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Fifth CO2 Geological Storage Workshop
- Conference date: November 21-23, 2018
- Location: Utrecht, Netherlands
- Published: 21 November 2018
1 - 20 of 58 results
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Exploring Geophysical Applications For Distributed Acoustic Sensing (DAS) Using A Flexible Interrogator Research Platform
Authors P. Thomas, E. Kolltveit, Y. Heggelund, M. Wilks, A. Wuestefeld, K. Midttømme and M. LandrøDAS continues to be a promising and cost-effective technology for carbon storage monitoring applications including systems that monitor geological changes using active seismics, and also for passive mode operations, e.g. the monitoring of microseismic activity during CO2 injection. The authors have developed a DAS interrogator research platform that has enabled a better understanding of the critical equipment architecture and experimental factors influencing the collection and analysis of DAS data. The authors plan to test this at different CCS pilot installations. In the future, the performance and functionality of the DAS interrogator research platform will be expanded, and techniques for applying it developed further in order to meet CCS specific needs determined from wider collaboration.
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High Resolution Modelling And Steady-State Upscaling Of Large Scale Gravity Currents In Heterogeneous Sandstone Reservoirs
Authors S. Jackson, I. Mayachita and S. KrevorSummaryWe investigate the impact of small-scale heterogeneities (<10m) and gravity on large scale O(100m) lateral CO2 plume migration at varying capillary number, Nc and gravity number, Ngv. For isotopically correlated heterogeneities, plume migration was slowed signicantly at low Nc and high Ngv. For anisotropic cases akin to sedimentary geological structures, the plume speed was correspondingly enhanced, with breakthrough times reduced by up to 20% at large correlation lengths. Using relative measures, the capillary pressure was found to be the major control on plume migration as opposed to permeability, at low Nc. Using single, homogenized upscaled functions, we were able to capture the effects of small scale heterogeneities at low or high Nc and moderate Ngv. However, the relative enhancement of the impact of heterogeneities at high Ngv (and low Nc) could not be captured using single homogeneous functions for the entire domain. Without including enhanced gravity effects in the upscaling procedure, which generate anisotropic upscaled functions, the full effects of small-scale heterogeneities in gravity segregated flow could be signicantly underestimated in large scale models, leading to inaccurate plume migration estimates.
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Identifying Hidden Risk Elements For CO2 Storage From Reprocessed Seismic Data
Authors S. Carpentier, H. Abidin, P. Steeghs and H. VeldkampSummaryCO2 storage needs economic business cases through cost-effective exploration and production and needs license-to-operate through public support. Re-interpretation and reprocessing of vintage geophysical data is a means to achieve cost-effective exploration whereas de-risking and conformance control of storage operations is a means to obtain public support. Seismic exploration should identify risk elements for CO2 storage such as the risk of leakage, risk of pressure build-ups or drops, unexpected increase or decrease of storage capacity and spill points to name a few. These risks elements are often caused by hidden features such as a failing overburden seal, closed or open faults in either reservoir or seal and high- or low-permeability streaks in the reservoir. We have investigated a seismic reprocessing workflow for imaging and de-risking CO2 storage reservoirs and seals. The workflow includes statics, demultiple, velocity modeling, Prestack Time Migration, high resolution sparse spike deconvolution and Non Local Means filtering. Non Local Means filtering increases signal to noise ratio while preserving edges and the sparse spike deconvolution produces results with superior vertical and lateral resolution. This workflow manages at low cost to considerably de-risk the CO2 storage reservoirs and seals by identifying previously hidden faults, seal-reservoir contacts and thin reservoir streaks.
