High-dimensional geostatistical history matching     

João Carneiro  Leonardo Azevedo  Maria Pereira 《Computational Geosciences》2018,22(2):607-622

Hydrocarbon reservoir modelling and characterisation is a challenging subject within the oil and gas industry due to the lack of well data and the natural heterogeneities of the Earth’s subsurface. Integrating historical production data into the geo-modelling workflow, commonly designated by history matching, allows better reservoir characterisation and the possibility of predicting the reservoir behaviour. We present herein a geostatistical-based multi-objective history matching methodology. It starts with the generation of an initial ensemble of the subsurface petrophysical property of interest through stochastic sequential simulation. Each model is then ranked according the match between its dynamic response, after fluid flow simulation, and the observed available historical production data. This enables building regionalised Pareto fronts and the definition of a large ensemble of optimal subsurface Earth models that fit all the observed production data without compromising the exploration of the uncertainty space. The proposed geostatistical multi-objective history matching technique is successfully implemented in a benchmark synthetic reservoir dataset, the PUNQ-S3, where 12 objectives are targeted.  相似文献   

Gravimetric and magnetic fabric study of the Sintra Igneous complex: laccolith-plug emplacement in the Western Iberian passive margin     

Terrinha  Pedro  Pueyo  Emilio L.  Aranguren  Aitor  Kullberg  José Carlos  Kullberg  Maria Carla  Casas-Sainz  Antonio  Azevedo  Maria do Rosário 《International Journal of Earth Sciences》2018,107(5):1807-1833

International Journal of Earth Sciences - The geometry and emplacement of the ~ 96 km2, Late Cretaceous Sintra Igneous complex (SIC, ca. 80 Ma) into the West Iberian passive...  相似文献   

Wind-Driven Dissolved Organic Matter Dynamics in a Chesapeake Bay Tidal Marsh-Estuary System     

J. Blake Clark  Wen Long  Maria Tzortziou  Patrick J. Neale  Raleigh R. Hood 《Estuaries and Coasts》2018,41(3):708-723

Controls on organic matter cycling across the tidal wetland-estuary interface have proved elusive, but high-resolution observations coupled with process-based modeling can be a powerful methodology to address shortcomings in either methodology alone. In this study, detailed observations and three-dimensional hydrodynamic modeling are used to examine biogeochemical exchanges in the marsh-estuary system of the Rhode River, MD, USA. Analysis of observations near the marsh in 2015 reveals a strong relationship between marsh creek salinity and dissolved organic matter fluorescence (fDOM), with wind velocity indirectly driving large amplitude variation of both salinity and fDOM at certain times of the year. Three-dimensional model results from the Finite Volume Community Ocean Model implemented for the wetland system with a new marsh grass drag module are consistent with observations, simulating sub-tidal variability of marsh creek salinity. The model results exhibit an interaction between wind-driven variation in surface elevation and flow velocity at the marsh creek, with northerly winds driving increased freshwater signal and discharge out of the modeled wetland during precipitation events. Wind setup of a water surface elevation gradient axially along the estuary drives the modeled local sub-tidal flow and thus salinity variability. On sub-tidal time scales (>36 h, <1 week), wind is important in mediating dissolved organic matter releases from the Kirkpatrick Marsh into the Rhode River.  相似文献   

Three-dimensional numerical and analytical study of horizontal group of square anchor plates in sand     

Hicham Mokhbi  Mekki Mellas  Abdelhak Mabrouki  Jean-Michel Pereira 《Acta Geotechnica》2018,13(1):159-174

In this paper, numerical and analytical methods are used to evaluate the ultimate pullout capacity of a group of square anchor plates in row or square configurations, installed horizontally in dense sand. The elasto-plastic numerical study of square anchor plates is carried out using three-dimensional finite element analysis. The soil is modeled by an elasto-plastic model with a Mohr–Coulomb yield criterion. An analytical method based on a simplified three-dimensional failure mechanism is developed in this study. The interference effect is evaluated by group efficiency η, defined as the ratio of the ultimate pullout capacity of group of N anchor plates to that of a single isolated plate multiplied by number of plates. The variation of the group efficiency η was computed with respect to change in the spacing between plates. Results of the analyses show that the spacing between the plates, the internal friction angle of soil and the installation depth are the most important parameters influencing the group efficiency. New equations are developed in this study to evaluate the group efficiency of square anchor plates embedded horizontally in sand at shallow depth (H = 4B). The results obtained by numerical and analytical solutions are in excellent agreement.  相似文献   

