North Sea: A case study of the Claymore, Scott and Buzzard oil fields

© 2018 Elsevier Ltd CO2-enhanced oil recovery in the North Sea can provide additional oil revenues, prolong the productive lifetime of oil fields, and potentially catalyse the large-scale deployment of CO2 geological storage. Under the current low oil prices, around and below 50 €/bbl, the investment is more difficult to justify. Here we show three case studies for the Claymore, Scott and Buzzard fields offshore of Scotland. A techno-economic assessment is made with the PSS IV simulator considering a low oil price scenario, market uncertainties and geological uncertainty. Stochastic parameters and project flexibility are used to simulate realistic project decisions. The Modified Internal Rate of Return (MIRR) is introduced as a performance indicator in combination with hurdle rate scenarios of 10, 11 and 12% for risk compensation. The possibility of continuing the storage of CO2 after oil production has stopped is considered, and reservoir uncertainty is introduced as stochastic parameters defining the EOR production profile. In terms of total value and development probability, the Buzzard field has the highest potential for a successful CO2-EOR project in all of the simulated scenarios, followed by Claymore and Scott. When compensating for field size, the Buzzard field still has the highest value per barrel of additionally produced oil, but the Scott field has a higher efficiency compared to Claymore. With an increase of the hurdle rate, the probability on investment in CO2-EOR decreases, but the probability on a profitable project increases. It also becomes more likely that if an EOR project is started, it will be followed by a CO2 storage phase. A hurdle rate of 12% even completely offsets the financial risk under the simulated conditions.status: publishe

Raffiner la lithostratigraphie, cyclostratigraphie et magnétostratigraphie dans des coupes Italiennes de référence d'âge Hauterivien (Bosso, Monte Acuto, Frontone) pour une comparaison future de résultats cyclostratigraphiques

Astrochronology has proven to be a powerful method to constrain the duration of geological periods. However in some geological periods, cyclostratigraphic studies give diverging results. For instance the duration of the Hauterivian Stage was estimated as 3.5 myr in central Italy, and 5.9 ± 0.4 myr in South-Eastern France and South-Eastern Spain (Martinez et al., 2015, Sprovieri et al., 2006). However the comparison of the cyclostratigraphic results of different sections requires to have an independent stratigraphic framework. For future comparison we are refining the lithostratigraphy, cyclostratigraphy and magnetostratigraphy of Italian sections by high resolution logging and sampling. This has already led to identify thin shale beds sequences that can be correlated between sections. These sequences can be useful for further study of the Maoilica Formation. Indeed such marker beds are the only stratigraphic markers that can be directly observed on the field. Their identification could therefore help to define the age of new sections.Assessment of the reproducibility of cyclostratigraphy during the Hauterivia

A study of ground movements in brussels (Belgium) monitored by persistent scatterer interferometry over a 25-year period

The time series of Synthetic Aperture Radar data acquired by four satellite missions (including ERS, Envisat, TerraSAR-X and Sentinel 1) were processed using Persistent Scatterer interferometric synthetic aperture radar (InSAR) techniques. The processed datasets provide a nearly continuous coverage from 1992 to 2017 over the Brussels Region (Belgium) and give evidence of ongoing, slow ground deformations. The results highlight an area of uplift located in the heart of the city, with a cumulative ground displacement of ±4 cm over a 25-year period. The rates of uplift appear to have decreased from 2 to 4 mm/year during the ERS acquisition period (1992-2006) down to 0.5-1 mm/year for the Sentinel 1 data (2014-2017). Uplift of the city centre is attributed to a reduction of groundwater extraction from the deeper (Cenozoic-Paleozoic) aquifers, related to the deindustrialization of the city centre since the 1970s. The groundwater levels attested by piezometers in these aquifers show a clear recharge trend which induced the uplift. Some areas of subsidence in the river valleys such as the Maelbeek can be related to the natural settlement of soft, young alluvial deposits, possibly increased by the load of buildings.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

High-resolution integrated stratigraphy of the Hauterivian in Umbria-Marche (Central Italy)

Lower Cretaceous Hauterivian sediments are found in Central Italy as part of the Maiolica Fm. These sediments present strongly contrasting lithologies. From the original radiolarian calcareous ooze that constituted the bulk of the initial deposits, biogenic silica exclusively migrated in cherts, while calcium carbonate reprecipitated into the limestones. Moreover, thin black shale levels and stylolites are enriched in insoluble elements and minerals, which contrast with the nearly pure limestone and chert (> 90 % CaCO3 and SiO2 respectively, mainly negative magnetic susceptibility for both). In this context, as part of the CRASH (Checking the Reproducibility of Astrochronology in the Hauterivian) project, we are testing whether a Milankovitch imprint is preserved through these lithologies, despite the diagenetic processes implied by their contrasting nature. High-resolution sampling was performed for cyclo- and magnetostratigraphic purposes in order to avoid the accumulation of positioning uncertainty coming from compiling heterogeneous data sets. To deal with the data in a comprehensive way we developed the StratigrapheR package, available in the free software environment R (https://CRAN.R-project.org/package=StratigrapheR). It is designed to generate lithologs and to process stratigraphical information for cyclostratigraphy. For the investigated sections it allowed to create high-resolution logs that can be queried in the R environment. As the high-resolution lithologs show all the features observed in the field they can be used to reduce the positioning uncertainties for future field missions as much as possible. Additionally they can be used to compare overlapping parts of different sections. Our preliminary work allows to correlate bundles of thin black shale sequences between two sections spanning overlapping deposition intervals, using magnetostratigraphy as a stratigraphic reference. This is further confirmed by organic matter (OM) analyses, showing similar OM preservation trends between the sections. On the other hand chert layers patterns are more difficult to match between sections. Similarities can be found using the black shale levels as reference, but discrepancies are equally frequent. The ubiquity and regularity of chert layering make it generally difficult to identify any specific pattern. Furthermore we document the "Weissert" and Faraoni events in our sections. Both present a decrease of the natural remanent magnetisation intensity, which would imply an effect of these events on magnetite. Magnetite is indeed the main contributor for the primary component of magnetisation in the Maiolica Fm. (Channell et al., 1995). The Faraoni level also marks a decrease in the concentration of lithogenic elements and in magnetic susceptibility. References Channell J. E. T., Cecca F. & Erba E. 1995. Correlations of Hauterivian and Barremian (Early Cretaceous) Stage Boundaries to Polarity Chrons. Earth Planet. Sci. Lett, 134, 125–40