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Petrophysical Analysis And Rock Physics Diagnostics Of Sognefjord Formation In The Smeaheia Area, Northern North Sea
Authors N.H. Mondol, M. Fawad and J. ParkSummaryThis study focuses on petrophysical characterization and rock physics diagnostics of the reservoir sandstones of Sognefjord Formation in the Smeaheia area that penetrated by an exploration well 32/4-1. The large scale CO2 storage site “Smeaheia” is located east of the Troll field in the Stord Basin. The CO2 storage formation is identified within a fault block bounded by major faults to the north, east and west, where the faults system in the east is the Øygarden Fault Complex and the fault to the west and north is the Vette Fault. The storage formation has pinched out towards the south. Petrophysical analysis and rock physics diagnostics suggest that the reservoir sandstone is uncemented and has good to excellent reservoir quality. The reservoir sandstone can be subdivided into three zones where the lower unit (Zone-3) has an excellent reservoir quality (high porosity, high permeability and less clay content) compared to the upper unit (Zone-1 and Zone-2). The two carbonate stringers are present in Zone-3 interpreted as extremely high resistivity, high density, high Vp and low porosity/permeability units which could be flow barriers based on their lateral extent.
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Impact Of Time-Dependent Wettability Alteration On Dynamic Capillary Pressure
More LessSummaryIn many applications, the wettability of the rock surface is assumed to be constant in time and uniform in space. However, many fluids are capable to alter the wettability of rock surfaces permanently and dynamically in time. We simulate the dynamic system using a bundle-of-tubes (BoT) approach, where an empirical model for contact angle change is introduced at the pore scale. The resulting capillary pressure curves are then used to correlate the time-dependent term to the upscaled version of the wettability model. This study shows the importance of time-dependent wettability for determining capillary pressure over timescales of weeks and months. The impact of wettability has implications for experimental methodology as well as macroscale simulation of wettability-altering fluids.
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The Longyearbyen CO2 Lab Project: Lessons Learned From A Decade Of Characterizing An Unconventional Reservoir-Caprock System
Authors S. Olaussen, K. Senger, T. Birchall, A. Braathen, S. Grundvåg, Ø. Hammer, M. Koevoets, L. Larsen, M. Mulrooney, M.B. Mørk, K. Ogata, S. Ohm and B. RismyhrSummaryThe UNIS CO2 Lab has evaluated the subsurface near the local coal-fueled power plant in Longyearbyen, Svalbard, Norway as a possible CO2 storage site. Extensive geological and pressure studies, including eight fully cored slim boreholes have proven a nearly 400 m thick shale dominated unit as an efficient cap rock for buoyant fluids. The underlying 300 m thick fractured and under-pressured heterolithic succession is identified as a potential unconventional reservoir The study concludes that the reservoir exhibits injectivity and storage capacity that are sufficient for the relative small volume of the CO2 emitted from the coal power plant.
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Norway CCS Demonstration Project: Evaluation Of Jurassic Reservoirs For Safe CO2 Injection And Storage
By F. RiisSummaryIn July 2018, the Ministry of Petroleum and Energy (MPE) offered an area in the northern Stord Basin for applications to exploit a subsea reservoir for injection and storage of CO2. This will be the first licence regulated by the Norwegian regulation for CO2 Storage (2014). By offering the area south of the Troll Field for an exploitation licence, it was decided to continue with the qualification of the Johansen-Cook aquifer for the Northern Light project.
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Reactive Transport Modeling For CO2 Sequestration With A Dual Mesh Method
Authors D. Guérillot and J. BruyelleSummaryAcidic fluid injection in rock formations may generate geochemical reactions that can modify the mineral assemblage of the rock and disturb thermodynamic equilibria. Numerical difficulties of reactive transport simulation are that geochemical reactions are at the pore scale, may appear in short time period and are very sensitive to the mesh size and/or time step. The classical approach for reservoir engineers consists in upscaling the high resolution petrophysical values to assign to a low-resolution model. For reactive transport modelling, the upscaling step will impact not only the mass fraction of each species but also the mineral dissolution and/or precipitation processes that highly depend on mass fractions. This paper recalls the Compositional Dual Mesh Method, an original algorithm for a compositional flow modelling in porous media with rock-fluid interactions using two different space and time discretization: one mesh, as usual for the pressure equation and a much finer one for the chemical reactions. The interest of this scheme is that the calculation of the flow on the high-resolution grid is done solving a local problem on each coarse cell. Two examples of CO2 injection in carbonate reservoirs illustrate this algorithm.