Impact of drilling mud on chemistry and microbiology of an Upper Triassic groundwater after drilling and testing an exploration well for aquifer thermal energy storage in Berlin (Germany)     

Simona Regenspurg  Mashal Alawi  Guido Blöcher  Maria Börger  Stefan Kranz  Ben Norden  Ali Saadat  Traugott Scheytt  Lioba Virchow  Andrea Vieth-Hillebrand 《Environmental Earth Sciences》2018,77(13):516

After completion of an exploration well, sandstones of the Exter Formation were hydraulically tested to determine the hydraulic properties and to evaluate chemical and microbial processes caused by drilling and water production. The aim was to determine the suitability of the formation as a reservoir for aquifer thermal energy storage. The tests revealed a hydraulic conductivity of 1–2 E-5 m/s of the reservoir, resulting in a productivity index of 0.6–1 m³/h/bar. A hydraulic connection of the Exter Formation to the overlaying, artesian “Rupelbasissand” cannot be excluded. Water samples were collected for chemical and microbiological analyses. The water was similarly composed as sea water with a maximum salinity of 24.9 g/L, dominated by NaCl (15.6 g/L Cl and 7.8 g/L Na). Until the end of the tests, the water was affected by drilling mud as indicated by the high pH (8.9) and high bicarbonate concentration (359 mg/L) that both resulted from the impact of sodium carbonate (Na₂CO₃) additives. The high amount of dissolved organic matter (>?58 mg/L) and its molecular-weight distribution pattern indicated that residues of cellulose, an ingredient of the drilling mud, were still present at the end of the tests. Clear evidence of this contamination gave the measured uranine that was added as a tracer into the drilling mud. During fluid production, the microbial community structure and abundance changed and correlated with the content of drilling mud. Eight taxa of sulfate-reducing bacteria, key organisms in processes like bio-corrosion and bio-clogging, were identified. It can be assumed that their activity will be affected during usage of the reservoir.  相似文献   

Ecotoxicological evaluation of dredged sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro State,Brazil) using bioassays with earthworms and collembolans     

Mariana Vezzone  Ricardo Cesar  Helena Polivanov  Aline Serrano  Danielle Siqueira  Leticia Abreu  Miriam Bianchi  Maria Elizabeth Correia  Zuleica Castilhos  Tácio de Campos 《Environmental Earth Sciences》2018,77(21):743

The toxicity and metal bioavailability were studied in dredged sediments from Rodrigo de Freitas Lagoon (Rio de Janeiro, RJ, Brazil) using acute and avoidance tests with Eisenia andrei, and reproduction tests with Folsomia candida. The sediment was mixed with an artificial soil, and two natural soils (ferralsol and chernosol—representative Brazilian tropical soils) to obtain the following doses: 1, 3, 6, 12, 18, 24 and 30%. Total metal concentrations were determined in the sediment to support the interpretation of ecotoxicological data. Metal concentrations in the mixtures were in agreement with the threshold limits established by Brazilian law. However, significant avoidance responses were found on doses ≥?3% and were the most sensitive endpoint. Earthworm mortality found in artificial soil mixtures (LC50?=?3.9) suggests higher toxicity levels than those obtained in ferralsol (LC50?=?7.6%) and chernosol (11.0%) treatments. Earthworm mortality, avoidance responses and collembolan reproduction levels found in ferralsol mixtures (LC50?=?9.2; avoidance EC50?=?2.3%; reproduction EC50?=?2.8%) were higher compared to chernosol treatments (LC50?=?11.0%; avoidance EC50?=?4.3%; reproduction EC50?=?4.9%). The reduction of toxicity levels in chernosol mixtures is probably due to the abundance of expansive clay minerals in chernosols with capacity of adsorbing metals and other xenobiotic substances from soil pore water, decreasing metal bioavailability. Finally, threshold limits defined by Brazilian legislation for soil quality and land disposal of dredged sediments are not sufficient to prevent noxious effects on soil fauna and should be complemented with a preliminary ecotoxicological evaluation.  相似文献   

Spectral data source effect on crop state estimation by vegetation indices     

Maria Polinova  Thomas Jarmer  Anna Brook 《Environmental Earth Sciences》2018,77(22):752

