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Purpose: Concern about the environmental impact of agriculture caused by intensification is growing as large amounts of nutrients and contaminants are introduced into the environment. The aim of this paper is to identify the geogenic and agricultural controls on the elemental composition of European, grazing and agricultural soils. Materials and methods: Robust factor analysis was applied to data series for Al, B, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Se, Sr, U, Zn (ICP-MS) and SiO2, K2O, Na2O, Fe2O3, Al2O3 (XRF) based on the European GEMAS dataset. In addition, the following general soil properties were included: clay content, pH, chemical index of alteration (CIA), loss on ignition (LOI), cation exchange capacity (CEC), total organic carbon (TOC) and total carbon and total sulfur. Furthermore, this dataset was coupled to a dataset containing information of historic P2O5 fertilization across Europe. Also, a mass balance was carried out for Cd, Cu and Zn to determine if concentrations of these elements found in the soils have their origin in historic P2O5 fertilization. Results and discussion: Seven geogenic factors and one agricultural factor were found of which four prominent ones (all geogenic): chemical weathering, reactive iron-aluminum oxide minerals, clay minerals and carbonate minerals. Results for grazing and agricultural soils were near identical, which further proofs the prominence of geogenic controls on the elemental composition. When the cumulative amount of P2O5 fertilization was considered, no extra agriculture-related factors became visible. The mass balance confirms these observations. Conclusions: Overall, the geological controls are more important for the soil chemistry in agricultural and grazing land soils than the anthropogenic controls. © 2013 Springer-Verlag Berlin Heidelberg.

In the Netherlands the groundwater-surface water interaction processes vary spatially and temporarily. In this article we present maps of the spatial distribution of monthly water exchange modelled with the National Hydrological Instrument of the Netherlands (NHI) for three years that represent a dry, an average and a wet year. Additionally, for five characteristic regions we present the exchange in more detail, both the temporal variability and the origin of water fluxes. The simulation results provide a better understanding of the hydrogeological system. The Dutch water authorities use the maps in the planning process of measures to fulfil the framework directive of the European Union.

The presence of clay in fault zones has a dramatic effect on both fault mechanics and permeability. Quantification of this effect relies on small scale laboratory experiments or indirect observations from hydrocarbon fields, for which systematic variation of clay content, clay distribution, and deformation conditions can be problematic. Two-dimensional discrete element models of fault zones were deformed in simple shear to assess the effect of shale on failure criteria and sealing capacity using a systematic series of model simulations. Comparison between the evolution of shear stress and development of microcracks shows that changes in shear stress are correlated with alignment of microcracks, resulting in fractures with similar orientations as R- and Y-shears that can accommodate local deformation. Both shale content and distribution have a marked effect on the failure criteria of all fault models, i.e. with increasing volumetric shale content cohesion decreases up to a factor ~20 and friction coefficients drops below ~0.1 for some distributions. A tradeoff between permeability reduction due to the presence of low permeable clay and permeability increase due to local failure of fault rock determines the location of spill points and integrity of fault seals during gas storage

We propose a new workflow for building static reservoir models of siliciclastic fluvio-deltaic systems. The proposed strategy requires a process-based stratigraphic simulation model which incorporates a reservoir-scale alluvial architecture module nested within a low-resolution basin-scale (sequence-stratigraphic) model. The basin-scale model is run with the intent to approximate large-scale basin-fill properties (based on geological/geophysical background information about palaeotopography, sea level, sediment supply, subsidence, and so forth). Subsequently, the model may be stochastically optimised by dedicated post-processing software to mimic sub-grid (reservoir-scale) properties of selected parts of the basin fill. This approach allows us to narrow down the range of possible scenarios (realisations) from the outset, which results in more reliable uncertainty estimates associated with reservoir models. Pilot studies suggest that the improvement of geological credibility of stochastically simulated fluvial reservoir models may go hand-in-hand with a significant reduction of the computational effort of inverting basin-scale (process-based) stratigraphic forward models. The implementation of geological constraints on object-based models is expected to improve estimation of sand-body connectivity and dynamic reservoir behaviour, and will therefore contribute to reduction of the non-uniqueness in current static reservoir models. Furthermore, the uncertainty associated with each basin-scale parameter can be propagated all the way through to reserve estimation. The partitioning of the overall uncertainty into contributions at the basin and reservoir scales may be quantitatively assessed, and the information content of all available data may be quantified. Copyright 2013, Society of Petroleum Engineers.

In the past years, many applications of historymatching methods in general and ensemble Kalman filter in particular have been proposed, especially in order to estimate fields that provide uncertainty in the stochastic process defined by the dynamical system of hydrocarbon recovery. Such fields can be permeability fields or porosity fields, but can also fields defined by the rock type (facies fields). The estimation of the boundaries of the geologic facies with ensemble Kalman filter (EnKF) was made, in different papers, with the aid of Gaussian random fields, which were truncated using various schemes and introduced in a historymatching process. In this paper, we estimate, in the frame of the EnKF process, the locations of three facies types that occur into a reservoir domain, with the property that each two could have a contact. The geological simulation model is a form of the general truncated plurigaussian method. The difference with other approaches consists in how the truncation scheme is introduced and in the observation operator of the facies types at the well locations. The projection from the continuous space of the Gaussian fields into the discrete space of the facies fields is realized through in an intermediary space (space with probabilities). This space connects the observation operator of the facies types at the well locations with the geological simulation model. We will test the model using a 2D reservoir which is connected with the EnKF method as a data assimilation technique. We will use different geostatistical properties for the Gaussian fields and different levels of the uncertainty introduced in the model parameters and also in the construction of the Gaussian fields

Mapping the Middle to Upper Pleistocene Rhine-Meuse sequence in the southern North Sea based on new core and seismic data has allowed a detailed palaeoenvironmental re-assessment. An integrated seismo-lithostratigraphic and malacological biostratigraphic framework is correlated with the optically stimulated luminescence-dated Rhine-Meuse sequence onshore. The data point to a dynamic interplay of fluvial and marine systems in the southern part of the North Sea driven by longer-term (>100 ka) tectonic and epeirogenic processes and shorter-term (100 ka) uplift of the Wealden-Artois synclinorium and compaction-driven subsidence of Tertiary shales within the Voorne Trough. The dominant erosive sedimentary signatures within the Rhine-Meuse sequence resulted through shorter-term (

Leaching of nitrate from agricultural land to groundwater and the resulting nitrate pollution are a major environmental problem worldwide. Its impact is often mitigated in aquifers hosting sufficiently reactive reductants that can promote autotrophic denitrification. In the case of pyrite acting as reductant, however, denitrification is associated with the release of sulfate and often also with the mobilization of trace metals (e.g., arsenic). In this study, reactive transport modeling was used to reconstruct, quantify and analyze the dynamics of the dominant biogeochemical processes in a nitrate-polluted pyrite-containing aquifer and its evolution over the last 50 years in response to changing agricultural practices. Model simulations were constrained by measured concentration depth profiles. Measured 3H/3He profiles were used to support the calibration of flow and conservative transport processes, while the comparison of simulated and measured sulfur isotope signatures acted as additional calibration constraint for the reactive processes affecting sulfur cycling. The model illustrates that denitrification largely prevented an elevated discharge of nitrate to surface waters, while sulfate discharges were significantly increased, peaking around 15 years after the maximum nitrogen inputs. © 2013 American Chemical Society.

