http://precedings.nature.com/collections/virtual-climate-conference/ Recently posted documents in Virtual Conference on Climate Change and CO2 Storage Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://dx.doi.org/10.1038/npre.2008.2661.1 While mature oil reservoir and aquifers are good candidates for CO2 sequestration, we proposed and investigated the alternative approach which, at the very start of production, combines CO2 sequestration and CO2 EOR in gas condensate reservoir. Firstly, we conducted compositional reservoir simulation and synthetic seismic simulation in a five-spot well pattern to investigate whether seismic data can monitor of CO2 front and gas condensate bank. The simulated results and the seismic simulation results are compared with each other. Although the density contrast among reservoir gas, injected CO2 and condensate is smaller than the density contrast in the case of CO2 sequestration in aquifer, the seismic signal can capture this smaller difference and monitor the CO2 injection front and locate the condensate zone. When there is no adequate data available for reservoir characterization at early period of production, this direct measurement is very valuable for reservoir characterization and for any stimulation of condensate block. Secondly, we compare the production by natural depletion and production combined CO2 EOR and storage at the very beginning. The latter will speed up the recovery process, increase the recovery rate while simultaneously store CO2 in reservoir. The extra benefit in gas condensate reservoir is that injection of CO2 will increase the pressure and postpone and decrease liquid dropout and relieve the condensate blocking. http://dx.doi.org/10.1038/npre.2008.2661.1 Mon, 15 Dec 2008 20:00:36 UTC The compositional simulation and seismic monitoring of CO2 EOR and sequestration in new gas condensate reservoir doi:10.1038/npre.2008.2661.1 2008-12-15 Chengwu Yuan Nature Precedings 2008-12-15T20:00:36Z Presentation Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2636.1 Within the scope of producing clean fossil fuels by simultaneously tackling greenhouse gas emissions, the interfacial tension of partially miscible phases containing CO2 is being investigated with the pendant drop method. Emphasis is given to measurements at elevated pressures and temperatures, analogous to reservoir conditions. A high pressure apparatus consisting of a view cell and high pressure capillary fittings is used for creating pendent drops at the desired conditions. A computer aided Drop Shape Analysis system is used for capturing images of such drops, which are then analysed for the interfacial tension calculation of the two phases with the KRUSS DSA software. The results acquired from the initial measurements conducted for the H2O/CO2 system are presented in comparison with literature data. http://dx.doi.org/10.1038/npre.2008.2636.1 Fri, 12 Dec 2008 17:34:45 UTC Pendent Drops at Elevated P & T doi:10.1038/npre.2008.2636.1 2008-12-12 Apostolos Georgiadis Nature Precedings 2008-12-12T17:34:45Z Poster Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2649.1 Acquiring a comprehensive understanding of the behaviour of carbon dioxide under reservoir conditions is essential for optimizing its usage in enhanced oil recovery (EOR) and for developing sequestration schemes. In order to obtain this understanding, it is necessary to study the physical properties and phase behaviour of mixtures of carbon dioxide with hydrocarbons and brines under conditions of high pressure. In this work we are addressing both the experimental and the theoretical aspects of this problem. A new apparatus, based on the static-analytical method, has been developed to measure phase equilibrium. The equipment comprises a high-pressure cell with sapphire windows for visual observation and phase sampling, with on-line gas chromatography analysis, for measuring the phase compositions. The experimental work is complemented with a theoretical modelling for these mixtures, using the statistical association fluid theory for potentials of variable range (SAFT-VR). As an example of the predictive capabilities of the equation, the fluid phase behaviour of the mixture (carbon dioxide + n-decane) is presented. http://dx.doi.org/10.1038/npre.2008.2649.1 Fri, 12 Dec 2008 17:33:17 UTC Measurement & Prediction of Phase Behaviour of Carbon Dioxide Mixtures doi:10.1038/npre.2008.2649.1 2008-12-12 Esther Forte Nature Precedings 2008-12-12T17:33:17Z Poster Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2626.1 This is a fundamental study of trapping of non-wetting fluids in porous media. When