Q-model building using one-way wave-equation migration Q analysis — Part 1: Theory and synthetic test

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. S93-S109 ◽  
Author(s):  
Yi Shen ◽  
Biondo Biondi ◽  
Robert Clapp
Keyword(s):  
Wave Equation ◽  
Model Building ◽  
Estimation Method ◽  
Improve Image Quality ◽  
Seismic Migration ◽  
Seismic Image ◽  
Complex Wave ◽  
Q Model ◽  
Synthetic Test ◽  
Text Model

The goal of this study is to understand and quantify the attenuation effects in the subsurface and to create an accurate laterally and vertically varying quality factor [Formula: see text] model for gas clouds/pockets. Such [Formula: see text] models are used in seismic migration to improve image quality. We evaluate an inversion-based method, wave-equation migration [Formula: see text] analysis, with two major features. First, this method is performed in the image space to reduce noise, focus events, and provide a direct link between [Formula: see text] model perturbations and image perturbations. Second, this method uses wave-equation-based [Formula: see text] tomography to handle the complex wave propagation. We apply this method to three 2D synthetic examples. The numerical synthetic tests of this [Formula: see text] estimation method demonstrate its feasibility on characterizing [Formula: see text] anomalies and, as a consequence, improving the seismic image.

Q-model building using one-way wave-equation migration Q analysis — Part 2: 3D field-data test

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. S111-S126 ◽  
Author(s):  
Yi Shen ◽  
Biondo Biondi ◽  
Robert Clapp
Keyword(s):  
Wave Equation ◽  
Model Building ◽  
Velocity Model ◽  
Seismic Attenuation ◽  
Low Velocity ◽  
Data Set ◽  
The North ◽  
Q Model ◽  
Text Model ◽  
Interval Velocities

We previously evaluated an inversion-based method, wave-equation migration [Formula: see text] analysis (WEMQA), to estimate the quality factor [Formula: see text] model for seismic attenuation. To demonstrate the feasibility of this method, we applied this method to a 3D seismic data set acquired in the North Sea. Attenuation problems caused by a shallow gas and a shallow channel are observed in this field. We aim to characterize these attenuation anomalies. These attenuation anomalies are correlated with low interval velocities. The provided velocity model does not accurately reflect the low-velocity anomalies. Therefore, we first applied wave-equation migration velocity analysis to update the provided velocity model. The updated velocity shows low-velocity regions around the gas and channel features. The subsurface angle gathers migrated using the updated velocity model are flatter, and the events in the migrated images after velocity updating are more coherent. Then, we applied WEMQA [Formula: see text] to invert for the [Formula: see text] model. The inverted [Formula: see text] model detects the shape and location of the gas and channel. Consequently, the migration with the estimated [Formula: see text] anomalies enhances the damped amplitudes and the frequency content of the migrated events corrects the distorted phase of the migrated events and makes them more coherent.

Theoretical, methodological and practical issues of choice models

2018 ◽  
Vol 1 (1) ◽  
pp. 21-37
Author(s):  
Bharat P. Bhatta
Keyword(s):  
Discrete Choice ◽  
Model Building ◽  
Estimation Method ◽  
Choice Models ◽  
Discrete Choice Models ◽  
Decision Makers ◽  
Model Formulation ◽  
Random Utility Maximization ◽  
The Relationship ◽  
Method Model

This paper analyzes and synthesizes the fundamentals of discrete choice models. This paper alsodiscusses the basic concept and theory underlying the econometrics of discrete choice, specific choicemodels, estimation method, model building and tests, and applications of discrete choice models. Thiswork highlights the relationship between economic theory and discrete choice models: how economictheory contributes to choice modeling and vice versa. Keywords: Discrete choice models; Random utility maximization; Decision makers; Utility function;Model formulation

No-scale supergravity inflation: A bridge between string theory and particle physics?

2016 ◽  
Vol 25 (14) ◽  
pp. 1630027 ◽  
Author(s):  
John Ellis
Keyword(s):  
Supergravity Models ◽  
String Theory ◽  
Effective Potential ◽  
Particle Physics ◽  
Model Building ◽  
Inflationary Model ◽  
New Wave ◽  
Microwave Background ◽  
Supergravity Theory ◽  
Text Model

The plethora of recent and forthcoming data on the cosmic microwave background (CMB) data are stimulating a new wave of inflationary model-building. Naturalness suggests that the appropriate framework for models of inflation is supersymmetry. This should be combined with gravity in a supergravity theory, whose specific no-scale version has much to commend it, e.g. its derivation from string theory and the flat directions in its effective potential. Simple no-scale supergravity models yield predictions similar to those of the Starobinsky [Formula: see text] model, though some string-motivated versions make alternative predictions. Data are beginning to provide interesting constraints on the rate of inflaton decay into Standard Model particles. In parallel, LHC and other data provide significant constraints on no-scale supergravity models, which suggest that some sparticles might have masses close to present experimental limits.