A 3D geological raster model has been constructed of the onshore of the Netherlands. The model displays geological units for the upper 500 m in 3D in an internally consistent way. The units are based on the lithostratigraphical classification of the Netherlands. This classification is used to interpret a selection of boreholes from the national subsurface database. Additional geological information regarding faults, the areal extent of each unit and conceptual genetic models have been combined in an automated workflow to interpolate the basal surfaces of each unit on 100 × 100 metre (x,y dimensions) raster cells. The combination of all interpolated basal surfaces results in a 3D Digital Geological Model (DGM) of the subsurface. A measure of uncertainty of each of these surfaces is also given. The automated workflow ensures an easily updatable subsurface model. The outputs are available for end users through www.dinoloket.nl.

The ECCO Tool [1, 2] has been developed in the “ECCO – European value chain for CO2” project [3]. ECCO was a collaborating project under the 7th framework programme for research of the EU. The ECCO Tool is a software program designed to evaluate quantitatively the post-tax economics of Carbon Capture and Storage (CCS) projects for each of the mutually dependent actors along the CCS value chain. The main objective of ECCO is to facilitate robust strategic decision-making regarding early and future deployment of CO2 value chains [4]. The tool is designed to have a level of detail that is appropriate for studying the economic feasibility of welldefined CCS projects to be executed by commercial companies, studying whether or not to invest in (part of) the value chain and, if so, under which contractual conditions. The tool integrates cost engineering, transport and well/reservoir physics, planning (including the impact of contracts and physics on the sizing and timing of capex and opex), and full post-tax economics (including macro- and micro-economics). The ECCO Tool is also aimed at giving insight to national and European policy makers on their possible role in “closing the chain”,i.e., how they may contribute, through subsidies, guarantees, regulation or otherwise, to achieve a satisfactory risk and/or reward for the actors involved in a chain. Finally, the tool can also be used by authorities to estimate the potential of CCS in realizing overall policy objectives (e.g. meeting ETS objectives, amount of government stimulation needed, jobs created, etc). The subsurface module consists of three storage options, depleted gas field (DGF), aquifer and storage by enhanced oil recovery (EOR). In order to have a realistic behavior of the subsurface operator, automatic decision algorithms are included in the subsurface module. In order to meet the contractual obligations of the storage operator, e.g. to store a volume of CO2 within a certain period, incremental investments may be needed. These incremental investments depend on physical and contractual state-variables that are calculated as output of the subsurface module. Decision algorithms for incremental investments can be formulated such that the actual decisions are triggered as a function of these state variables

Compound-specific stable isotope analysis (CSIA) has, in combination with model-assisted interpretation, proven to be a valuable approach to quantify the extent of organic contaminant degradation in groundwater systems. CSIA data may also provide insights into the origin and transformation of diffuse pollutants, such as pesticides and nitrate, at the catchment scale. While CSIA methods for pesticides have increasingly become available, they have not yet been deployed to interpret isotope data of pesticides in surface water. We applied a coupled subsurface-surface reactive transport model (HydroGeoSphere) at the hillslope scale to investigate the usefulness of CSIA in the assessment of pesticide degradation. We simulated the transport and transformation of a pesticide in a hypothetical but realistic two-dimensional hillslope transect. The steady-state model results illustrate a strong increase of isotope ratios at the hillslope outlet, which resulted from degradation and long travel times through the hillslope during average hydrological conditions. In contrast, following an extreme rainfall event that induced overland flow, the simulated isotope ratios dropped to the values of soil water in the pesticide application area. These results suggest that CSIA can help to identify rainfall-runoff events that entail significant pesticide transport to the stream via surface runoff. Simulations with daily rainfall and evapotranspiration data and one pesticide application per year resulted in small seasonal variations of concentrations and isotope ratios at the hillslope outlet, which fell within the uncertainty range of current CSIA methods. This implies a good reliability of in-stream isotope data in the absence of transport via surface runoff or other fast transport routes, since the time of measurement appears to be of minor importance for the assessment of pesticide degradation. The analysis of simulated isotope ratios also allowed quantification of the contribution of two different reaction pathways (aerobic and anaerobic) to overall degradation, which gave further insight into the transport routes in the modelled system. The simulations supported the use of the commonly applied Rayleigh equation for the interpretation of CSIA data, since this led to an underestimation of the real extent of degradation of less than 12% at the hillslope outlet. Overall, this study emphasizes the applicability and usefulness of CSIA in the assessment of diffuse river pollution, and represents a first step towards a theoretical framework for the interpretation of CSIA data in agricultural catchments.©Author(s) 2013.

The Geological Model Calibration - Learnings from Integration of Reservoir Geology and Field Performance: example from the Upper Carboniferous Reservoirs of the Southern North Sea. Copyright © (2012) by the European Association of Geoscientists & Engineers All rights reserved.

The study presented in this paper is to investigate the possibility of using spaceborne remote sensing data for groundwater head prediction. Remotely-sensed soil moisture time series of SWI (Soil Water Index) derived from ERS (European Remote Sensing) scatterometers are used to predict groundwater head dynamics in the Rhine-Meuse basin, where over four thousand observed groundwater head time series are available. Our study consists of three evolving research steps. First, the correlation between observed time series of groundwater head and SWI is investigated. Second, SWI time series are used as input to a transfer-function noise (TFN) model for temporal prediction (forecasts) of groundwater heads. Third, TFN models with spatially interpolated parameters are used with SWI time series for spatio-temporal prediction of groundwater heads. Here, HAND (Height Above Nearest Drainage) as derived from a digital elevation model is used as auxiliary information. Results show that the correlation between SWI and groundwater head time series is apparent, particularly in areas with shallow groundwater, and that correlation increases when a time-lag is taken into account. Temporal predictions with TFN models reproduce observed groundwater head time series well at locations with shallow groundwater, but results are poor for locations with deep groundwater. The spatio-temporal prediction method is not able to estimate the absolute value of groundwater heads. However, head variation in terms of timing and amplitude is predicted reasonably well, in particular in areas with shallow groundwater. This suggests that, once a groundwater model is suitably calibrated, remotely sensed soil moisture data could be used to improve groundwater prediction in an operational data-assimilation framework. © 2013 Elsevier Inc.