injecting CO2 into an aquifer for carbon storage, the non-wetting phase (CO2) is trapped due to capillary forces. This process is investigated in the laboratory for analogue fluids. We then design an injection strategy to maximise CO2 storage capacity and efficiency on the field scale – incorporating experimental and pore scale modelling results. A streamline based simulator is modified for this purpose. http://dx.doi.org/10.1038/npre.2008.2626.1 Fri, 12 Dec 2008 16:39:27 UTC Carbon Storage: Integrating Experiments & Modelling to Quantify Trapping Capacity & Efficiency in the Subsurface doi:10.1038/npre.2008.2626.1 2008-12-12 Christopher H. Pentland Nature Precedings 2008-12-12T16:39:27Z Poster Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2638.1 The reduction in CO2 emissions from anthropogenic sources has become a topic of widespread interest over the past number of years. As the power generation sector is by far the largest stationary-point-source of CO2, being responsible for approximately 35% of total global CO2 emissions1 this question has special relevance for this industry. As the inclusion of carbon capture facilities incurs a significant energy penalty on the efficiency coal-fired power-stations, there is a strong requirement for the improvement of these systems in terms of the minimisation of operation and maintenance costs, capital costs and the maximisation of efficiency and flexibility. This last issue has relevance for start-up times and ramp-rates. Post-combustion capture methods based on the chemisorption of CO2 in aqueous amine solutions are among the most mature and accepted technologies for CO2 capture from power plants2. However, amines are complex, associating solvents requiring a sophisticated thermodynamic model, capable of modelling the hydrogen bonding interactions that occur in these systems. One such model is provided by the statistical associating fluid theory (SAFT3). This is a molecular approach, specifically suited to hydrogen-bonding, chain-like fluids. In this contribution we use the SAFT approach for potentials of variable range (SAFT-VR4) to model the thermodynamics and phase equilibria of a number of amines including ammonia and monoethanolamine. The molecules are modelled as homonuclear chains of tangentially bonded square-well segments of variable range, and a number of short-ranged off-centre attractive square-well sites are used to mediate the anisotropic effects due to association in the fluids. We also determine values of the binary parameters for mixtures and then use these parameters to predict the phase equilibria of amine+water, amine+carbon dioxide as well as water+carbon dioxide mixtures. We then consider the phase equilibria of the ternary mixtures of amine+water+carbon dioxide and finally that of quaternary mixtures of amine+water+carbon dioxide+nitrogen. A good quantitative understanding of the phase behaviour of these quaternary mixtures is essential for accurate modelling of absorption processes for carbon dioxide capture. 1. Steeneveldt, R., Berger, B. & Torp, T.A., ChERD, 84(A9): 739-763, 20062. Rao, A.B.; Rubin, E.S., 2002. A Technical, Economic, and Environmental Assessment of Amine-Based CO2 Capture Technology for Power Plant Greenhouse Gas Control. Environ. Sci. Technol. 36, 4467-44753. Chapman, W.G., Gubbins, K.E., Jackson, G. & Radosz, M., Ind. Eng. Chem. Res., 1990. 29, 1709-17213. Gil-Villegas, A., Galindo, A., Whitehead, P. J., Mills, S. J. & Jackson, G., J. Chem. Phys. 106 (10), 8 March 1997 http://dx.doi.org/10.1038/npre.2008.2638.1 Thu, 11 Dec 2008 22:58:33 UTC Advanced thermodynamic and processing modelling integration for amine scrubbing in post-combustion CO2 capture doi:10.1038/npre.2008.2638.1 2008-12-11 Niall Mac Dowell Nature Precedings 2008-12-11T22:58:33Z Presentation Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2640.1 In recent years, the debate over the most effective means to stabilize greenhouse gas concentrations in the atmosphere has endorsed multiple approaches and a variety of technologies. Assuring secure storage of anthropogenic carbon dioxide is one of our most pressing global scientific challenges that may contribute to achieving a stable solution over the next several decades. Geological sequestration by injection into deep-sea basalt formations provides unique and significant advantages over other potential storage options, including: (a) vast reservoir capacities with high porosity and permeability, sufficient to accommodate centuries-long U.S. production of fossil fuel CO2 at locations within a few hundreds of kilometers of populated areas; (b) chemical