scholarly journals Marlim R3D: a realistic model for CSEM simulations - phase I: model building

2017 ◽  
Vol 47 (4) ◽  
pp. 633-644 ◽  
Author(s):  
Bruno Rodrigues Carvalho ◽  
Paulo Tarso Luiz Menezes
Keyword(s):  
Model Building ◽  
Reference Model ◽  
Sedimentary Basins ◽  
Realistic Model ◽  
Complex Model ◽  
Well Log ◽  
Recent Past ◽  
Complementary Information ◽  
Geoelectric Model ◽  
Calibration Time

ABSTRACT: The marine controlled-source electromagnetic (CSEM) method provides complementary information to seismic imaging in the exploration of sedimentary basins. The CSEM is mainly used for reservoir scanning and appraisal. The CSEM interpretation workflow is heavily based on inversion and forward - modeling for hypothesis testing. Until the recent past, the effectiveness of a given workflow was achieved after the drilling results, as there wasn’t any geological complex model available to serve as a benchmark. In the present paper, we describe the workflow to build up Marlim R3D, a realistic and complex geoelectric model. Marlim R3D aims to be a reference model of turbidite reservoirs of the Brazilian continental margin. Our model is based on seismic interpretation and constrained by the input of available well-log information. The workflow used is composed of seven steps: seismic and well-log dataset loading, well-tie, Vp cube construction, Vp resistivity calibration, time-depth conversion, resistivity cube construction, and quality-control check. As a result, we obtained an interpreted dataset composed by main stratigraphic horizons, pseudo-well logs, and the resistivity cubes. These elements were made freely available for research or commercial use, under the Creative Common License, at the Zenodo platform.

scholarly journals MEDIATION OF SUPERSYMMETRY BREAKING IN EXTRA DIMENSIONS

2005 ◽  
Vol 20 (05) ◽  
pp. 297-312 ◽  
Author(s):  
CLAUDIO A. SCRUCCA
Keyword(s):  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Extra Dimensions ◽  
Model Building ◽  
Realistic Model ◽  
Effective Field ◽  
Theory Approach ◽  
Classical Level ◽  
Gravitational Effects ◽  
Gravitational Fields

We review the mechanisms of supersymmetry breaking mediation that occur in sequestered models, where the visible and the hidden sectors are separated by an extra dimension and communicate only via gravitational interactions. By locality, soft breaking terms are forbidden at the classical level and reliably computable within an effective field theory approach at the quantum level. We present a self-contained discussion of these radiative gravitational effects and the resulting pattern of soft masses, and give an overview of realistic model building based on this setup. We consider both flat and warped extra dimensions, as well as the possibility that there be localized kinetic terms for the gravitational fields.

A 3D Optimized Frequency–Wavenumber (FK), Time–Space Optimized Symplectic (TSOS) Hybrid Method for Teleseismic Wave Modeling

2021 ◽  
Author(s):  
Weijuan Meng ◽  
Dinghui Yang ◽  
Xingpeng Dong ◽  
Jian Ma
Keyword(s):  
High Resolution ◽  
Seismic Wave ◽  
Hybrid Method ◽  
High Efficiency ◽  
Reference Model ◽  
3D Models ◽  
Realistic Model ◽  
High Accuracy ◽  
Memory Requirement ◽  
Time Space

ABSTRACT Although teleseismic waveform tomography can provide high-resolution images of the deep mantle, it is still unrealistic to numerically simulate the whole domain of seismic wave propagation due to the huge amount of computation. In this article, we develop a new three-dimensional hybrid method to address this issue, which couples the modified frequency–wavenumber (FK) method with the 3D time–space optimized symplectic (TSOS) method. First, the FK method, which is used to calculate the semianalytical incident wavefields in the layered reference model, is modified to compute the wavefields efficiently with a significantly low-memory requirement. Second, 3D TSOS method is developed to model the seismic wave propagating in the local 3D heterogeneous domain. The low memory requirement of the modified FK method and the high accuracy of the TSOS method make it feasible to obtain highly accurate synthetic seismograms efficiently. A crust–upper mantle model for P-, SV-, and SH-wave incidences is calculated to benchmark the accuracy and efficiency of the 3D optimized FK-TSOS method. Numerical experiments for 3D models with heterogeneities, undulated discontinuous interfaces, and realistic model in eastern Tibet, illustrate the capability of hybrid method to accurately capture the scattered waves caused by heterogeneities in 3D medium. The 3D optimized FK-TSOS method developed shows low-memory requirement, high accuracy, and high efficiency, which makes it be a promising forward method to further apply to high-resolution mantle structure images beneath seismic array.