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Numerical Study Of Microbially Induced Calcite Precipitation As A Leakage Mitigation Solution For CO2 Storage
Authors S. Tveit, S.E. Gasda, H. Hægland, G. Bødtker and M. EleniusSummaryIn this abstract, we develop simulation models to study and show the potential for field-scale application of microbially induced calcite precipitation (MICP) as a leakage mitigate solution in CO2 sequestration. Based on laboratory experiments, field-scale cases, and numerical studies from the literature, two injection strategies for efficient MICP are developed: (I) injection of pre-stimulated microorganisms and urea into the subsurface, resulting in calcite precipitation around the body of the microbes; and (II) the classic approach of injecting microorganisms together with chemicals to stimulate growth of biofilm, and subsequent calcite precipitation from the biofilm. To enable field-scale simulations of (I) and (II) at low computational cost, we simplify the processes that have little contribution to the flow, while keeping input parameters and assumptions as realistic as possible. The injection strategies were simulated on field-scale, synthetic 2D radial models. The simulation results showed that both injection strategies produce significant porosity/permeability decrease at targeted locations away from the injection well. Moreover, it was seen that injection strategy (II) produced significantly more porosity/permeability decrease compared to (I).
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Smeaheia, A Potential Northern North Sea CO2 Storage Site: Structural Description And De-Risking Strategies
Authors M.J. Mulrooney, J. Osmond, E. Skurtveit, L. Wu and A. BraathenSummarySmeaheia is a potential subsurface CO2 storage site located on the Horda platform in the Norwegian sector of the North Sea. The site is currently being investigated as part of the Norwegian CCS Research Centre, which envisages injection, and storage of CO2 into shallow-marine deposits comprising the Jurassic Viking Group. Two prospects, defined as fault-bound structural closures, have been identified, i) Alpha in the footwall of the Vette fault, and Beta in the Hanging wall of the Øygarden fault. In this contribution we present the fundamental structural framework of the Smeaheia site as derived from seismic interpretation of a high resolution 3D dataset. Qualitative and quantitative fault seal properties of the Vette fault are presented. Juxtaposition and shale gouge ratio analysis suggest the Vette fault has a high sealing probability for the Alpha closure. A relay zone to the south of the structure is more likely to be non-sealing and may facilitate pressure communication with a neighbouring fault block where hydrocarbon production has been ongoing. This communication may have resulted in Smeaheia being depleted. Risk of fault reactivation is assessed based on likely in-situ stress states, hydrostatic pressure regimes and the aforementioned depleted pressure regimes.
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Experimental And Theoretical Investigation Of Natural Convection In CCS: Onset Time, Mass-Transfer Rate, Capillary Transition Zone, And Heat Of Dissolution
Authors A.A. Eftekhari, R. Farajzadeh and H. BruiningSummaryWe study the enhanced mass transfer of CO2 in water for a CO2 saturated layer on top of a water saturated porous medium, experimentally and theoretically. A relatively large experimental set-up with a length of 0.5 m and a diameter of 0.15 m is used in pressure decay experiments to minimize the error of pressure measurement due to temperature fluctuations and small leakages. The experimental results were compared to the theoretical result in terms of onset time of natural convection and rate of mass transfer of CO2 in the convection dominated process. In addition, a non-isothermal multicomponent flow model in porous media, is solved numerically to study the effect of the heat of dissolution of CO2 in water on the rate of mass transfer of CO2. The effect of the capillary transition zone on the rate of mass transfer of CO2 is also studied theoretically. The simulation results including the effect of the capillary transition zone show a better agreement with experimental results compared to the simulation result without considering a capillary transition zone. The simulation results also show that the effect of heat of dissolution on the rate of mass transfer is negligible
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CO2 Flow, Alteration And Geomechanical Response In Confining Units – An Experimental Approach
Authors E. Skurtveit, A. Sundal, M. Soldal, G. Sauvin and T.I. BjørnaråSummarySeal integrity during injection operations is a topic of great interest both within the CO2 storage community, for wastewater injection and traditional reservoir pressure support. The Little Grand Wash fault, central Utah, USA, provides an excellent location for studying seal bypass systems in a siliciclastic sedimentary sequence. Two mode I siltstone fractures with significantly different apertures and varying degree of sample bleaching due to alterations from reactive fluid flow are studied together with two intact rock reference samples from the same depth level in the core. The experimental work addresses fracture flow and stiffness relationships. Observed differences in fracture closure trends may be explained as a rapid decrease in stiffness and flow for altered samples due to the fluid rock interaction process altering the fracture surface contact area for this sample.