In the current work evaluation of CO2 release velocity profiles is determined using Particle Image Velocimetry (PIV). The formation of solid CO2 particles using the rapid expansion of nozzle flow is used as a seeder particle, making the method truly nonintrusive and negates the use of special seeder equipment. Preliminary tests have been conducted on low speed large CO2 particles. High-speed release PIV experiments have been conducted for a range of storage pressures between 60 and 150 bars using a 13 mm (1/2 inch) diameter nozzle. The current paper is reporting combined research with a second paper by Dam et al. . The current investigation is a small scale experiment prior to reported mid scale experiments reported in Ahmed et al.

The circum-Antarctic Southern Ocean is an important region for global marine food webs and carbon cycling because of sea-ice formation and its unique plankton ecosystem. However, the mechanisms underlying the installation of this distinct ecosystem and the geological timing of its development remain unknown. Here, we show, on the basis of fossil marine dinoflagellate cyst records, that a major restructuring of the Southern Ocean plankton ecosystem occurred abruptly and concomitant with the first major Antarctic glaciation in the earliest Oligocene (∼33.6 million years ago). This turnover marks a regime shift in zooplankton-phytoplankton interactions and community structure, which indicates the appearance of eutrophic and seasonally productive environments on the Antarctic margin. We conclude that earliest Oligocene cooling, ice-sheet expansion, and subsequent sea-ice formation were important drivers of biotic evolution in the Southern Ocean.

The Werkendam (WED) and Barendrecht-Ziedewij (BRTZ) gas fields are CO2- and CH4-bearing stratigraphic equivalents in the Netherlands. A comparison in petrographic characteristics and burial histories of the two fields is performed to investigate long-term mineral reactions induced by the presence of CO2. The mineral relations in BRTZ are used as a CO2-free reference for WED. However, the results show that the differences in paragenetic sequence between the two fields are partially due to different temperature evolutions and fluid influxes. The mineral relations that can be linked to the presence of CO2 in WED are the partial dissolution of anhydrite and feldspar and the precipitation of siderite, quartz and potentially minor dolomite. The amount of CO2 sequestered in siderite (and potentially dolomite) is small. PHREEQC geochemical modelling was able to simulate the observations of the mineral reactions induced by carbonized brine. Yet, a sensitivity study on the type of illite used in the model, and the inclusion of minor minerals showed that significantly different reactions can be induced when input parameters are slightly varied. Furthermore the presence and type of Fe-minerals determines if and how much siderite forms. This shows that careful selection of initial mineralogy is required as model input. In one model run mineral reactions were predicted which are known from petrographic studies not to occur under the applied conditions. Hence, besides careful mineral selection, an expert opinion on diagenetic processes is necessary to guide the model towards the proper mineral reactions.

Ensemble Optimization (EnOpt) is a rapidly emerging method for reservoir model based production optimization. EnOpt uses an ensemble of controls to approximate the gradient of the objective function with respect to the controls. Current implementations of EnOpt use a Gaussian ensemble with a constant standard deviation, i.e. a diagonal covariance matrix with entries that remain constant during the optimization process. The Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES) is a gradient-free optimization method, developed in the 'machine learning' community, which also uses an ensemble of controls but with a covariance matrix that is continually updated during the optimization process. It has shown to be an efficient method for several difficult small dimension optimization problems and has recently been applied in the petroleum industry for well location and production optimization. In this study we investigated the scope to improve the computational efficiency of EnOpt through the use of covariance adaptation (CMA-EnOpt). We optimized water flooding of a multi-layer sector model containing multiple sealing and non-sealing faults. The controls used were inflow control valve settings at predefined time intervals for injectors and producers with undiscounted net present value as the objective function. We compared EnOpt and CMA-EnOpt starting from identical covariance matrices. We achieved slightly higher (0.7%-1.8%) objective function values and modest speed-ups with CMA-EnOpt compared to EnOpt, depending on choice of user-defined parameters in both algorithms. However, the major benefit of CMA-EnOpt is its robustness with respect to the initial choice of the covariance matrix. A poor choice of the initial matrix can be detrimental to EnOpt, whereas the CMA-EnOpt performance is near-independent of the initial choice. Copyright 2013, Society of Petroleum Engineers.

Time-lapse seismic data provide information on the dynamics of multiphase reservoir fluid flow in places where no production data from wells are available. This information, in principle, could be used to estimate unknown reservoir properties. However, the amount, resolution, and character of the data have long posed significant challenges for quantitative use in assisted-history- matching workflows. Previous studies, therefore, have generally investigated methods for updating single models with reduced parameter-uncertainty space. Recent developments in ensemble- based history-matching methods have shown the feasibility of multimodel history and matching of production data while maintaining a full uncertainty description. Here, we introduce a robust and flexible reparameterization for interpreted fluid fronts or seismic attribute isolines that extends these developments to seismic history matching. The seismic data set is reparameterized, in terms of arrival times, at observed front positions, thereby significantly reducing the number of data while retaining essential information. A simple 1D example is used to introduce the concepts of the approach. A synthetic 3D example, with spatial complexity that is typical for many water floods, is examined in detail. History-matching cases based on both separate and combined use of production and seismic data are examined. It is shown that consistent multimodel history matches can be obtained without the need for reduction of the parameter space or for localization of the impact of observations. The quality of forecasts based on the history-matched models is evaluated by simulating both expected production and saturation changes throughout the field for a fixed operating strategy. It is shown that bias and uncertainty in the forecasts of production both at existing wells and in the flooded area are reduced considerably when both production and seismic data are incorporated. The proposed workflow, therefore, enables better decisions on field developments that require optimal placement of infill wells. Copyright © 2013 Society of Petroleum Engineers.

Carbon capture and sequestration (CCS) is expected to become a serious CO2-emission reduction technology in the Netherlands. The industry- and government-supported national research programme CATO-2 is tasked to investigate the opportunities and feasibility of CCS projects, both onshore and offshore in the Dutch territory. An example of such opportunities are the deep aquifers and (soon-to-be) depleted gas reservoirs in the mature West

The economic production from shale gas reservoir depends on the success of hydraulic stimulation, which is aimed at the creation of a permeable complex fracture network. This is achieved by the reactivation of a natural fracture network; however, the reactivation may be accompanied by unwanted seismicity. Coupled modelling is required to completely describe the physical processes involved. We developed a model using FLAC3D, by implementing in it gas-flow, dynamic permeability changes and the development of seismic events during fracture reactivation. The geomechanical and the flow behaviour of the fracture were implemented using effective continuum parameters. For the activation of a fracture zone, we used the ubiquitous joint model available in FLAC3D. Fracture deformations are the result of both reversible tensile and irreversible shear deformations. Models with different numbers of fracture sets, parallel or intersecting, were developed and simulated. With our approach we can simulate and visualize fracture reactivation, permeability enhancement and the location and size of induced seismic events.