Marlim R3D: A realistic model for controlled-source electromagnetic simulations — Phase 2: The controlled-source electromagnetic data set

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. E293-E299
Author(s):  
Jorlivan L. Correa ◽  
Paulo T. L. Menezes
Keyword(s):  
A Priori ◽  
Synthetic Data ◽  
Realistic Model ◽  
Earth Model ◽  
Data Sets ◽  
Data Set ◽  
Geoelectric Model ◽  
Controlled Source ◽  
The North ◽  
Electromagnetic Simulations

Synthetic data provided by geoelectric earth models are a powerful tool to evaluate a priori a controlled-source electromagnetic (CSEM) workflow effectiveness. Marlim R3D (MR3D) is an open-source complex and realistic geoelectric model for CSEM simulations of the postsalt turbiditic reservoirs at the Brazilian offshore margin. We have developed a 3D CSEM finite-difference time-domain forward study to generate the full-azimuth CSEM data set for the MR3D earth model. To that end, we fabricated a full-azimuth survey with 45 towlines striking the north–south and east–west directions over a total of 500 receivers evenly spaced at 1 km intervals along the rugged seafloor of the MR3D model. To correctly represent the thin, disconnected, and complex geometries of the studied reservoirs, we have built a finely discretized mesh of [Formula: see text] cells leading to a large mesh with a total of approximately 90 million cells. We computed the six electromagnetic field components (Ex, Ey, Ez, Hx, Hy, and Hz) at six frequencies in the range of 0.125–1.25 Hz. In our efforts to mimic noise in real CSEM data, we summed to the data a multiplicative noise with a 1% standard deviation. Both CSEM data sets (noise free and noise added), with inline and broadside geometries, are distributed for research or commercial use, under the Creative Common License, at the Zenodo platform.

A simplified model of effective elasticity for anisotropic shales

Geophysics ◽  
2009 ◽  
Vol 74 (3) ◽  
pp. D57-D63 ◽  
Author(s):  
Audrey Ougier-Simonin ◽  
Joël Sarout ◽  
Yves Guéguen
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Elastic Anisotropy ◽  
Solid Phase ◽  
Symmetry Plane ◽  
Sedimentary Basins ◽  
Bedding Plane ◽  
Analytical Models ◽  
Simple Method ◽  
Analysis Scheme

A simple method to deal with cracklike pores in anisotropic matrix rock such as shales enhances analytical models and their applications. Actually, clayrocks (shales, in particular) are the dominant clastic component in sedimentary basins, representing about two-thirds of all sedimentary rocks. Shales are usually assumed to be transversely isotropic (TI) media. They are known to be highly anisotropic because of (1) intrinsic elastic anisotropy of the solid phase (matrix) forming the rock (more or less ordered clay layers) and (2) anisotropy induced by the presence of cracklike pores. We focus on this second component of anisotropy. Current analytical models deal with it, but they are complex and are restricted in the case of matrix TI symmetry to cracks lying in the symmetry plane. We simplify such models within a reasonably good approximation and develop an analysis scheme in which cracklike pore effects are calculated in an equivalent isotropic matrix. This simplifies the theoretical approach and potentially broadens its application to any crack and/or pore orientation, e.g., damaged shale with horizontal and vertical (perpendicular to the bedding plane) cracks. A high-pressure confinement test provides experimental data for checking the proposed tool against a reference model in the case of cracklike pores lying in the bedding plane. The results (in terms of Thomsen parameters) are consistent with results from large-scale field data.

scholarly journals Conceptual model building inspired by field-mapped runoff generation mechanisms

2018 ◽  
Vol 66 (3) ◽  
pp. 303-315 ◽  
Author(s):  
Alberto Viglione ◽  
Magdalena Rogger ◽  
Herbert Pirkl ◽  
Juraj Parajka ◽  
Günter Blöschl
Keyword(s):  
Model Building ◽  
A Priori ◽  
Realistic Model ◽  
Model Parameters ◽  
Runoff Generation ◽  
Discharge Data ◽  
Lumped Model ◽  
Generation Mechanisms ◽  
The Right ◽  
Model Structures