Spectral vegetation indices (VIs) are a well-known and widely used method for crop state estimation. The ability to monitor crop state by such indices is an important tool for agricultural management. Even though differences in imagery and point-based spectroscopy are obvious, their impact on crop state estimation by VIs is not well-studied. The aim of this study was to assess the performance level of the selected VIs calculated from spaceborne multispectral imagery and point-based field spectroscopy in application to crop state estimation. For this purpose, irrigated chickpea field was monitored by RapidEye satellite mission and additional measurements by field spectrometer were obtained. Estimated VIs average and coefficient of variation from each observation were compared with physical crop measurements: leaf water content, LAI and chlorophyll level. The results indicate that indices calculated from spaceborne spectral images regardless of the claimed response commonly react on phenology of the irrigated chickpea. This feature makes spaceborne spectral imagery an appropriate data source for monitoring crop development, crop water needs and yield prediction. VIs calculated from field spectrometer were sensitive for estimating pigment concentration and photosynthesis rate. Yet, a hypersensitivity of field spectral measures might lead to a very high variability (up to 69%) of the calculated values. Consequently, the high spatial variability of field spectral measurements depreciates the estimation agricultural field state by average mean only. Nevertheless, the spatial variability might have certain behavior trend, e.g., a significant increase in the active growth or stress and can be an independent feature for field state assessment.  相似文献   

Hydrologic models coupled with 2D hydrodynamic model for high-resolution urban flood simulation     

de Arruda Gomes  Mayara Maria  de Melo Verçosa  Lívia Fragoso  Cirilo  José Almir 《Natural Hazards》2021,108(3):3121-3157

Natural Hazards - Floods are the most frequent natural disaster and pose a very challenging threat to many cities worldwide. Understanding the flood dynamic is essential for developing strategies...  相似文献   

Methodological challenges to confirmatory latent variable models of social vulnerability     

Goodman  Zachary T.  Stamatis  Caitlin A.  Stoler  Justin  Emrich  Christopher T.  Llabre  Maria M. 《Natural Hazards》2021,106(3):2731-2749

Natural Hazards - Socially vulnerable communities experience disproportionately negative outcomes following natural disasters and underscoring a need for well-validated measures to identify those...  相似文献   

The P-y Response of Laterally Loaded Flexible Piles in Residual Soil     

Consoli  Nilo Cesar  Reginato  Naiara da Costa  Lopes Júnior  Luizmar da Silva  Rocha  Marcelo Maia  Faro  Vítor Pereira  Born  Ricardo Bergan 《Geotechnical and Geological Engineering》2021,39(6):4295-4313

This paper describes the main features related to lateral displacements with depth after successive lateral loading–unloading cycles applied to the top of reinforced-concrete flexible bored piles embedded in naturally bonded residual soil. The bored piles under study have a cylindrical shape, with 0.40-m in diameter and 8.0-m in length. Both bored piles types (P1 and P2) include an embedded steel pipe section in their center as longitudinal steel reinforcements: pile type P1 has another 16 steel rods as steel reinforcement to concrete while pile type P2 has no further steel reinforcement. Pile type P1 has three times as much stiffness (EI) and four and a half times the plastic moment (M_y) than pile type P2. A similar load–displacement performance was observed at initial loads as for small displacements of both piles. At this initial loading stage, the response of the reinforced concrete piles is a function of the soil characteristics and of a linear elastic pile deformation. During this stage, piles can even be understood as probes for evaluating soil reactions. For larger horizontal displacements, after the concrete section starts undergoing large deformations, approaching the ultimate bending moment, pile behavior and consequently the load–displacement relation starts to diverge for both piles. For pile P1 the values of relevant lateral displacements are extended to about 2.5-m in depth, while for pile P2 lateral displacements are mostly constrained to about 2.0-m in depth. Measurements of horizontal displacements of pile P1 against depth recorded with a slope indicator show that, after unloading, lateral loads at distinct stages (small and near failure loads), exhibits a much higher elastic phase of the system response. An analytical fitting model of soil reaction is proposed based on the measured displacements from slope indicator. The integration of a continuous model proposed for the soil reaction agrees fairly well with the measured displacements up to moments close to plastic limit. Results of load–displacement show that the stiffer pile (P1) was able to mobilize twice as much lateral load compared to pile P2 for a service limit displacement of about 20 mm. The paper shows results that enable the isolation of the structural variable through real scale pile load tests, thus granting understanding of its importance and enabling its quantitative visualization in examples of piles embedded in residual soil sites.

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