ULTimateCO2 will assess the long-term CO2 storage behaviour in terms of efficiency and security. The project is dedicated to studying the main physical processes needed to develop a better, quantitative understanding of the longterm geological storage of CO2, namely: (i) reservoir trapping, (ii) sealing integrity of caprock, and (iii) well leakage. Close collaboration with the NER300 candidates and EEPR demonstration sites will underpin all investigation with relevant supply of data industrial context. ULTimateCO2 will define a set of recommendations that will enable both regulators and operators to demonstrate that site specific long-term site performance will lead to permanent and safe CO2 containment.

Analysis of siliceous microfossils of a 79 cm long peat sediment core from Highlands Hammock State Park, Florida, revealed distinct changes in the local hydrology during the past 2,500 years. The coring site is a seasonally inundated forest where water availability is directly influenced by precipitation. Diatoms, chrysophyte statospores, sponge remains and phytoliths were counted in 25 samples throughout the core. Based on the relative abundance of diatom species, the record was subdivided into four diatom assemblage zones, which mainly reflect the hydrological state of the study site. An age-depth relationship based on radiocarbon measurements of eight samples reveals a basal age of the core of approximately 2,500 cal. yrs. BP. Two significant changes of diatom assemblage composition were found that could be linked to both, natural and anthropogenic influences. At 700 cal. yrs. BP, the diatom record documents a shift from tychoplanktonic Aulacoseira species to epiphytic Eunotia species, indicating a shortening of the hydroperiod, i. e. the time period during which a wetland is covered by water. This transition was interpreted as being triggered by natural climate change. In the middle of the twentieth century a second major turnover took place, at that time however, as a result of human impact on the park hydrology through the construction of dams and canals close to the study site. © 2011 The Author(s).

In river basins, soils, groundwater, riparian zones and floodplains, streams, rivers, lakes and reservoirs act as successive filters in which the hydrology, ecology and biogeochemical processing are strongly coupled and together act to retain a significant fraction of the nutrients transported. This paper compares existing river ecology concepts with current approaches to describe river biogeochemistry, and assesses the value of these concepts and approaches for understanding the impacts of interacting global change disturbances on river biogeochemistry. Through merging perspectives, concepts, and modeling techniques, we propose integrated model approaches that encompass both aquatic and terrestrial components in heterogeneous landscapes. In this model framework, existing ecological and biogeochemical concepts are extended with a balanced approach for assessing nutrient and sediment delivery, on the one hand, and nutrient in-stream retention on the other hand. © Author(s) 2013. CC Attribution 3.0 License.

A geomechanical modeling study was conducted to investigate stability of major faults during past gas production and future underground gas storage operations in a depleted gas field in the Netherlands. The field experienced induced seismicity during gas production, which was most likely caused by the reactivation of an internal Central fault separating the two major reservoir blocks. A 3D field scale geomechanical finite element model of the gas field was developed with realistic representation of the structural geology and juxtaposition of various lithologies across the Central fault. The model was calibrated to match the subsidence data and the approximate location of the critically stressed, reactivated part of the fault in agreement with the seismological localization of the hypocenters of the past major seismic events. The model predicted a maximum shear slip of up to 2 cm associated with gas production. Additional, but a smaller, fault slip of up to 0.5 cm could be expected during the subsequent phase of cushion gas injection. During annual cycles of gas injection and production, the Central fault is not critically stressed and the predicted stress changes lie in the elastic region. Although the fault slip is unlikely, continuous monitoring of induced seismicity is essential.

The successful surface waves retrieval in solid-Earth seismology using long-time correlations and subsequent tomographic images of the crust have sparked interest in extraction of subsurface information from noise in the exploration seismology. Subsurface information in exploration seismology is usually derived from body-wave reflections > 1 Hz, which is challenging for utilization of ambient noise. We use 11 h of noise recorded in the Sirte basin, Libya. First, we study the characteristics of the noise. We show that the bulk of the noise is composed of surface waves at frequencies below 6 Hz. Some noise panels contain nearly vertically traveling events. We further characterize these events using a beamforming algorithm. From the beamforming, we conclude that these events represent body-wave arrivals with a fairly rich azimuthal distribution. Having body-wave arrivals in the noise is a prerequisite for body-wave reflections retrieval. We crosscorrelate and sum the recorded ambient-noise panels to retrieve common-source gathers, following two approaches - using all the noise and using only noise panels containing body-wave arrivals likely to contribute to the reflections retrieval. Comparing the retrieved gathers with active seismic data, we show that the two-way traveltimes at short offsets of several retrieved events coincide with those of reflections in the active data and thus correspond to apexes of reflections. We then compare retrieved stacked sections of the subsurface from both approaches with the active-data stacked section and show that the reflectors are consistent along a line. The results from the second approach exhibit the reflectors better. © 2013. American Geophysical Union. All Rights Reserved.

Soil nitrogen (N) budgets are used in a global, distributed flow-path model with 0.5° &times 0.5° resolution, representing denitrification and N2O emissions from soils, groundwater and riparian zones for the period 1900-2000 and scenarios for the period 2000-2050 based on the Millennium Ecosystem Assessment. Total agricultural and natural N inputs from N fertilizers, animal manure, biological N2 fixation and atmospheric N deposition increased from 155 to 345 Tg N yr-1 (Tg 1/4 teragram; 1 Tg 1/4 1012 g) between 1900 and 2000. Depending on the scenario, inputs are estimated to further increase to 408-510 Tg N yr21 by 2050. In the period 1900-2000, the soil N budget surplus (inputs minus withdrawal by plants) increased from 118 to 202 Tg yr-1, and this may remain stable or further increase to 275 Tg yr-1 by 2050, depending on the scenario. N2 production from denitrification increased from 52 to 96 Tg yr21 between 1900 and 2000, and N2O-N emissions from 10 to 12 Tg N yr-1. The scenarios foresee a further increase to 142 Tg N2-N and 16 Tg N2O-N yr-1 by 2050. Our results indicate that riparian buffer zones are an important source of N2O contributing an estimated 0.9 Tg N2O-N yr-1 in 2000. Soils are key sites for denitrification and are much more important than groundwater and riparian zones in controlling the N flow to rivers and the oceans. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