Abstract Since the beginning of hydrological research hydrologists have developed models that reflect their perception about how the catchments work and make use of the available information in the most efficient way. In this paper we develop hydrologic models based on field-mapped runoff generation mechanisms as identified by a geologist. For four different catchments in Austria, we identify four different lumped model structures and constrain their parameters based on the field-mapped information. In order to understand the usefulness of geologic information, we test their capability to predict river discharge in different cases: (i) without calibration and (ii) using the standard split-sample calibration/ validation procedure. All models are compared against each other. Results show that, when no calibration is involved, using the right model structure for the catchment of interest is valuable. A-priori information on model parameters does not always improve the results but allows for more realistic model parameters. When all parameters are calibrated to the discharge data, the different model structures do not matter, i.e., the differences can largely be compensated by the choice of parameters. When parameters are constrained based on field-mapped runoff generation mechanisms, the results are not better but more consistent between different calibration periods. Models selected by runoff generation mechanisms are expected to be more robust and more suitable for extrapolation to conditions outside the calibration range than models that are purely based on parameter calibration to runoff data.

scholarly journals A Framework for Implementing Prediction Algorithm over Cloud Data as a Procedure for Cloud Data Mining

2021 ◽  
Vol 2 (2) ◽  
pp. 1-8
Author(s):  
Safwan A. S. Al-Shaibani ◽  
Keyword(s):  
Data Storage ◽  
Model Building ◽  
Cloud Services ◽  
Prediction Algorithm ◽  
Easy Access ◽  
Cloud Platform ◽  
Recent Past ◽  
Cloud Data ◽  
Platform As A Service ◽  
Post Surgery

The cloud has become an important phrase in data storage for many reasons. Cloud services and applications are widespread in many industries including healthcare due to easy access. The limitless quantity of data available on the clouds has triggered the interest of many researchers in the recent past. It has forced us to deploy machine learning for analyzing the data to get insights as well as model building. In this paper, we have built a service on Heroku Cloud which is a cloud platform as a service (PaaS) and has 15 thousand records with 25 features. The data belongs to healthcare and is related to post-surgery complications. The boost prediction algorithm was applied for analysis and implementation was done in python. The results helped us to determine and tune some of the hyperparameters which have correlations with complications and the reported accuracy of training and testing was found to be 91% and 88% respectively.

scholarly journals Disequilibrium Compaction, Fluid expansion and unloading effects: Analysis from well log and its pore pressure implication in Jay Field, Niger Delta

2020 ◽  
pp. 389-400 ◽  
Author(s):  
Chukwuemeka Patrick Abbey ◽  
Meludu Chukwudi Osita ◽  
Oniku Adetola Sunday ◽  
Mamman Yusuf Dabari
Keyword(s):  
Acoustic Wave ◽  
Pore Pressure ◽  
Niger Delta ◽  
Sedimentary Basins ◽  
Burial Depth ◽  
Well Log ◽  
Major Mechanism ◽  
Porosity And Permeability ◽  
Well Log Analysis ◽  
Pressure Regime

     Disequilibrium compaction, sometimes referred to as under compaction, has been identified as a major mechanism of abnormal pore pressure buildup in sedimentary basins. This is attributed to the interplay between the rate at which sediments are deposited and the rate at which fluids associated with the sediments are expelled with respect to burial depth. The purpose of this research is to analyze the mechanisms associated with abnormal pore pressure regime in the sedimentary formation. The study area “Jay field” is an offshore Niger Delta susceptible to abnormal pore pressure regime in the Agbada –Akata formations of the basin. Well log analysis and cross plots were applied to determine the under compacted zone in the formation since compaction increases with burial depth. It was observed that porosity and permeability of the deeper depth (3700 m to end of Well) are higher than those of the shallow part (3000 – 3700 m). This is against what is expected from normal compacted sediment, demonstrating disequilibrium compaction in deposition. Furthermore, it reveals that sedimentation rate was high, making it unable for the sediments to expunge its fluid as expected. Density and acoustic wave increase with depth in normal compaction trend. However, the reverse that was identified in the mapped interval is attributed to disequilibrium compaction, unloading, clay diagenesis, and fluid expansion. The cross plot divulges sediments at the deeper depth had lower density and acoustic wave value with increased porosity when compared to those at shallow depth. This forms the basis that the sediments from this mapped interval experienced disequilibrium and unloading traceable to clay diagenesis during and after deposition, respectively.