reactivity of CO2 with basalt and in situ fluids to produce stable, non-toxic carbonates; and (c) significant risk reduction for post-injection leakage by geological, gravitational, and mineral trapping mechanisms. We compare independent trapping mechanisms available in deep-sea basalts to those in saline aquifers, which have also been proposed as potential storage environments for anthropogenic carbon dioxide. We suggest that deep-sea basalts offer significant advantages over saline aquifers, in terms of reduced risk of post-injection leakage and storage capacity. Using a global site assessment strategy to highlight the most secure oceanic basalt sites that provide all trapping mechanisms, we initially identify potential target regions that occur in deep-sea basalt and calculate the potential injection volume for each. The largest volumes and most secure basalt sites occur in regions adjacent to intermediate- to fast-spreading seismic ridges as well as deep aseismic ridges. We then use site-specific criteria, such as abundance of ODP and IODP drill sites with basement penetration, permeability and/or porosity data, to refine volume calculations and to prioritize these target regions as promising locations to securely accommodate carbon dioxide injection. Pilot injection studies in deep-sea basalts are necessary to establish the viability of these reservoirs for future CO2 sequestration. We suggest that basaltic crust at deep ocean sites offers vast capacity and potential for permanent sequestration of carbon dioxide to mitigate atmospheric build-up of this greenhouse gas. http://dx.doi.org/10.1038/npre.2008.2640.1 Thu, 11 Dec 2008 22:57:54 UTC A global assessment of deep-sea basalt sites for carbon sequestration doi:10.1038/npre.2008.2640.1 2008-12-11 Angela L. Slagle Nature Precedings 2008-12-11T22:57:54Z Poster Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2633.1 An important trapping mechanism associated with the geosequestration of CO2 is that of dissolution into the formation water. Although supercritical CO2 is significantly less dense than water, experimental data reported in the literature show that the density of an aqueous solution of CO2 could be slightly greater. Under normal situations, the transfer of gas to solution is largely controlled by the relatively slow process of molecular diffusion. However, the presence of variable densities can trigger off gravity instabilities leading to much larger-scale convection processes. Such processes can potentially enhance rates of dissolution by an order of magnitude. Consequently there is a need for future performance assessment models to incorporate buoyancy driven convection (BDC). A major issue associated with BDC models is that of grid convergence when benchmarking to the Elder problem. The Elder problem originates from a heat convection experiment whereby a rectangular Hele-Shaw cell was heated over the central half of its base. A quarter of the way through the experiment, Elder (1967) observed six plumes, with four narrow plumes in the center and two larger plumes at the edges. As the experiment progressed, only four plumes remained. The issue is that depending on the grid resolution used when seeking to model this problem, modelers have found that different schemes yield steady states with either one, two or three plumes. The aim of this paper is to clarify and circumvent the issue of multiple steady state solutions in the Elder problem using a pseudospectral method. http://dx.doi.org/10.1038/npre.2008.2633.1 Wed, 10 Dec 2008 22:19:38 UTC Improving the worthiness of the Elder problem as a benchmark for buoyancy driven convection models doi:10.1038/npre.2008.2633.1 2008-12-11 Simon A. Mathias Nature Precedings 2008-12-10T22:19:38Z Presentation Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2634.1 If geo-sequestration of CO2 is to be employed as a key emissions reduction method in the global effort to mitigate climate change, simple yet robust screening of the risks of disposal in brine aquifers will be needed. There has been significant development of simple analytical and semi-analytical techniques to support screening analysis and performance assessment for potential carbon sequestration sites. These techniques have generally been used to estimate the size of CO2 plumes for the purpose of leakage rate estimation. A common assumption has been that both the fluids and the geological formation are incompressible. Consequently, calculation of pressure distribution requires the specification of an arbitrary radius of influence. In this talk, a new similarity solution is derived using the method of