This guide provides a major revision and update of the lithostratigraphy of the Rogaland Group for the Norwegian North Sea. An abundance of recent well and seismic data sheds new light on lithology, biostratigraphy, provenance, geographic distribution and terminology of all Rogaland rock units, used widely in the search for oil and gas. While finer siliciclastic units largely remain as previously defined, previous sandstone/siltstone formations and one (reworked) chalky unit are now re-defined. These lithostratigraphic units are local sediment bodies of a lithology different from the surrounding and embracing formation. Hence, these lithostratigraphic units are members in the formal stratigraphical hierarchy. With the new definitions and re-definitions the Rogaland Group now consists of four formations and 15 members, which span the stratigraphic interval from lower Paleocene to lower Eocene. The revisions concerning the sandstone bodies are of four different types: – Re-definition from formations to members – Re-definition of lithological criteria – Introduction of members long used already offshore England and Denmark – Definition of new members For those practicing geologists not familiar with historic precedence, an important ʻsine qua nonʼ in (litho-) stratigraphy, it should be pointed out that 8 out of 15 members discussed here have been predefined in literature dealing with the UK and Danish sectors of the North Sea. The present study thus updates the Norwegian lithostratigraphic bulletins of the nineteen eighties for its offshore area. The internet site www.nhm2.uio.no/ norlex provides an interactive digital version of this study, with links to well data, biozonations and core archives relevant to the Rogaland Group.

Shallow gas accumulations in the Plio-Pleistocene Eridanos Delta deposits in the Dutch offshore are a valuable additional hydrocarbon source. Ongoing studies focus on better understanding the shallow gas play. The focus of this paper is on increasing the understanding of the origin of the shallow gas. For that purpose we used integrated modeling approaches to assess the timing and spatial distribution of biogenic gas generation. It was found that intra-Eridanos Delta deposits are the most probable source of biogenic gas and that these biogenic sources are at maximum depth and temperature today. Detailed glacial-interglacial temperature fluctuations do not have a large influence on the history of the optimum window for biogenic gas generation, i.e. on start of biogenic gas generation. In the oldest and deepest buried units of the Delta, biogenic gas generation started already at the beginning of the Pleistocene, while the youngest units have not yet reached the optimum window for biogenic gas generation. Copyright © (2012) by the European Association of Geoscientists & Engineers All rights reserved.

The success of shale gas exploration and production in the United States has triggered other countries around the world to look into possibilities of producing gas from different shales. As it turns out, one of the main difficulties when looking for shale gas is obtaining an in depth understanding of the shale formations and interpret where the sweet spots for gas production will be. This is mainly caused by the large differences in properties of shale formations. To improve our understanding of the vertical and lateral property changes that determine high and low productivity zones in shales, TNO has proposed a workflow including well log interpretation, mud log interpretation, depth modeling, organic geochemistry, basin modeling, palynology, electron microscope analyses, mineral typing and porosity identification and characterization. This method serves as a solid basis for sweet spot determination and proper resource estimates. The proposed method has been applied to the two main possible shale gas reservoirs in the Netherlands; the Lower Jurassic Posidonia Shale Formation (PSF) and the Carboniferous (Namurian) Epen Formation. The latter is of particular interest as it contains the highly organic basal Geverik Member (GM). For the two formations detailed and accurate depth maps have been produced. Research on the PSF shows that a number of areas are expected to have reached gas maturity, together around a fifth of the total area of the formation. Besides shale gas there appears to be potential for shale oil. High productivity zones within these shales are expected in the deepest part of formation and orientated along the distribution axis within the West Netherlands Basin. In the multidisciplinary workflow a 3D faciesmodel of the formation is created using palynology and organofacies to detect prospective layers within the formation. This faciesmodel is then used in combination with log-interpretaion, seismic interpretation and sedimentological interpretation to detect most prospective zones and areas. FIB-SEM microscopy shows that coccoliths present in the formation can have large favourable effects on the porosity and permeability providing for a micropermeability pathway for oil and gas when interconnected. When the proposed workflow is applied to the Geverik Member, a correlation between silica content and Total Organic Carbon (TOC) is found, i.e. log-derived TOC is in general close to 10% when the dominant mineral type is silica. Geomechanical analysis of rock properties shows that the lower zone of the Geverik Member is the favourable layer to target, i.e. the layer is dominantly build up of quartz and silica suggesting preferential conditions for hydraulic stimulation.

During the last millennium, human intervention has had an increasing impact on the bathymetry of the Wadden Sea. The significance of these human-induced changes for the decadal-scale development of the Wadden Sea in light of natural sediment dynamics is still unknown. We compared a series of 20 th-century bathymetric grids and the top of the Pleistocene to calculate the decadal- to millennium-scale net sediment dynamics within the study area. Mean annual net sediment dynamics as determined from these comparisons is dependent on the time period considered. It is as high as 53 million m3 for 1999-2006, the shortest period considered, but less than 3 million m3 for the entire Holocene. The annual increase in accommodation space within the present confines of the Wadden Sea, resulting from relative sea-level rise, local subsidence related to gas extraction, sand and shell mining, and increases in tidal amplitude, is less than 10 million m3. A comparison of this relatively small volume with calculated short-term annual net sediment dynamics shows that processes transporting sediment in the Dutch part of the Wadden Sea are easily capable to fill new accommodation space. The main factors governing long-term system resilience are the availability of sediment in source areas outside the tidal basin and the capacity of inlets to import this sediment at sufficient rates. Large-scale nourishment is carried out to prevent the Wadden Sea from cannibalizing adjacent island heads and ebb-tidal deltas. The present study may help in fine-tuning this regional nourishment strategy. © Coastal Education & Research Foundation 2013.

Prediction of hydrocarbon column heights in structural traps critically depends on proper analysis of the sealing capacity of faults. Entrainment of clay in fault zones in upper crustal levels may lead to the development of continuous clay smears that dramatically increase the sealing capacity of faults. In this study, direct shear experiments on large-scale samples of layered sandstone-claystone-sandstone are simulated using two-dimensional discrete element numerical models to study the development of clay smears for different claystone types and normal stress conditions. Analysis of clay smear structures in terms of drag, slicing, wear and flow of clay reveals that drag is dominant at low shear displacements and high local stress concentrations, slicing and wear become important at higher shear displacement and low stresses at source bed near the fault zone. Correlation between critical fault displacements in the experiments and local stress ratios (shear stress divided by normal stress) in the models is used to determine smear failure and leakage for all claystones and normal stresses. A smear breach diagram with sealing/leaking conditions for faults containing clay smears shows that clay smears may be sealing at larger displacements than predicted by other fault seal algorithms, such as shale gouge ratio, in particular for low shale content and high normal stress. © 2013 Springer-Verlag Wien.

