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Third EAGE CO2 Geological Storage Workshop
- Conference date: 26 Mar 2012 - 27 Mar 2012
- Location: Edinburgh, UK
- ISBN: 978-94-6282-054-8
- Published: 26 March 2012
21 - 40 of 46 results
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CO2 EOR and Storage in Heavy Oil Reservoirs Underlying Permafrost
Authors A. Emadi, M. Sohrabi, A. Farzaneh, M. Jamiolahmady and S. IrlandInjection of the captured CO2 from industrial sources in oil reservoirs can alleviate negative environmental impacts of CO2 emission into the atmosphere and at the same time provides economic rationale for CCS by improving oil recovery. Compared to light oil, heavy oils have a much larger carbon footprint and hence, from environmental point of view, are more attractive targets for CCS. Heavy oil reservoirs are usually produced by thermal recovery techniques which only exacerbates adverse environmental effects of oil production from these reservoirs. Heavy oil reservoirs can therefore be good candidates for combining CCS and EOR. Examples of such reservoirs are found on North Slope, Alaska, where huge heavy oil resources exist in shallow reservoirs at exceptionally low reservoir temperature because of permafrost. This paper presents the results of a series of coreflood studies using a heavy crude sample from a permafrost region. The experiments compare CO2 storage capacity of the rock sample at reservoir conditions under different injection strategies and determine the additional recovery as a result of CO2 injection. The results show that CO2 injection doubled the heavy oil recovery by plain waterflood however the storage capacity of the rock was not significantly affected by the injection strategy.
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Significant Improvement in Oil Recovery and CO2 Storage by Carbonated Water Injection (CWI)
Authors M. Tavakolian, M. Sohrabi, M. Jami and S. IrelandCWI can alleviate many of the shortcomings of conventional CO2 floods. As a single phase (water and dissolved CO2), carbonated water (CW) does not exhibit fingering problem when injected into the reservoir since the mobility contrast between oil and CW is less than what it would be in the CO2-oil system. Consequently, a much better sweep efficiency (compared to CO2 flooding) can be obtained and hence CO2 would be distributed within a larger part of the reservoir. Furthermore, the higher density of carbonated water (compared to water) prevents CO2 gravity override eliminating the risk of leakage of CO2 through cap rock. In this paper, we present the results of a series of coreflood experiments using sandstone cores and real crude oil. The brine used in the coreflood experiments represented Seawater which is usually injected in oil reservoirs. The experiments were carried out to compare the performance of CWI with plain (conventional) water injection and CO2 flooding. The results of both secondary (pre-waterflood) CWI and tertiary (post-waterflood) CWI reveal that CWI is an efficient oil recovery method compared to conventional waterflooding and leads to safe storage of significant quantity of CO2 as a dissolved phase.
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Moving CO2 EOR Offshore
Authors S. Goodyear, M.P. Koster, K.A. Marriot, A. Paterson, A.W. Sipkema and I.M. YoungCO2 is the dominant anthropogenic greenhouse gas that is believed to be driving global warming. Carbon capture and storage (CCS) can contribute to reducing CO2 emissions. However CO2 capture from flue gas sources with current technology is CAPEX and energy intensive, so that the cost of CO2 abatement with CCS is high.
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Compaction Driven Flow in Porosity Waves - A Threat to Caprock Integrity?
By N.S.C. SimonCompaction of porous rock is a mechanism to maintain or increase fluid overpressure and may lead to fluid focusing and the development of porosity waves. Such fluid transport may be much more efficient than Darcy flow or even fracturing and is predicted to play an important role in sedimentary basins, during crustal metamorphism and for mantle melt extraction. Here I investigate the possibility of porosity waves occurring during injection and storage of CO2 in aquifers. Reaction induced compaction may be expected in CO2 storage because of the large thermal, mechanical and chemical disequilibrium that is introduced to the system by human activity, and due to high reactivity of CO2 dissolved in brine. First results indicate that low permeability caprock may fail as a barrier to flow if significant viscous compaction occurs. In laboratory experiments, such deformation has been shown to take place due to the high reactivity of CO2-rich brine. However, the temporal and spatial scales for the onset of focused flow in porosity waves strongly depend on a set of poorly constrained parameters. Thus, more experimental and numerical work and comparison to field data is needed to correctly assess these coupled reaction-deformation-flow processes.