matched asymptotic expansions. By allowing for slight compressibility in the fluids and formation, the solution improves on previous work by not requiring the specification of an arbitrary radius of influence. A large-time approximation of the solution is then extended to account for non-Darcy inertial effects using the Forchheimer equation. Both solutions are verified by comparison with finite difference solutions. The results show that inertial losses will often be comparable, and sometimes greater than, the viscous Darcy-like losses associated with the brine displacement, although this is strongly dependent on formation porosity and permeability. http://dx.doi.org/10.1038/npre.2008.2634.1 Wed, 10 Dec 2008 22:18:54 UTC Pressure buildup during CO2 injection in brine aquifers using the Forchheimer equation doi:10.1038/npre.2008.2634.1 2008-12-10 Simon A. Mathias Nature Precedings 2008-12-10T22:18:54Z Presentation Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2630.1 A simple method of CO2 capture is by using the calcium looping cycle. The calcium looping cycle uses CaCO3 as a CO2 carrier, via the reversible reaction CaO(s) + CO2(g) = CaCO3(s), to extract CO2 from the exhaust stream and provide a pure stream of CO2 suitable for sequestration. A problem associated with the technology is that the capacity of the sorbent to absorb CO2 reduces significantly with the number of cycles of carbonation and calcination. The energy penalty of the cycle is considerably increased by cycling unreacted sorbent: hydration of unreactive sorbent has emerged as a promising strategy of reducing this penalty by regenerating the reactivity of exhausted sorbent.A small atmospheric pressure fluidised bed reactor has been built and tested, that allows repeated cycling between two temperatures up to 1000 °C. Work presented here focuses on the effects of variation of the calcination temperature before hydration. Hydration has been found to more than double the reactivity of a spent sorbent cycled under the mildest conditions studied (calcination temperature of 840 °C). However, as calcination temperature is increased the observed reactivation decreases until little reactivation is observed for the sorbent cycled at 950 °C. The primary reason for this appears to be a substantial increase in friability of particles, with reactivity normalised for mass losses appearing similar independent of cycling temperature. http://dx.doi.org/10.1038/npre.2008.2630.1 Wed, 10 Dec 2008 17:54:55 UTC Reactivation of Limestone-Derived Sorbents using Hydration: Preliminary Results From a Fluidised Bed doi:10.1038/npre.2008.2630.1 2008-12-10 John Blamey Nature Precedings 2008-12-10T17:54:55Z Presentation Chemistry Earth & Environment http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2628.1 Carbon capture and storage (CCS) – the collection of carbon dioxide (CO2) from industrial sources and its injection underground – is an important technology to reduce CO2 emissions to the atmosphere, mitigating climate change. The North Sea, with mature hydrocarbon fields and saline aquifers offers an attractive storage location for CO2 produced by the UK’s gas and coal-fired power plants. The principal concern with CCS is to ensure that the CO2 does not leak into the oceans or atmosphere over hundreds or thousands of years. We propose a storage strategy where CO2 and brine are injected together followed by brine injection alone. We predict that using this technique around 95% of the CO2 can be rendered immobile in pore-scale (10s micron) droplets in the porous rock. Over thousands to billions of years the CO2 may dissolve or precipitate as carbonate, but it will not migrate upwards and so is effectively sequestered. This design is demonstrated through numerical simulation of field-scale flow through a North Sea aquifer coupled to an experimentally-based model of small-scale trapping. The CO2 is trapped during the decades-long lifetime of the injection phase, avoiding the need for extensive monitoring for centuries. The method does not rely on impermeable cap rock to contain the CO2; this is only a secondary containment for the small amount of remaining mobile gas. Furthermore, the reduced mobility ratio between injected and displaced fluids leads to a more uniform sweep of the aquifer leading a larger storage capacity than injecting CO2 alone. http://dx.doi.org/10.1038/npre.2008.2628.1 Wed, 10 Dec 2008 14:28:57 UTC Design of carbon dioxide storage doi:10.1038/npre.2008.2628.1 2008-12-10 Martin J. Blunt Nature Precedings 2008-12-10T14:28:57Z Presentation Earth & Environment http://creativecommons.org/licenses/by/3.0/