Chemical interdiffusion of Fe-Mg along the c-axis [001] in natural diopside crystals (XDi = 0.93) was experimentally studied at ambient pressure, at temperatures ranging from 800 to 1,200 °C and oxygen fugacities from 10-11 to 10-17 bar. Diffusion couples were prepared by ablating an olivine (XFo = 0.3) target to deposit a thin film (20-100 nm) onto a polished surface of a natural, oriented diopside crystal using the pulsed laser deposition technique. After diffusion anneals, compositional depth profiles at the near surface region (~400 nm) were measured using Rutherford backscattering spectroscopy. In the experimental temperature and compositional range, no strong dependence of DFe-Mg on composition of clinopyroxene (Fe/Mg ratio between Di93-Di65) or oxygen fugacity could be detected within the resolution of the study. The lack of fO2-dependence may be related to the relatively high Al content of the crystals used in this study. Diffusion coefficients, DFe-Mg, can be described by a single Arrhenius relation with (Formula presented). DFe-Mg in clinopyroxene appears to be faster than diffusion involving Ca-species (e.g., DCa-Mg) while it is slower than DFe-Mg in other common mafic minerals (spinel, olivine, garnet, and orthopyroxene). As a consequence, diffusion in clinopyroxene may be the rate-limiting process for the freezing of many geothermometers, and compositional zoning in clinopyroxene may preserve records of a higher (compared to that preserved in other coexisting mafic minerals) temperature segment of the thermal history of a rock. In the absence of pervasive recrystallization, clinopyroxene grains will retain compositions from peak temperatures at their cores in most geological and planetary settings where peak temperatures did not exceed ~1,100 °C (e.g., resetting may be expected in slowly cooled mantle rocks, many plutonic mafic rocks, or ultra-high temperature metamorphic rocks). © 2013 Springer-Verlag Berlin Heidelberg.

Well abandonment in the context of CO2 storage operations demands a mitigation strategy for CO2 leakage along the wellbore. To prevent possible CO2 transport toward the surface and to protect the wellbore material from contact with acid brine, we propose forming a salt seal around the wellbore at reservoir level, after CO2 injection into a depleted gas field. The mechanism of water evaporation into dry gas and subsequent salting-out of the dissolved halite is a well-known issue in hydrocarbon production. We propose alternating injection of brine and CO 2 to facilitate intentional salt clogging of the reservoir. Salt clogging was studied with TOUGH2, simu-lating multiple cycles of brine and CO2 injection. We developed two near-well reservoir models - a homogeneous 2D model and a more complex heterogeneous 2D model - using certain characteristics of the K12-B depleted gas field. The homogeneous 2D model yields a 50-cm thick salt bank around the well and complete permeability impairment after eight cycles of brine-CO2 injection. Addition of vertical permeability heterogeneities causes variation in the lateral extent of salt precipitation and hence vertical discontinuities in the salt bank. A carefully designed injection strategy - with more injection cycles and lower injection rates - improves the vertical sealing. Predictions of the amount of required clogging for effective sealing would benefit from more accurate porosity-permeability relationships and insights in the long-term stability of the salt bank regarding re-dissolution. We conclude that alternating brine-CO2 injection could be a promising method for intentional salt-clogging of the near-wellbore area. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd.

With the exception of the south of the country, the Netherlands has a strong bipartite hydrogeology: the Holocene part with a coastal dune belt and confining top layer of clay and peat further inland, and the Pleistocene, where thick phreatic aquifers dominate. This research aimed to ascertain the geochemical and palaeohydrological controls on the composition of shallow groundwater in 27 regions. Close to 6000 groundwater analyses were grouped and interpreted in terms of 1. salinity, 2. redox status, 3. acid/base and carbonate status and 4. natural nutrients NH4 and PO4. The a priori classification into geographical regions and geological formations revealed many statistically significant differences in medians, even for geologically or geographically related data groups. The compound-specific interpretation indicates that there are geogenically controlled, systematic differences in groundwater composition at the regional scale. The imprint of the geological sediments on the groundwater composition decreases in the order marine/estuarine via limnological, fluvial to aeolian. The imprints with respect to pH and carbonate status, natural nutrients and redox status are not necessarily interrelated. The vertical stratification in groundwater composition turns out to be often limited at the regional scale due to mutual occurrence of infiltrating and exfiltrating groundwater in regions and either the presence of a highly reactive Holocene, confining top layer or temporal changes in contamination. In the Holocene part, the salinity is controlled by the palaeoenvironmental conditions during the Holocene and by the recharge origin: the average Cl concentration decreases from estuarine via lagoonal to the former Zuider Sea (which was a bay). The most reduced states and also the highest nutrient concentrations and highest CO2 pressure are related to the presence of Holocene marine sediments in the confining top layer. Degradation of marine-derived organic matter as a nutrient source, is likely more intense in the Holocene deposits than that of peat and sedimentary remnants of terrestrial plants. A broad range in pH, carbonate status and redox status is encountered in the Pleistocene part. Here, the palaeohydrological evolution in terms of carbonate leaching together with the geological controls on the calcareous nature of the shallow sedimentary deposits cause regional differences in pH, calcite saturation and silicate weathering. One region with Late Pleistocene limnological deposits has deviating groundwater characteristics and appears more similar to the Holocene part of the Netherlands. Furthermore, reactive Fe is not abundant in all Pleistocene fluvial sediments nor is it maximally mobilised, as not all anoxic groundwater in these sediments is siderite-saturated. This leads to considerable intra- and inter-region variability. © 2013 Elsevier Ltd.

This paper presents a roadmap for the development of a large-scale CO2 transport infrastructure in Europe, between 2020 and 2050, which was defined in the EU FP7 CO2Europipe project. The most important conclusions are related to the finding that the EU CCS transport infrastructure is to be led by a relatively small number of countries, who share the largest burden in the areas of CO2 capture, transport and storage. These include the countries bordering the North Sea, and those countries relying heavily on coal or lignite for their power supply (Germany, Poland the Czech Republic). It is crucial that these countries take the lead and are supported to do so, not only now, but during the whole CCS infrastructure development.