Seismic modelling of fault zones

2016 ◽  
Vol 56 (2) ◽  
pp. 599
Author(s):  
Emanuelle Frery ◽  
Laurent Langhi ◽  
Julian Strand ◽  
Jeffrey Shragge
Keyword(s):  
Elastic Properties ◽  
Fault Zone ◽  
Model Building ◽  
Rock Physics ◽  
Sedimentary Basins ◽  
Fault Zones ◽  
Base Case ◽  
Seismic Modelling ◽  
Seismic Image ◽  
Wide Range

While faults have long been known as primary pathways for fluid migration in sedimentary basins, recent work highlights the importance of fault zone internal architecture, lateral variation, transmissivity, and impact on migration and trapping. The impacts of fault zone architecture and properties on seismic images are investigated to facilitate accurately mapped fault zones, and to predict subseismic flow properties and sealing potential. A wedge-type fault model with a main fault and a synthetic fault displacing a typical North West Shelf siliciclastic succession is used to replicate the geometrical components of a seismic-scale fault. Elastic properties are derived from rock physics models, which are used in a 2D elastic modelling algorithm to produce realistic marine seismic acquisition geometry. These data were subsequently input into a 2D prestack (one-way wave-equation) migration code to produce an interpretable seismic image. Base-case elastic properties are systematically varied; modelling focuses on gouge properties, fractured fault zone material, the sandstone Vp/Vs relationship, and shale-sand velocity contrast. The workflow from geological model building to elastic property substitution and forward seismic modelling is extremely quick and versatile, allowing testing of a wide range of scenarios. So far this approach has yielded valuable insights into internal fault property prediction and interpretation of the fault zone in traditional post-stack seismic datasets. Implications for processing workflow and attenuation of fault shadows are also expected.

Fluids and lithofacies prediction based on integration of well-log data and seismic inversion: a machine learning approach

Geophysics ◽  
2021 ◽  
pp. 1-67
Author(s):  
Luanxiao Zhao ◽  
Caifeng Zou ◽  
Yuanyuan Chen ◽  
Wenlong Shen ◽  
Yirong Wang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Seismic Data ◽  
Domain Knowledge ◽  
Reservoir Characterization ◽  
Model Building ◽  
Imbalanced Data ◽  
Seismic Inversion ◽  
Well Log ◽  
Spatial Constraints ◽  
Imbalanced Data Sets

Seismic prediction of fluid and lithofacies distributions is of great interest to reservoir characterization, geological model building, and flow unit delineation. Inferring fluids and lithofacies from seismic data under the framework of machine learning is commonly subject to issues of limited features, imbalanced data sets, and spatial constraints. As a consequence, an XGBoost based workflow, which takes feature engineering, data balancing, and spatial constraints into account, is proposed to predict the fluid and lithofacies distribution by integrating well-log and seismic data. The constructed feature set based on simple mathematical operations and domain knowledge outperforms the benchmark group consisting of conventional elastic attributes of P-impedance and Vp/Vs ratio. A radial basis function characterizing the weights of training samples according to the distances from the available wells to the target region is developed to impose spatial constraints on the model training process, significantly improving the prediction accuracy and reliability of gas sandstone. The strategy combining the synthetic minority oversampling technique (SMOTE) and spatial constraints further increases the F1 score of gas sandstone and also benefits the overall prediction performance of all the facies. The application of the combined strategy on prestack seismic inversion results generates a more geologically reasonable spatial distribution of fluids, thus verifying the robustness and effectiveness of the proposed workflow.

A new petrophysical joint inversion workflow: Advancing on reservoir’s characterization challenges

2018 ◽  
Vol 6 (3) ◽  
pp. SG33-SG39 ◽  
Author(s):  
Fabio Miotti ◽  
Andrea Zerilli ◽  
Paulo T. L. Menezes ◽  
João L. S. Crepaldi ◽  
Adriano R. Viana
Keyword(s):  
Reservoir Characterization ◽  
Joint Inversion ◽  
Oil Field ◽  
Well Log ◽  
Complementary Information ◽  
Reservoir Properties ◽  
Reservoir Rocks ◽  
Controlled Source ◽  
Fluid Properties

Reservoir characterization objectives are to understand the reservoir rocks and fluids through accurate measurements to help asset teams develop optimal production decisions. Within this framework, we develop a new workflow to perform petrophysical joint inversion (PJI) of seismic and controlled-source electromagnetic (CSEM) data to resolve for reservoirs properties. Our workflow uses the complementary information contained in seismic, CSEM, and well-log data to improve the reservoir’s description drastically. The advent of CSEM, measuring resistivity, brought the possibility of integrating multiphysics data within the characterization workflow, and it has the potential to significantly enhance the accuracy at which reservoir properties and saturation, in particular, can be determined. We determine the power of PJI in the retrieval of reservoir parameters through a case study, based on a deepwater oil field offshore Brazil in the Sergipe-Alagoas Basin, to augment the certainty with which reservoir lithology and fluid properties are constrained.

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