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Laboratory-Scale Study On The Swelling Behaviour Of Coal Due To CO2 Injection
Authors F. Bertrand, O. Buzzi and F. CollinSummarySorption- and stress-induced coal permeability alteration may occur considering injection of carbon dioxide in coal seams for CCS. To take into account properly these phenomena, a microscale model was developed for the modelling of injection experiments carried out in laboratory. This work presents this model and first experimental results obtained from an injection test.
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Time-Lapse Separation Of Fluid And Pressure Effects With An Arbitrary Fluid Mixing Law
More LessSummaryTime-lapse seismic is a tool widely used for reservoir management. A common challenge is to isolate the effect of pore pressure and saturation changes in the 4D signal. This is an obstacle not only for hydrocarbon reservoirs: CCS projects also demand monitoring, to ensure that the injected CO2 remains stored in the target interval and that there is no abnormal pore pressure build-up. The way fluids mix in the pore space has a significant impact on the effect of saturation changes in the 4D signal, and uncertainties in this mixing propagate into the estimations of pressure and fluid changes from time-lapse data. Homogeneous mixing is usually assumed to be a reasonable approximation of the fluid behavior. In this study, we will make no such assumption, but rather set the mixture law as a degree of freedom in an inversion scheme. We model different CO2 saturations and pore pressures, which we combine with a rock physics model to obtain different synthetic reflectivities and time-shifts. From these modeled seismic measurements, we try to recover the changes in the reservoir parameters. We compare the results obtained with our method against those under failed assumptions about the fluid mixture law.
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Reservoir Characterisation Of Johansen Formation As Potential CO2 Storage Reservoir In The Northern North Sea
Authors M. Fawad and N.H. MondolSummaryTo evaluate subsurface reservoirs for CO2 sequestration, the grain scale properties and role of diagenesis is important for the injectivity and the subsequent mobilization. This study focuses on Johansen Formation of Jurassic age in the vicinity of Troll field within the northern North Sea. Johansen Formation is a saline aquifer and no hydrocarbon discovery has been reported in this reservoir so far. We analysed 24 wells using petrophysics and rock physics techniques to obtain net reservoir, net to gross ratio, effective porosity, volume of shale and level of cementation, and attempted to relate these parameters with the factors influencing them. The reservoir properties were found to be optimal approximately around depths shallower than 2000m (below sea floor, BSF). Even the shallowest sandstones exhibited cementation indicating calcite precipitation while the sediments deposited. Presence of shale however found to inhibit the quartz cementation possibly preserving the porosity. These findings will help understanding the complexity of the Johansen Sandstone as storage reservoir and the influence of heterogeneity on CO2 migration.
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Quantifying The Risk Of CO2 Leakage Along Fractures Using An Integrated Experimental, Multiscale Modelling And Monitoring Approach
Authors K. Bisdom, M. Dean, J. Snippe, N. Kampman, A. Busch, S. Zihms, F. Doster, R. March, P. Bertier, H. Claes, R. Fink, B. Krooss, S. Hurst, A. Lidstone and P. van RossumSummaryExisting CO2 storage sites have illustrated that intact low-permeability mudrocks are effective barriers to avoid upward migration of CO2 from the storage complex. However, widespread deployment of Carbon Capture and Storage (CCS) as a means of climate change mitigation requires gigaton-scale CCS, rather than the few current megaton projects, to be deployed near large point sources of CO2. In the future, geological storage sites with faulted caprocks cannot always be avoided. We therefore need to rigorously assess geological leakage risks for CCS and specifically improve our understanding of multi-phase fluid migration in faulted and fractured caprocks. The DETECT research program will provide new insights by integrating experimental characterization with multiscale modelling of the combined hydrochemical, hydromechanical and clay swelling and shrinking effects in faulted and fractured mudstones. The purpose of the models is to establish determine realistic flow rates across fractured and faulted mudstone caprocks, to identify existing monitoring tools capable of detecting such fluid migration. Based on these quantitative leakage scenarios, risk and mitigation bow-tie analyses are developed with which suitable and cost-effective monitoring tools can be identified.
