31,753 research outputs found

    Prediction of water retention of soils from the humid tropics by the nonparametric k-nearest neighbor approach

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    Nonparametric approaches such as the k-nearest neighbor (k-NN) approach are considered attractive for pedotransfer modeling in hydrology; however, they have not been applied to predict water retention of highly weathered soils in the humid tropics. Therefore, the objectives of this study were: to apply the k-NN approach to predict soil water retention in a humid tropical region; to test its ability to predict soil water content at eight different matric potentials; to test the benefit of using more input attributes than most previous studies and their combinations; to discuss the importance of particular input attributes in the prediction of soil water retention at low, intermediate, and high matric potentials; and to compare this approach with two published tropical pedotransfer functions (PTFs) based on multiple linear regression (MLR). The overall estimation error ranges generated by the k-NN approach were statistically different but comparable to the two examined MLR PTFs. When the best combination of input variables (sand + silt + clay + bulk density + cation exchange capacity) was used, the overall error was remarkably low: 0.0360 to 0.0390 m(3) m(-3) in the dry and very wet ranges and 0.0490 to 0.0510 m(3) m(-3) in the intermediate range (i.e., -3 to -50 kPa) of the soil water retention curve. This k-NN variant can be considered as a competitive alternative to more classical, equation-based PTFs due to the accuracy of the water retention estimation and, as an added benefit, its flexibility to incorporate new data without the need to redevelop new equations. This is highly beneficial in developing countries where soil databases for agricultural planning are at present sparse, though slowly developing

    Integrated characterisation of mud-rich overburden sediment sequences using limited log and seismic data: Application to seal risk

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    Muds and mudstones are the most abundant sediments in sedimentary basins and can control fluid migration and pressure. In petroleum systems, they can also act as source, reservoir or seal rocks. More recently, the sealing properties of mudstones have been used for nuclear waste storage and geological CO2 sequestration. Despite the growing importance of mudstones, their geological modelling is poorly understood and clear quantitative studies are needed to address 3D lithology and flow properties distribution within these sediments. The key issues in this respect are the high degree of heterogeneity in mudstones and the alteration of lithology and flow properties with time and depth. In addition, there are often very limited field data (log and seismic), with lower quality within these sediments, which makes the common geostatistical modelling practices ineffective. In this study we assess/capture quantitatively the flow-important characteristics of heterogeneous mud-rich sequences based on limited conventional log and post-stack seismic data in a deep offshore West African case study. Additionally, we develop a practical technique of log-seismic integration at the cross-well scale to translate 3D seismic attributes into lithology probabilities. The final products are probabilistic multiattribute transforms at different resolutions which allow prediction of lithologies away from wells while keeping the important sub-seismic stratigraphic and structural flow features. As a key result, we introduced a seismically-driven risk attribute (so-called Seal Risk Factor "SRF") which showed robust correspondence to the lithologies within the seismic volume. High seismic SRFs were often a good approximation for volumes containing a higher percentage of coarser-grained and distorted sediments, and vice versa. We believe that this is the first attempt at quantitative, integrated characterisation of mud-rich overburden sediment sequences using log and seismic data. Its application on modern seismic surveys can save days of processing/mapping time and can reduce exploration risk by basing decisions on seal texture and lithology probabilities

    Comparative Analysis of Artificial Intelligence and Numerical Reservoir Simulation in Marcellus Shale Wells

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    This dissertation addresses the limitations of conventional numerical reservoir simulation techniques in the context of unconventional shale plays and proposes the use of data-driven artificial intelligence (AI) models as a promising alternative. Traditional methods, while providing valuable insights, often rely on simplifying assumptions and are constrained by time, resources, and data quality. The research leverages AI models to handle the complexities of shale behavior more effectively, facilitating accurate predictions and optimizations with less resource expenditure. Two specific methodologies are investigated for this purpose: traditional numerical reservoir simulations using Computer Modelling Group\u27s GEM reservoir simulation software, and an AI-based Shale Analytics approach using IMPROVEâ„¢ software from Intelligent Solutions, Inc. The investigation covers the impact of key parameters on production prediction, assumptions made, predictive accuracy, data requirements, workflow complexity, and time efficiency. By comparing these methods, the research aims to offer guidelines for incorporating AI models into reservoir simulation and identify areas for increased efficiency and accuracy. The study concludes by presenting recommendations to advance the field of reservoir simulation and encourage the adoption of innovative methodologies in the energy industry. The results are anticipated to considerably enhance reservoir simulation processes and optimize production strategies for unconventional shale plays

    Artificial Intelligence and Cognitive Computing

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    Artificial intelligence (AI) is a subject garnering increasing attention in both academia and the industry today. The understanding is that AI-enhanced methods and techniques create a variety of opportunities related to improving basic and advanced business functions, including production processes, logistics, financial management and others. As this collection demonstrates, AI-enhanced tools and methods tend to offer more precise results in the fields of engineering, financial accounting, tourism, air-pollution management and many more. The objective of this collection is to bring these topics together to offer the reader a useful primer on how AI-enhanced tools and applications can be of use in today’s world. In the context of the frequently fearful, skeptical and emotion-laden debates on AI and its value added, this volume promotes a positive perspective on AI and its impact on society. AI is a part of a broader ecosystem of sophisticated tools, techniques and technologies, and therefore, it is not immune to developments in that ecosystem. It is thus imperative that inter- and multidisciplinary research on AI and its ecosystem is encouraged. This collection contributes to that
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