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Fluid Dynamics of CO2 Migration within and out of Geological Storage Reservoirs
By U. WeyerThe obvious discrepancy between Muskat’s (1937) concept and the physics of Hubbert have not yet played a decisive role in Reservoir Engineering as indicated by the huge economic success of the petroleum industry. The geological storage of CO2 is, however, a paradigm changer as reservoir conditions shift from sink conditions during petroleum production to source conditions when geological storage of CO2 is applied. The simulators of the petroleum industry and the methodology used are not well-suited to deal with these source conditions. Hubbert’s Force Potential and Groundwater Flow Systems analysis should be applied in selecting storage sites and in simulating flow paths with mathematical models based on the proven methodology of advanced hydrogeology. Applying correct physics to the long-term migration of CO2 by using existing models of regional groundwater flow determines the eventual discharge points of injected CO2, and the estimated time span involved. If the injection sites are properly selected, then these time spans will exceed thousands or tens of thousands of years before the CO2 would enter surface waters. Geochemical processes will potentially also have significantly reduced the amount of CO2 discharged at that time.
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Association between Discharge Areas of Groundwater and Volcanic CO2
Authors U. Weyer, F. May and J.C. EllisDischarge areas of groundwater flow systems determine the discharge points for CO2, be it of volcanic origin or, in the future, from geological CO2 storage.
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Who are Communicating CCS in Norway?
By A. KlimekBoth engineering approaches and political approaches are crucial if CCS is ever to become a technically functioning option. But both tend to reduce CCS to a mere technical or political problem. Carbon capture is afflicted with an increasing complexity and I argue that it cannot be understood or even explained in a single way. If a new e. g. technology shall be implemented you have to make sure that you will not encounter resistance. A various number of theories offer good examples and ways to inform or even involve the public into implementation processes. Again and again it gets visible that the ‘general public’ is more than a homogenous crew, where decision processes can calculate by means of graphics. The general public needs more than just information. Various implementation processes demonstrate that new technologies can collapse without public benefit.
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Fracture-related Fluid Flow in Sandstone Reservoirs - Insights from Outcrop Analogues of South-eastern Utah
Authors K. Ogata, K. Senger, A. Braathen, J. Tveranger, E. Petrie and J.P. EvansFault- and fold-related fractures influence the fluid circulation in the subsurface, thus being of high importance for CO2 storage site assessment, especially in terms of reservoir connectivity and leakage. In this context, discrete regions of concentrated sub-parallel fracturing known as fracture corridors are inferred to be preferential conduits for fluid migration. We investigate fracture corridors of the middle-late Jurassic Entrada and Curtis formations of the northern Paradox Basin (Utah), which are characterized by discoloration (bleaching) due to oxide removal by circulating CO2- and/or hydrocarbon-charged fluids. The analyzed structures are located in the footwall of a km-scale, steep normal fault with displacement values on the order of hundreds of meters. They trend roughly perpendicular and subordinately parallel to the main fault direction, and define a systematic network on the hundreds of meters scale. The fracture corridors pinch- and fringe-out laterally and vertically into single, continuous fractures, following the axial zones of open fold systems related to the evolution of the main fault. Based on the presented data we hypothesize that such fracture corridors, connecting localized reservoirs at different stratigraphic levels up towards the surface, represent preferred fluid migration pathways rather than the main faults.
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Impact of Faults on the Mechanical and Petrophysical Properties of Sandstone Reservoirs - An Implication for CO2 Storage
Authors R.A. Alikarami, A.T. Torabi and E.S. SkurtveitTo assess reliable candidate reservoirs/aquifers for CO2 storage, enhanced understanding of the structure and the mechanical and petrophysical properties of strain localization zones in comparison to the surrounding undeformed rock is essential (Torabi 2007). To understand the possible effect of deformation structures on CO2 storage, a fieldwork was performed in the Navajo and Entrada sandstones in southeastern Utah to investigate the elastic and petrophysical properties of a fault core and damage zone. Deformation structures, air permeability and rock hardness have been logged along scan-lines perpendicular to the fault. In the foot-wall fractures are observed just within distance of three meters from the fault, but deformation bands are spread to about hundreds of meters. In the hangingwall fractures are observed in a distance of more than seventy meters, while deformation band have been concentrated within forty meters from the fault. Our preliminary results show a strong correlation between deformation structures intensity and distance from the fault, but weak correlation between Schmidt Hammer rebound and mini-perm values versus deformation pattern. The spread in the measured data might be related to variation in internal layering in the sand dunes, the orientation and weathering of the surface used for testing or other structural effects.