One of the targets of time-lapse seismic monitoring of CO2 sequestration is to determine the parts of the reservoir reached by the injected CO2 and to estimate their saturation. Such information could be extracted from the time-lapse measurement using AVO or impedance information. But non-repeatability of the source positions and time-lapse changes in the overburden could lower the accuracy of the estimation of saturation. We propose the utilization of non-physical (ghost) reflections retrieved by seismic interferometry to estimate the CO2 saturation inside the reservoir. We use the ghost reflections to directly estimate the layer specific velocities inside the reservoir and the cap rock and thus eliminate the two mentioned causes of inaccuracies. We apply this idea and demonstrate its added value and potential using numerically modelled data for a simplified model based on the Sleipner underground storage site in the North Sea.

Reducing CO2 emissions requires an integrated CO2 management approach. The dependency between the different industry sectors is higher than commonly acknowledged and covers all areas; capture, transport, storage and utilisation. TNO is one of Europe’s largest independent research organisations and provides applied science and technical and techno-economic consultancy services in a broad range of areas. TNO supports both industry and governments to develop innovative technologies that reduce emissions, reduce cost and increase efficiency, reliability and availability

A field scale geomechanical model was developed in an early phase of the feasibility study considering geological CO2 storage in a depleted gas field in Poland. Geomechanical model of the gas field was adequate to evaluate the induced stress changes, the geomechanical effects on the top seal and induced surface deformation. The estimated geomechanical effects on the top seal are weak and do not pose a risk for the containment. The effects on the regional sub-vertical faults intersecting the reservoir are not expected to cause fault destabilization, except in the case of partial re-pressurization of non-connected neighbouring compartments. However, the reliability of fault stability assessment is low due to the lack of seismic data that would have made detailed mapping of faults at field scale possible. Our future work will include updating the existing model with a more detailed fault interpretation and dynamic reservoir simulation results when they become available.

Since 2008, CO2 has been injected at the demonstration site for CO2 sequestration in Ketzin, Germany. Since 2009, a permanent array of seismic receivers installed by TNO at the injection site has recorded passive data continuously. It is the intention of TNO to use seismic interferometry (SI) by cross-correlation applied to the recorded ambient noise as a cost-effective technique for time-lapse monitoring. Under specific conditions, SI by cross-correlation can retrieve reflection data that may be interpreted in terms of subsurface layer properties. To assess the feasibility of this monitoring technique, we model base and monitor passive experiments for recording the response from noise sources and cross-correlate the recorded synthetic traces. The best results are obtained when the stationary-phase regions for the Green's functions are sampled densely enough by noise sources and, at the same time, the noise contributions from non-stationary regions cancel to a sufficient extent. Conversely, non-favourable noise conditions will cause wrong retrieval of the Green's functions and possibly deteriorate the monitoring potential of the technique. However, we show that being selective with the recorded noise in terms of illumination characteristics prior to correlation will improve the retrieved reflection data for further monitoring interpretation.

This study presents the results of a basin modeling study covering the cross-border area of the southern Schillground High in the Dutch-German offshore area. A high resolution petroleum system model has been constructed with the aim to evaluate the hydrocarbon generation potential of Carboniferous source rocks and their possible lateral migration of the generated hydrocarbons across the political border. Besides the burial history, temperature and maturity evolution, this model displays for the first time in parallel erosion and salt movement events through time with improved details

During the middle and late Eocene (∼ 48-34 Myr ago), the Earth's climate cooled and an ice sheet built up on Antarctica. The stepwise expansion of ice on Antarctica induced crustal deformation and gravitational perturbations around the continent. Close to the ice sheet, sea level rose despite an overall reduction in the mass of the ocean caused by the transfer of water to the ice sheet. Here we identify the crustal response to ice-sheet growth by forcing a glacial-hydro isostatic adjustment model with an Antarctic ice-sheet model. We find that the shelf areas around East Antarctica first shoaled as upper mantle material upwelled and a peripheral forebulge developed. The inner shelf subsequently subsided as lithosphere flexure extended outwards from the ice-sheet margins. Consequently the coasts experienced a progressive relative sea-level rise. Our analysis of sediment cores from the vicinity of the Antarctic ice sheet are in agreement with the spatial patterns of relative sea-level change indicated by our simulations. Our results are consistent with the suggestion that near-field processes such as local sea-level change influence the equilibrium state obtained by an ice-sheet grounding line.

A Chézy-based hydraulic model was run to estimate the magnitude of extreme floods of Middle Holocene age in the Lower Rhine Valley (Germany). Input parameters were gathered from the field and literature, and used in ten scenarios to calculate a best guess estimate for the minimum size of extreme floods. These events have been registered as slackwater deposits on elevated terrace levels and in a palaeochannel fill. The modelled minimum discharge is 13,250 m3 sec-1 for a Middle Holocene flood with an estimated recurrence interval between 1,250 and 2,500 years. A sensitivity analysis on different input parameters enables evaluation of factors which cause the relatively large range in modelled discharges. Understanding the origin of uncertainties in modelled discharges is important for making geologically based calculations of palaeoflood magnitudes important in modern flood frequency analyses, which generally lack information on the magnitudes of rare events. © 2013 IWA Publishing.

A sea-floor assemblage from hardened sandstone boulders in which lingulid brachiopods predominate is recorded from the Oosterhout Formation near Balgoy (province of Gelderland, the Netherlands). Dinoflagellate cysts indicate a late Early-Late Pliocene (late Zanclean-Piacenzian) age of these boulders; the entire assemblage is indicative of clear marine waters near storm wave base along the southeastern margin of the North Sea Basin at the time. A possible commensal relationship between the lingulid brachiopods and the gastropod Calyptraea chinensis is implied.