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Feasibility Study Of Quantifying Porosity From Seismic Data In Smeaheia
Authors R. Dehghan-Niri and R. Prakash SrivastavaSummaryEquinor with Shell and Total, evaluate the feasibility for full-scale CO2 capture and storage project in Norwegian continental shelf. One of the challenges for CO2 storage sites is to assure containment and to assess possible leakage paths to the surface. Understanding the overburden’s geological setting is crucial for this assessment. As part of the overburden risk assessment, we investigate the potential for quantifying porosity from seismic inversion data. Knowledge of the porosity distributions, may enable us to employ porosity-permeability models in the future to assess leakage pathways into the overburden.
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Monitoring Of CO2 Leakage Using High-Resolution 3D Seismic Data – Examples From Snøhvit, Vestnesa Ridge And The Western Barents Sea
SummaryInjection of CO2 in subsurface reservoirs may cause overburden deformation and CO2 leakage. The aim of this study is to apply technologies for detection and monitoring of CO2 leakage and deformation above the injection reservoirs. The examples of this study include data from the Vestnesa Ridge natural seep site, the Snøhvit gas field and CO2 storage site region, and the Gemini North gas reservoir. Reprocessing of existing 3D high-resolution seismic data allows resolving features with a vertical and lateral resolution down to c. 1 m and c. 5 m respectively. The current acquisition systems could be modified to image structures down to one meter in both the vertical and horizontal directions. We suggest a monitoring workflow that includes baseline and time-lapse acquisition of high-resolution 3D seismic data, integrated with geochemical, geophysical, and geotechnical seabed core and water-column measurements. The outcome of such a workflow can deliver reliable quantitative property volumes of the subsurface and will be able to image meter-sized anomalies of fluid leakage and deformation in the overburden.
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Investigating The Impact Of Relative Permeability Curves On Cold CO2 Injection
Authors M. Abbaszadeh and S. ShariatipourSummaryDifferent injection methods have been already proposed by different researchers to improve the solubility of CO2 in the formation brine. In this study an injection technique is presented to cool down (liquefy) the supercritical CO2 in the wellbore by the use of a downhole cooler equipment. CO2 with a higher temperature enters the cooling equipment and exits the equipment with a lower temperature at the down-stream in a same injection pressure. The colder (liquid) CO2 has a higher solubility in brine, higher density and viscosity which increases the security of CO2 storage. With this method the supercritical CO2 is cooled down to a liquid phase to increase the solubility at the wellbore and thus it eliminated the risk of phase change or pressure and rate fluctuation in liquid CO2 injection from the surface. To simulate this technique two cases have been considered by changing the relative permeability curves. The results show that using the combination of CO2STORE and THERMAL options shows a higher dissolution compared with only inserting the relative permeability curves corresponding the injection condition.
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Opening Versus Self-Sealing Behaviour Of Single Fractures In Mudstone Caprocks During CO2 Migration
By N. KampmanSummaryReactions between CO2 and CO2-charged brines and mudrocks may inhibit CO2 leakage via the precipitation of carbonate minerals or via swelling of clay minerals or enhance leakage via the corrosion of carbonate cements. The timescales for the potential self-sealing behaviour, and/or the magnitudes of the permeability enhancements are uncertain. Laboratory experiments can provide constraints on the intrinsic fracture permeabilities, but the quantification of permeability changes following reaction or under conditions of multiphase flow is challenging in the laboratory. Reactive transport modelling (RTM) provides a numerical laboratory in which the intrinsic permeabilities of rough fractures, and the coupling of the flow and reaction processes, can be investigated. A modified local cubic law (MLCL) is used to model rough fracture permeability, and coupling of permeability-porosity changes to mineralization and clay swelling. The results show that the intrinsic permeability of self-affine fractures is primarily dependent on the roughness and degree of correlation between the two fracture surfaces, and that with increasing roughness the simulated fracture permeabilities are systematically lower than permeabilities predicted from the fracture aperture mean using a cubic law. The dependence of fracture permeabilities on reactions is investigated, and the relationship between mineralization behaviour and fluid residence time is discussed.
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