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Experimental and Modelling Study of the Dry-out during CO2 SC Injection in Reservoir Rock from the Hontomín Site (Spain)
Authors F. Grandia, A. Credoz, J. Torres, R. Solanas and L. VegaThe dry-out effect due to the dissolution of brine in CO2sc has been identified experimentally using samples from the reservoir formations at the Hontomín site. Injection of CO2 in this site is planned in 2013 in the frame of the OXYCFB300 EC-funded project. Samples from the Arcera Fm. have been selected for the experiments, and filled with NaCl-type brine. After 3 hours of injection of supercritical CO2 at 120 bar and 80 ºC, precipitation of halite is triggered leading due to dissolution of brine into CO2. This leads to permeability reduction in the first centimetres from the injection point. These experimental results have been reproduced in a reactive transport simulations using TOUGHREACT.
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Investigating the Link between Surface Deformation and Microseismicity Using Coupled Flow-geomechanical Simulation
Authors D. Angus, T. Lynch, P. Lorinczi and Q.J. FisherIn this paper, we investigate the relationship between surface deformation and microseismicity using coupled fluid-flow and geomechanical simulation. Since both microseismic and InSAR monitoring integrated with coupled fluid-flow/geomechanical modelling represent cost effective approaches in monitoring the containment of injected CO2, it is worthwhile exploring any potential link between microseismicity and surface deformation. Specifically, we simulate and examine the temporal and spatial evolution of microseismicity (see Angus et al., 2010) and surface uplift due to injection of CO2 for a faulted graben style sandstone reservoir model. We attempt to address whether there is a significant link between surface uplift and microseismicity, and if so, can we draw some relationship between rates of surface uplift and seismicity?
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Estimation of Thermodynamics and Chemical Kinetics Parameters at Different Scales for the Models of CO2 Storage
Authors J. Raveloson, D. Garcia, C. Helbert and B. GuyThe present work is based on the study of the water-gas-rock interactions in the case of CO2 storage in geological environment. The focus is on the scale of observation geochemical phenomena while taking into account the heterogeneity of the reservoir. This heterogeneity at small and large scale helps to maintain a local variability of the chemical composition of the fluid and influence reaction rates at the pore as well as at the reservoir scale We propose to evaluate the geostatistical characteristics of local variability thanks to simulations of reactive transport on a small scale in which parameters (namely the equilibrium constants log K and the rate constant k) are perturbed to represent local processes.
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Corrective Measures
By M. KosterWhen a CO2 store has been found to be leaking, one would expect immediate action to be taken. It is however important to first establish the exact migration path through the store. This is then followed by a risk assessment, which addresses the potential magnitude and consequences of the leak, before deciding on any appropriate actions to remedy the problem.
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Modelling the Reflectivity of a Carbon Dioxide Transition Zone
Authors J.L. Gomez and C.L. RavazzoliThe seismic monitoring of carbon dioxide in geologic reservoirs is mostly focused on the characterization of accumulations of high saturation, due to their large seismic amplitudes. Nevertheless, low-saturation zones with dispersed CO2, or saturation transitions may have an important role in the propagation of waves within the reservoir, giving rise to amplitude and phase changes of the seismic signals. In this work, we consider a transition layer given by a linear CO2 saturation-depth profile, which in turns develops a non-linear velocity trend with depth. We model the theoretical reflectivity response of a simple reservoir model, based on the Sleipner field, with a given CO2 saturation transition zone. Our study entails a parametric analysis of the generalized P-wave reflection coefficient and its variations with ray angle (AVA) and frequency (AVF). Our results suggest that the characterization of CO2 transitions zones can be achieved with a combined AVA and AVF analysis. We have shown that discrimination between thin and thick CO2 zones seems feasible. In addition, the bulk CO2 saturation present in the reservoir may be estimated by considering its reflectivity in the frequency domain.
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SCAL Programme for Goldeneye CO2 Storage
Authors S. Goodyear, W. Boom, P. Doe, A. Cable and D. MogfordSCAL data is an important input to the assessment of the Goldeneye reservoir for CO2 storage. A CO2 storage specific SCAL programme was undertaken comprising three stages: development of a conceptual framework for the displacement mechanisms; review of existing Goldeneye SCAL data and execution of a new SCAL tests. The high vertical permeability of the main sand and the aquifer influx under depletion required a non-standard set of measurements to be specified.