CO2 storage is planned in a depleted gas field called P18, which is located offshore in the vicinity of the Dutch coast. This project is also known as the ROAD project, which is the Rotterdam capture and storage demonstration project. In the P18-4 compartment, cold CO2 will be injected into a formation with a temperature of 120°C. Cooling of the reservoir with the cold CO2 will induce thermal stresses, similar to those resulting from injection of cold water. The thermal stresses around the well can promote the propagation of fractures into the reservoir and possibly the caprock. This is usually called thermally induced fracturing. In contrast to cold water injection, for CO2 injection thermally induced fracturing is usually not taken into account. In this paper, we are exploring the potential development of thermal fractures and their impact on the reservoir rock, caprock and well injectivity of the P18-4 reservoir. The P18-4 reservoir was modelled by a modified TOUGH2/ECO2M module. The module is designed for geological storage of CO2 in a wide range of temperature, pressure conditions and therefore different CO2 phase conditions, but was not able to model phase transitions in low pressure – high temperature reservoir. We modified the ECO2M module to be able to model the transition of gaseous to liquid CO2, needed for the pressure temperature conditions investigated in P18-4. To estimate the maximal extent of a fracture into the reservoir we started with 2D simulations of cold CO2 injection without any fracture development in TOUGH2/ECO2M module. The resulting pressure and temperature fields were used in a geomechanical analysis to determine the thermo-elastic and poro-elastic stresses, and to assess the fracture development into the reservoir (using the finite-element software tool DIANA). After completing a number of timesteps, these fractures were introduced back into the TOUGH2 model and the potential injectivity enhancement was analysed. The TOUGH2-DIANA coupling was made semiautomatic, therefore an efficient exchange of data between the two software packages was possible. The DIANA model was initialised with the corresponding stresses at a depth of 2500m, rather than the actual depth of 3200m at which the minimum in-situ stress was too high for any (thermal) fracture to occur. On one side of the cylinder the fracture development was modelled. We employed a layered model representing a quarter cylinder of the reservoir for the TOUGH2 simulations. The model was initialised at 20 bar and 100°C. Injection of 1.1 Mton/yr was assumed, which resulted in a temperature front up to 250 meters into the reservoir after 5 years of injection. The quarter cylinder was mapped upon a 2D plane strain geometry for the geomechanical simulations. The large temperature changes resulted in a fracture development in “the shallow P18-4 reservoir” (2500m depth) of up to 140 m after 5 years of injection. The fracture development was translated into a permeability change in the fractured part of the reservoir and in this way we are able to predict the new injectivity of the reservoir. The injectivity increased from 0.7 Kg/s bar to 2.0 Kg/s bar. In the 2D simulations, we have seen the extent of a fracture in a single-layer reservoir, however this does not completely reflect the vertical heterogeneity in “the shallow P18-4 reservoir”. Also, it was not possible to examine the effect on the caprock with this model. Therefore a 3D model was constructed in both TOUGH2 and DIANA, which resulted in even more shallow P18 reservoir in order to show the ability to simulate the development of a crack inside the caprock. Not only horizontal propagation of the fracture was considered, but also to allow vertical fracture propagation of the fracture into the caprock. The stresses due to the cold injection have to overcome not only the horizontal minimum stress, but also the vertical stress in order to propagate into vertical direction. From the 2D simulations and 3D simulations, it was clear that for the true depth (3200m) of the P18-4 reservoir, no fracturing as a result of the cold CO2 is expected, which is in line with the earlier results. However in “the shallow P18-4 reservoir” (2500m) there is fracture development into the reservoir. The 3D simulation results are very sensitive for the values of the following properties: permeability in the fracture, brine salinity and the reduction of permeability due to salt precipitation. The main impact of thermal fractures are: · Well injectivity increases. · The shape of the CO2 front changes, which means that the cold CO2 can extent much further away from the well than without fracturing. · The probability of the development of fractures in both the reservoir and the caprock increases. · CO2 flow patterns become complicated due to salt precipitation and blocking in the reservoir and/or caprock · The result is very sensitive for the values of the following properties permeability in the fracture, brine salinity and the reduction of permeability due to salt precipitation

Upscaling of reservoir permeability will remain an issue in the oil and gas industry as long as static and dynamic models are limited by computing power and memory constraints. At the same time, flow predictions are required at the scale of the static model. A feasible approach is the subsequent application of upscaling and downscaling: upscaling to be able to make reservoir-scale flow simulations and downscaling to map the results of these calculations on the underlying geological grid. We propose a procedure which mimics the behavior of non-scaled reservoir models better than conventional methods. Our method entails a new non-local upscaling and downscaling procedure inspired by effective medium theories. The most important difference with standard techniques is the choice of boundary conditions. Our boundary conditions are based on the physical situation rather than on an ad-hoc pressure and/or flow condition on the boundaries of the region to be upscaled. We demonstrate our procedure with three examples. The first example entails a simple problem where a 2x2 block region is upscaled and it is shown that conventional procedures break down. The physical explanation is given in terms of a flow disturbance outside the scaled area not honored by these techniques. The second example is a more complicated problem with apparent geological channeling. In the first place, the upscaling provides a good match of the fine-scale dynamic model. Even more important, however, are the downscaled flow velocities resulting when introducing the boundary conditions obtained from the coarse scale for the local fine scale. These show a faithful representation of the channel flow as also obtained with the fine-scale model, while results of attempts to achieve the same with conventional technology did not. The third example is a 3-dimensional model available from the literature. Again, our upscaled and downscaled results were in close agreement with the full fine-scale simulation. The current technique does not account for relative permeabilities and capillary pressures. It may be possible to complement our workflow with already existing techniques for these. This is, however, still a matter of research

A detailed analysis is presented of the short and medium term development of CCS in The Netherlands. Scenarios for CCS development were constructed by combining the most recent estimates of offshore storage capacity, for both depleted gas fields and saline formations, with expected timing and volumes of captured CO2 from two industrialised regions, the Rotterdam harbour area and the Eemshaven area. Individual emitters in both regions were approached to obtain realistic growth profiles for captured volumes. This paper explores the cost of transport and offshore storage of CO2 and explores the benefits of the two regions in joining their storage efforts. Further work is ongoing and will focus on the CCS value chain, to provide the emitters with insight in the cost structure of transport and storage. Furthermore, the study will provide input during the development of a national CCS implementation plan.

Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ13C from diatom carbon (δ13C(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ13C(diatom). Numerous variables can influence δ13C of organic matter in the marine environment (e. g., salinity, light, nutrient and CO2 availability). Here we compare δ13C(diatom) and δ13C(TOC) from three sediment records from individual marine inlets (Rauer Group, East Antarctica) to (i) investigate deviations between δ13C(diatom) and δ13C(TOC), to (ii) identify biological and environmental controls on δ13C(diatom) and δ13C(TOC), and to (iii) discuss δ13C(diatom) as a proxy for environmental and climate reconstructions. The records show individual δ13C(diatom) and δ13C(TOC) characteristics, which indicates that δ13C is not primarily controlled by regional climate or atmospheric CO2 concentration. Since the inlets vary in water depths offsets in δ13C are probably related to differences in water column stratification and mixing, which influences redistribution of nutrients and carbon within each inlet. In our dataset changes in δ13C(diatom) and δ13C(TOC) could not unequivocally be ascribed to changes in diatom species composition, either because the variation in δ13C(diatom) between the observed species is too small or because other environmental controls are more dominant. Records from the Southern Ocean show depleted δ13C(diatom) values (1-4 ‰) during glacial times compared to the Holocene. Although climate variability throughout the Holocene is low compared to glacial/interglacial variability, we find variability in δ13C(diatom), which is in the same order of magnitude. δ13C of organic matter produced in the costal marine environment seems to be much more sensitive to environmental changes than open ocean sites and δ13C is of strongly local nature. © 2012 Springer Science+Business Media B.V.