Integrated VTI model building with seismic data, geologic information, and rock-physics modeling — Part 1: Theory and synthetic test

Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. C177-C191 ◽  
Author(s):  
Yunyue Li ◽  
Biondo Biondi ◽  
Robert Clapp ◽  
Dave Nichols
Keyword(s):  
Seismic Data ◽  
Seismic Anisotropy ◽  
Model Building ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Additional Information ◽  
Synthetic Test ◽  
Rock Physics Modeling ◽  
Physics Modeling ◽  
Geologic Information

Seismic anisotropy plays an important role in structural imaging and lithologic interpretation. However, anisotropic model building is a challenging underdetermined inverse problem. It is well-understood that single component pressure wave seismic data recorded on the upper surface are insufficient to resolve a unique solution for velocity and anisotropy parameters. To overcome the limitations of seismic data, we have developed an integrated model building scheme based on Bayesian inference to consider seismic data, geologic information, and rock-physics knowledge simultaneously. We have performed the prestack seismic inversion using wave-equation migration velocity analysis (WEMVA) for vertical transverse isotropic (VTI) models. This image-space method enabled automatic geologic interpretation. We have integrated the geologic information as spatial model correlations, applied on each parameter individually. We integrate the rock-physics information as lithologic model correlations, bringing additional information, so that the parameters weakly constrained by seismic are updated as well as the strongly constrained parameters. The constraints provided by the additional information help the inversion converge faster, mitigate the ambiguities among the parameters, and yield VTI models that were consistent with the underlying geologic and lithologic assumptions. We have developed the theoretical framework for the proposed integrated WEMVA for VTI models and determined the added information contained in the regularization terms, especially the rock-physics constraints.

Full Wavefield Redatuming: Accurate Velocity Modelling for Imaging Beneath Complex Overburden

2021 ◽  
Author(s):  
Farah Syazana Dzulkefli ◽  
Kefeng Xin ◽  
Ahmad Riza Ghazali ◽  
Guo Qiang ◽  
Tariq Alkhalifah
Keyword(s):  
Wave Propagation ◽  
Seismic Data ◽  
Model Building ◽  
Velocity Model ◽  
Surrounding Rock ◽  
Target Area ◽  
Low Density ◽  
Velocity Model Building ◽  
Seismic Image ◽  
Seismic Wavefield

Abstract Salt is known for having a generally low density and higher velocity compared with the surrounding rock layers which causes the energy to scatter once the seismic wavefield hits the salt body and relatively less energy is transmitted through the salt to the deeper subsurface. As a result, most of imaging approaches are unable to image the base of the salt and the reservoir below the salt. Even the velocity model building such as FWI often fails to illuminate the deeper parts of salt area. In this paper, we show that Full Wavefield Redatuming (FWR) is used to retrieved and enhance the seismic data below the salt area, leading to a better seismic image quality and allowing us to focus on updating the velocity in target area below the salt. However, this redatuming approach requires a good overburden velocity model to retrieved good redatumed data. Thus, by using synthetic SEAM model, our objective is to study on the accuracy of the overburden velocity model required for imaging beneath complex overburden. The results show that the kinematic components of wave propagation are preserved through redatuming even with heavily smoothed overburden velocity model.

Frequency-dependent seismic analysis: Data processing, modeling, and interpretation

2019 ◽  
Vol 38 (7) ◽  
pp. 556-557
Author(s):  
Yi Shen ◽  
Kui Bao ◽  
Doug Foster ◽  
Dhananjay Kumar ◽  
Kris Innanen ◽  
...  
Keyword(s):  
Model Building ◽  
Seismic Analysis ◽  
Rock Physics ◽  
Analysis Data ◽  
Seismic Interpretation ◽  
Seismic Attenuation ◽  
Frequency Dependent ◽  
University Of Texas ◽  
Q Model ◽  
Physics Modeling

A one-day postconvention workshop held during the 2018 SEG Annual Meeting in Anaheim, California, focused on seismic attenuation model building and compensation through imaging in the morning and on frequency-dependent seismic interpretation and rock physics in the afternoon. The workshop was organized by Dhananjay Kumar (BP), Yi Shen (Shell), Kui Bao (Shell), Mark Chapman (University of Edinburgh), Doug Foster (The University of Texas at Austin), Wenyi Hu (Advanced Geophysical Tech Inc.), and Tieyuan Zhu (Pennsylvania State University). The main topics discussed were: attenuation and Q model building using seismic, vertical seismic profiling, well-log and core data, seismic attenuation compensation, rock-physics modeling, seismic modeling, and frequency-dependent seismic interpretation.

scholarly journals Seismic migration of blended shot records with surface-related multiple scattering

Geophysics ◽  
2011 ◽  
Vol 76 (1) ◽  
pp. A7-A13 ◽  
Author(s):  
D. J. (Eric) Verschuur ◽  
A. J. (Guus) Berkhout
Keyword(s):  
Multiple Scattering ◽  
Input Data ◽  
Green's Functions ◽  
Green’S Functions ◽  
Migration Process ◽  
Seismic Migration ◽  
Seismic Image ◽  
Blended Data

This paper focuses on the concept of using blended data and multiple scattering directly in the migration process, meaning that the blended input data for the proposed migration algorithm includes blended surface-related multiples. It also means that both primary and multiple scattering contribute to the seismic image of the subsurface. Essential in our approach is that multiples are not included in the Green’s functions but are part of the incident wavefields, utilizing the so-called double illumination property. We find that complex incident wavefields, such as blended primaries and/or blended multiples, require a reformulation of the imaging principle in order to provide broadband angle-dependent reflection properties.

Sign in / Sign up

Export Citation Format

Share Document