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CO2 Field Lab - Field Experience with Controlled Releases of CO2 at very Shallow Depths
Authors D. Jones, J.F. Girard, O. Kuras, E. Lindeberg, M Barrio, K. Royse, F. Gal, P. Meldrum, P. Pezard, A. Levannier, J. Desroches, D. Neyens, J. Paris and G. HenryThe objective of the CO2 Field Lab project is to determine the sensitivity of monitoring systems to detect shallow CO2 migration and surface leakage. To achieve its objectives, the project comprises two controlled releases of CO2 into the shallow and very shallow subsurface in a Norwegian aquifer in the Svelvik ridge (Figure 1).
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Microseismic Monitoring of CO2 Storage
Authors A. Stork, J. Verdon and J.M. KendallGeomechanical deformation, if it creates and/or reactivates faults and fractures, can provide a leakage pathway for CO2 to escape the reservoir. By monitoring microseismicity in and around the reservoir, the risks of leakage can be assessed. Although it is a mature technology for monitoring hydraulic fracturing in tight gas reservoirs, microseismic monitoring is still an experimental technique for CCS. To be of use for CCS sites, arrays must be capable of detecting events must across a wider area than typical frac-jobs. This poses a challenge to design suitable arrays within engineering and cost constraints. Another key issue is to determine how microseismic observations should be best interpreted with respect to leakage risks. So far we have found that linking event observations with geomechanical models - comparing predictions from various geomechanical scenarios with field observations - is an important aspect of event interpretation. In this paper we use a case example from the Weyburn CCS project, although our discussions have general application.
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An 'Inverse CCS Site' in NW Hungary – Geology and Modeling
Authors C.S. Király, M. Berta, Á. Szamosfalvi, G. Falus and C. SzabóThe research of natural analogues for future CCS projects is a dynamically growing sector of geoengineering. In our work this newly discovered aspect of a CO2 field is presented. In NW Hungary there is a field utilized for more than 60 years. Thus there is a large amount of data from hydrocarbon exploration, gas measurements, seismic sections, well logs, and porewater analysis. Modelling work is done to describe the interactions resulting in the experienced situation to provide an estimate for a planned CO2 reservoir similar to this natural analogue in pressure, temperature, hydrogeology, tectonics, and composition.
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The Effects of Aquifer/Caprock Interface on CO2 Storage Capacity and Security
Authors S.M. Shariatipour, G.E. Pickup, D. Stow and E.J. MackayIn simulations of CO2 storage in saline aquifers, it is often assumed that there is a sharp boundary between the aquifer and the caprock. However, this is not always the case. In many cases there is a gradual transition between sand-rich facies in the aquifer and mud-rich facies in the caprock. Moreover, some simulations assume a smooth interface, whereas typically the surface is irregular, due to sedimentological and stratigraphic effects or structural deformation. We have conducted a range of numerical simulations on a variety of heterogeneous aquifer/caprock models to investigate the impact of the different types of aquifer/caprock interfaces. Firstly, the nature of the interface can influence estimates of storage capacity. A transition zone between the aquifer and the caprock leads to uncertainty in the effective aquifer volume. Secondly, the aquifer/caprock interface can affect the security of CO2 storage. A transition zone can increase the security by providing partial baffles to hinder CO2 migration towards the caprock. Rugosity at the aquifer/caprock interface, may assist or hinder structural trapping. Small domes may provide extra storage volume. On the other hand, topographical highs may provide pathways for rapid migration of CO2 from the injector.
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Laboratory CO2 Migration Experiments for Evaluation of Potential Storage Sites in the Czech Republic
Authors V. Havlova, D. Dobrev, P. Bruha, V. Hladik, V. Kolejka and M. GeršlResearch activities within the presented project aimed at development of methodology for studying CO2 migration in reservoir rocks and caprocks under Czech Republic conditions. As the storage system cannot be observed directly in-situ, lab experiments should simulate the underground conditions as well as possible. This goal can be achieved only by maintaining the simulated injection conditions during the experiment course. This approach was the key element in the presented R&D work. The first achievement of the presented research was collection of information about potential storage sites in the Czech Republic, achievement of sample for candidate host rock type and their characterisation. Based on preliminary site selection and also on the availability of suitable cores, reservoir rocks from 3 geological structures were selected for the experiments: Carboniferous sandstones from the Central Bohemian Basin and 2 Neogene type sandstones from Vienna Basin, S. Moravia. Simultaneously a high pressure flow-through migration apparatus was successfully constructed, enabling dynamic laboratory experiments with supercritical CO2, reservoir rock samples and brines under reservoir p-T conditions. The device allows also measurements of sample permeability for water prior or after the CO2 migration. A set of experiments with rock samples was performed and evaluated.
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