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AbstractThis paper assesses how parameter uncertainties in the model for rise velocity of CO2 droplets in the ocean cause uncertainties in their rise and dissolution in marine waters. The parameter uncertainties in the rise velocity for both hydrate coated and hydrate free droplets are estimated from experiment data. Thereafter the rise velocity is coupled with a mass transfer model to simulate the fate of dissolution of a single droplet.The assessment shows that parameter uncertainties are highest for large droplets. However, it is also shown that in some circumstances varying the temperature gives significant change in rise distance of droplets.

At the Ketzin pilot site, Germany, electrical resistivity tomography (ERT) is a substantial component in a multi-disciplinary monitoring concept established in order to image CO2 injected in a saline aquifer. Since more than five years, crosshole ERT data sets have repeatedly been collected using a borehole electrode array acting as a permanent reservoir monitoring tool. This contribution summarizes the aspects being essential for a successful deployment and operation of such a downhole installation. It is shown that the presented installation can facilitate stable and reliable data collection at least throughout the investigated five- year period of ongoing CO2 injection. Based on the experiences being gained so far, it is concluded that a properly calibrated and integrated downhole ERT system allows for mapping of quantitative CO2 saturation estimates in the subsurface. 12th International Conference on Greenhouse Gas Control Technologies, GHGT-12 Energy Procedia, 63 ISSN:1876-6102

AbstractThe gas diffusion layer (GDL) of the proton exchange membrane (PEM) fuel cell is a vital component in water management since humidification and water removal are both achieved through the GDL. Capillary action in the GDL porous structure enhances water removal from the cathode catalyst layer, and hence prevents flooding which blocks the pathways of the reactants to the activation sites. To improve the transport of water and reactants, GDL properties are varied by changing the geometry and the PTFE loading of the carbon fiber paper (CFP), both changing the internal wettability of the GDL. In essence, the wettability describes the interaction of water with the porous structures inside the GDL. The knowledge of the surface properties and pore structure is important to enhance water management in the cell. In this work, two ex-situ techniques are used to measure transport characteristics of GDLs, such as the internal wettability, pore size distribution and permeability. These measurements have been applied to different types of GDLs with different structures and PTFE loadings. The comparison between the results will determine the effect of material and treatment on the properties of GDLs which can provide basic insight into the two-phase flow in this porous layer.

This article was published open access in Energy Procedia on 23 October 2017, available at https://doi.org/10.1016/j.egypro.2017.09.532

AbstractThe Pembina Cardium CO2 Monitoring Project in central Alberta was built to assess the Cardium formation’s storage potential for CO2 and stimulate oil production. Three baseline trips and 28 monitoring trips were undertaken over a three year period from February 2005 to March 2008 to collect fluids and gas from eight producing wells. Chemical and isotope analyses were conducted on the fluid and gas samples to determine the changes in the geochemistry of the pilot area and to assess the fate of the injected CO2. It was found that within 67 days after commencement of CO2 injection, injection CO2 break-through occurred in four of the eight monitoring wells. Further, CO2 dissolution was observed in three of the four monitoring wells in this time frame and in one well, 12–12, both CO2 dissolution and calcite mineral dissolution were observed within 67 days of the onset of CO2 injection. Within 18 months siderite dissolution and calcite dissolution were observed in all four of these wells. In the remaining four wells, CO2 dissolution was observed, indicated by a slow decreased in pH from 7.5 to 7.2 with no significant change in total alkalinity or calcium concentration in the water. Inter-well communications were observed between wells 08–11 and 12–12 by means of residual “kill fluid” migration occurring from well 12–12 to well 08–11.

AbstractOptimisation of injection rates is an important design consideration for meeting operational objectives and ensuring long term geological storage of CO2 in saline aquifers. The optimal design should also take into account the uncertainties associated with the subsurface (e.g., petrophysical attribution and structural relationships). Detailed geological models along with different realisations for handling uncertainties increase the computational overheads, making the optimisation problem intractable. To circumvent this problem, upscaled models can be used to speed up the identification of optimal solutions. Nevertheless, a grid resolution, which does not compromise the accuracy of the optimisation in an upscaled model, must be carefully determined. The methodology described in this paper aims to address this requirement. In this study, a 3D geological model, comprising the main oil reservoirs of the Forties and Nelson hydrocarbon fields and the adjacent saline aquifer, was built to examine the use of coarse grid resolutions to design an optimal CO2 storage solution for this area within the UK Central North Sea. Simulation results for single objective optimisation show that an upscaled grid resolution can be identified which is a trade-off between accuracy and computational time. The outlined methodology is generic in nature and can be ported to other similar optimisation problems for CO2 storage.