Progressive increase in organic-matter burial and preservation from the “Weissert” event to the Faraoni event in Umbria-Marche (central Italy)

The Cretaceous experienced several Oceanic Anoxic Events (or OAEs). Anoxia in these events is indicated by deposits of black shales, enriched in organic matter (OM) compared to the layers below and above, strong carbon isotope perturbations, often with a negative excursion at the onset of the OAEs followed by a positive excursion, and concentration of redox-sensitive trace-elements (RSTE) (Baudin & Riquier 2014). Considered to be the earliest Cretaceous OAE (Baudin & Riquier, 2014), the Faraoni level is a short event first defined in the late Hauterivian sections of the Umbria-Marche Apennines (Cecca et al. 1994). It presents black shales enriched in OM with high concentrations of RSTE but lacks an important positive δ13C excursion (Baudin & Riquier, 2014). This event follows the “Weissert” event, a ca. 2.3 million year carbon isotope perturbation event taking place during the late Valanginian-early Hauterivian (Sprovieri et al. 2006). This latter event is not considered to be an OAE, as anoxia indicators such as RSTE high concentrations or OM-rich layers are not observed at least in the western Tethys (Westermann et al. 2010). In order to link those two seemingly opposite events, sections of Late Valanginian to Early Barremian age were studied in the Umbria-Marche Apennines, Italy. Lesser magnitude black shales preceding the Faraoni level were identified. They were correlated in two sections using magnetostratigraphy (Fig. 1). Rock-Eval and palynofacies analyses reveal that they are part of a longer-term trend of increased organic matter preservation and burial. In the black shales this is hinted by a progressive increase of total organic carbon (TOC) content, of the hydrogen index (HI), and by increasingly better preserved amorphous organic matter (AOM) towards the Faraoni level (Fig.1). This increase starts in the upper part of the M5n magnetochron. This is coeval with an increase in mercury concentration interpreted to be due to volcanic activity that was measured among others in the Bosso section (Charbonnier et al., 2018). Palaeoenvironmental differences between the Bosso and Frontone sections are shown by differences in palynomorphs and in organic matter preservation, and by the presence of slumps found in Frontone only

CO₂ storage and Enhanced Oil Recovery in the North Sea: Securing a low-carbon future for the UK

This report shows that accelerating deployment of CCS can enable CO2- EOR in the UKCS. Part of the CO2 that would otherwise need to go directly to dedicated storage in CCS projects can be used to drive CO2-EOR. That gives significant benefits to the wider UK economy - extending the producing life of the North Sea, reducing imports of oil, maintaining employment, developing new capability to drive exports, and additional direct and indirect taxation revenues. At a national level this synergy between CCS and CO2-EOR could provide the overall most cost effective way to accelerate this energy transition between 2018 and 2030, to meet Committee on Climate Change de- carbonisation pathways. This CO2-EOR route also achieves two desirable UK objectives. A business demand is created, which drives sequential construction of CO2 capture, which develops learning and reduces costs of CO2 supply, which enables cheaper low-carbon electricity. CCS by this route, with secure CO2 storage already proven, develops more rapidly to protect the onshore UK economy and industry from increasing carbon prices.This report shows that accelerating deployment of CCS can enable CO2- EOR in the UKCS. Part of the CO2 that would otherwise need to go directly to dedicated storage in CCS projects can be used to drive CO2-EOR. That gives significant benefits to the wider UK economy - extending the producing life of the North Sea, reducing imports of oil, maintaining employment, developing new capability to drive exports, and additional direct and indirect taxation revenues. At a national level this synergy between CCS and CO2-EOR could provide the overall most cost effective way to accelerate this energy transition between 2018 and 2030, to meet Committee on Climate Change de- carbonisation pathways. This CO2-EOR route also achieves two desirable UK objectives. A business demand is created, which drives sequential construction of CO2 capture, which develops learning and reduces costs of CO2 supply, which enables cheaper low-carbon electricity. CCS by this route, with secure CO2 storage already proven, develops more rapidly to protect the onshore UK economy and industry from increasing carbon prices