The Experts below are selected from a list of 17232 Experts worldwide ranked by ideXlab platform
Jo Plested - One of the best experts on this subject based on the ideXlab platform.
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using evolutionary algorithms for hyperparameter tuning and network reduction techniques to classify Core Porosity classes based on petrographical descriptions
International Conference on Neural Information Processing, 2019Co-Authors: Tommy Liu, Jo PlestedAbstract:Classifying the Porosity of sedimentary information is an important field of study with applications to tasks such as oil reservoir characterisation. Classifying Porosity into groups based on Petrographical characteristics has been attempted in the past using: expert systems, supervised clustering techniques and neural networks. In this paper, we expand upon the usage of neural networks for this classification task by applying Evolutionary Algorithms to determine optimal parameters. Despite recent advances in techniques to select hyperparameters it is still difficult to determine the optimal parameters for a given dataset. We further apply network reduction techniques to further improve classification accuracy. We produce results similar to the work done by Gedeon et al. [1] on this dataset.
Bruce J Balcom - One of the best experts on this subject based on the ideXlab platform.
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spatially resolved measurement of rock Core Porosity
Journal of Magnetic Resonance, 2006Co-Authors: F Marica, Quan Chen, Andrea Hamilton, Christopher Hall, Bruce J BalcomAbstract:Density weighted, centric scan, Conical SPRITE MRI techniques are applied in the current work for local Porosity measurements in fluid saturated porous media. The methodology is tested on a series of sandstone Core samples. These samples vary in both Porosity and degree of local heterogeneity due to bedding plane structure. The MRI Porosity measurement is in good agreement with traditional gravimetric measurements of Porosity. Spatially resolved Porosity measurements reveal significant Porosity variation in some samples. This novel MRI technique should have applications to the characterization of local Porosity in a wide variety of porous media.
Xavier Choi - One of the best experts on this subject based on the ideXlab platform.
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quantitative analysis of micro structural changes in a bituminous coal after exposure to supercritical co2 and water
Nutrition and Cancer, 2019Co-Authors: Guanglei Zhang, P G Ranjith, M S A Perera, Xavier ChoiAbstract:High-volatile bituminous coal samples were reacted in deionized water with supercritical CO2 (ScCO2–water) under simulated in situ pressure and temperature conditions (8 MPa and 40 °C) in unconfined stress state for 14 days, in order to characterize potential CO2–water–coal reactions. Micro-structural changes were identified pre- and post-experiment using X-ray powder diffraction (XRD) analysis for powdered coal (mineralogical changes), optical microscopy and scanning electron microscopy (SEM) for polished thin sections (surface feature changes) and micro-CT scanning for a small Core (Porosity and permeability changes). XRD analysis revealed that carbonic acid leaches out mineral matters in coal, including carbonates (calcite) and silicate minerals (albite, illite and kaolinite). Optical microscopy, SEM and CT images confirmed that the interaction of coal with ScCO2–water causes an abundance of micro-cracks to open or propagate in unconfined coal samples. Most micro-cracks preferably propagated along maceral–mineral and maceral–maceral interfaces, which demonstrates that the micro-cracking was caused by differential swelling of different coal lithotypes. Wormhole formation was observed in coal caused by mineral dissolution and hydrocarbon mobilization, which significantly increases coal Porosity compared with swelling-induced cracking. 3-D pore network models extracted from CT images show that ScCO2–water treatment enlarges the pore and throat size, increases the numbers of pores and throats and improves pore network connectivity. Overall, CO2–water–coal interactions under unconfined conditions enhance coal Porosity, connectivity and permeability, which can be attributed to the combined effect of micro-cracking, mineral dissolution and hydrocarbon mobilization.
Sevket Durucan - One of the best experts on this subject based on the ideXlab platform.
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supercritical co2 Core flooding and imbibition in tako sandstone influence of sub Core scale heterogeneity
International Journal of Greenhouse Gas Control, 2011Co-Authors: Sevket DurucanAbstract:Abstract This paper presents a numerical simulation study of a full CO 2 Core flooding and imbibition cycle performed on a heterogeneous Tako sandstone Core (measured 14.5 cm long and 3.68 cm in diameter). During the test, supercritical CO 2 (at 10 MPa and 40 °C) and CO 2 -saturated brine was injected into one end of the horizontal Core and a X-ray CT scanner (with a resolution of 0.35 mm × 0.35 mm) was employed to monitor and record changes in the fluid saturations, which enabled 3D mapping of the saturation profiles throughout the Core during the course of Core flooding test. The CO 2 flooding test demonstrated that (1) sub-Core Porosity heterogeneity had a marked impact on the CO 2 migration pattern within the Tako sandstone Core at low injection rates (∼0.1 cm 3 /min); (2) the influence of the Porosity heterogeneity on the mean CO 2 saturation profiles along the Core became gradually diminished as the injection rate was increased in steps to 3 cm 3 /min. The numerical simulation results have shown that the immiscible displacement processes in the heterogeneous Tako Core could not be adequately described by using a single capillary pressure curve in a 1D model of the Core. This was found to be the case even when a 3D model (5 × 5 × 24) was used, where the Porosity/permeability heterogeneity across the cross-sections, as well as along the Core, was taken into account. Furthermore, the apparent correlation between the CO 2 saturation and the Porosity (mean) profiles during the CO 2 flooding could largely be accounted for by employing a Leverett J-function type scaling factor, which reflects the influence of Porosity/permeability heterogeneity on the capillary pressure.
Hui Gao - One of the best experts on this subject based on the ideXlab platform.
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determination of movable fluid percentage and movable fluid Porosity in ultra low permeability sandstone using nuclear magnetic resonance nmr technique
Journal of Petroleum Science and Engineering, 2015Co-Authors: Hui GaoAbstract:Abstract In ultra-low permeability reservoirs, the movable fluid parameters (including movable fluid percentage and movable fluid Porosity) are very important measures in that they can provide realistic assessment of the amount of fluid that can flow in the porous media. In this study, the movable fluid percentage and movable fluid Porosity of 264 Core samples obtained from the Yanchang group of Ordos basin (China) are determined using the nuclear magnetic resonance (NMR) technique. The test results show that the T2 distributions present five typical patterns: bimodal distribution with higher left peak and lower right peak (occupying 26.52%), bimodal distribution with lower left peak but higher right peak (occupying 37.50%), bimodal distribution with similar amplitudes of the two peaks (occupying 35.23%), unimodel distribution (occupying 0.38%), and triple-peak distribution (occupying 0.38%). The pore throat radius exists mainly over the ranges of 1–10 μm and 10–100 μm, while the T2 cutoff value is found to mainly distribute between 5.34 and 20.00 ms. The average movable fluid percentage and average movable fluid Porosity of the 264 Core samples are 48.35% and 5.43%, respectively. The movable fluid percentage shows almost no correlation with Porosity; it varies dramatically when the permeability is low and tends to converge to a higher value with an increase in permeability. The movable fluid Porosity exhibits a relatively good correlation with Core Porosity as well as Core permeability. There is obvious difference between the movable fluid parameters and physical property in different reservoirs because of the difference in wettability, microcrack and pore structure. The movable fluid parameters are comprehensive reflection of micro-characteristics of ultra-low permeability reservoir.