A COMPARISON OF PHYSICAL MODEL WITH FIELD DATA OVER OLIVER FIELD, VULCAN GRABEN

1995 ◽  
Vol 35 (1) ◽  
pp. 26 ◽  
Author(s):  
B.J. Evans ◽  
B.F. Oke ◽  
M. Urosevic ◽  
K. Chakraborty
Keyword(s):  
Physical Model ◽  
Seismic Data ◽  
Field Data ◽  
Joint Venture ◽  
Survey Design ◽  
Three Dimensional ◽  
Physical Modelling ◽  
Field Work ◽  
Physical Models ◽  
2D And 3D

Physical models representing the three dimensional geology of oil fields can be built from materials such as plastics and resins. Using ultrasound transmitters and receivers, 2D and 3D seismic surveys can be simulated to aid in the survey design of field work, provide insight into data processing, and can test interpretation concepts. Such modelling simulates most aspects of both land and marine seismic.In 1993 BHP Petroleum, on behalf of the AC/P6 Joint Venture, contracted Curtin University's Geophysics Group to build a 1:40,000 scale, 11-layer, 2.5D model of the Oliver Field so that 2D and 3D field data acquisition and processing could be simulated. A 2.5D model is invariant in the strike direction, but can answer most of the questions of a true 3D model at a fraction of the effort and cost. This was the first such model built in Australia, and one of the most complex physical models ever built.Of interest was the quality of imaging under the fault shadow near reservoir level, and whether the application of dip or strike 3D acquisition and processing approaches could improve the seismic data quality. Consequently, both dip (2D) and strike (2.5D) seismic data were acquired over the model using similar parameters to those used in conventional offshore acquisition. The data were processed to migration stage and compared with the field seismic data. Numerical model and field VSP data were also processed and compared with the field and physical model seismic data.The good agreement between processed physical model seismic and field seismic shows that physical modelling of geology has application in both two and three dimensional interpretation, acquisition planning, and processing testing and optimisation.This physical model experiment proved conclusively that shallow faults with a relatively large velocity contrast across them cause 'back' faults on the seismic data which do not exist in reality. Furthermore, this experiment proved for the first time using a physical model that strike 3D marine recording is preferable to dip 3D marine recording.

Multidirectional eigenvalue-based coherence attribute for discontinuity detection

Geophysics ◽  
2021 ◽  
pp. 1-48
Author(s):  
Binpeng Yan ◽  
Ruirui Fang ◽  
Xingguo Huang ◽  
Weiming Ou
Keyword(s):  
Physical Model ◽  
Seismic Data ◽  
Field Data ◽  
Seismic Interpretation ◽  
Covariance Matrices ◽  
The Other ◽  
Computationally Efficient ◽  
Discontinuity Detection ◽  
Geological Discontinuities ◽  
Parallel Direction

The conventional coherence attribute is typically applied to migrated full-stacked seismic data volumes to detect geological discontinuities. Recently, multispectral, multiazimuth, and multioffset coherence attributes have been proposed and implemented with different seismic data volumes of specific frequencies, azimuths, and offsets to enhance discontinuities. Generally, geological anomalies, such as faults and channels, will be better illuminated by a perpendicular rather than a parallel direction for computation. Therefore, we propose a multidirectional eigenvalue-based coherence attribute by establishing multiple covariance matrices along certain different directions on a single post-stack volume. We adopt two methods to compute multidirectional coherence attribute. One is to compute multiple coherence volumes in different directions and to define the minimum as the final multidirectional coherence. This method is time-consuming, but could provide partial and overall discontinuity simultaneously. The other method obtains one coherence volume by summing covariance matrices in different directions, which is computationally efficient, but only provides overall discontinuity. The performance of 3D physical model and field data volumes demonstrates that multidirectional coherence can highlight subtle geologic structures with a higher resolution than conventional coherence. This suggests that multidirectional coherence attribute may serve as an effective tool for detecting the distribution of geologic discontinuities in seismic interpretation.

THE SEISMIC EXPRESSION OF THREE-DIMENSIONAL SANDBOX MODELS

1996 ◽  
Vol 36 (1) ◽  
pp. 490
Author(s):  
D.H. Sherlock ◽  
B.J. Evans ◽  
C.C. Ford
Keyword(s):  
Seismic Data ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Physical Modelling ◽  
Seismic Wave Propagation ◽  
Construction Time ◽  
Geological Structures ◽  
Seismic Modelling ◽  
Solid Models ◽  
First Time

Analogue sandbox models provide cheap, concise data and allow the evolution of geological structures to be observed under controlled conditions in a laboratory. Seismic physical modelling is used to study the effects of seismic wave propagation in isotropic and anisotropic media and to improve methods of data acquisition, processing and interpretation. These two independent geological modelling techniques have been linked for the first time, to combine and expand the existing benefits of each method.Seismic physical modelling to date has employed solid models, constructed with pre-determined structures built into the model. Previous attempts to adapt this technology to unconsolidated materials failed due to the severe energy attenuation of seismic waves in cohesionless grain matrices, and excessive signal scatter due to scaling limitations of the geological feature size to wavelength ratio. This paper presents our research to overcome these problems and thereby allow the successful seismic imaging of sandbox models.A number of techniques have been developed to combine these two independent modelling methods and results show that it is possible to image several layers within the models, demonstrating the potential to interpret complex geological structures within such models. For seismic modelling, the main advantages are that the seismic data collected from these models contain natural variation that cannot be built into solid models, which results in a more realistic image, and the cost and construction time of the models are also dramatically reduced. For sandbox modelling, the recording of seismic data over them allows far more detailed interpretation of the structures than previously possible and also allows direct comparison with field data for the first time, to substantiate or negate an existing interpretation.

Interferometric prediction and subtraction of surface waves with a nonlinear local filter

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. SI1-SI8 ◽  
Author(s):  
Yanwei Xue ◽  
Shuqian Dong ◽  
Gerard T. Schuster
Keyword(s):  
Surface Waves ◽  
Seismic Data ◽  
Field Data ◽  
Matched Filter ◽  
Parameter Selection ◽  
Coherent Noise ◽  
Interferometric Method ◽  
3D Data ◽  
2D And 3D ◽  
Selection Of

Surface waves are a form of coherent noise that can obscure valuable reflection information in exploration records. It is sometimes difficult to eliminate these surface waves by traditional filtering approaches, such as an [Formula: see text] filter, without damaging the useful signals. As a partial remedy, we propose an interferometric method to predict and subtract surface waves in seismic data. The removal of surface waves by the proposed interferometric method consists of three steps: (1) remove most of the surface waves by a nonlinear local filter; (2) predict the residual surface waves by the interferometric method; (3) separate the residual surface waves from the result of step 2 by a nonlinear local filter, and remove the residual surface waves by a matched filter from the result of step 1. Field data tests for 2D and 3D data show that the method effectively suppresses surface waves and preserves the reflection information. Results suggest that the effectiveness of this method is sensitive to the parameter selection of the nonlinear local filter.

scholarly journals Three-Dimensional Physical and Numerical Modelling of Fracturing and Deformation Behaviour of Mining-Induced Rock Slopes

2019 ◽  
Vol 9 (7) ◽  
pp. 1360 ◽  
Author(s):  
Guoxiang Yang ◽  
Anthony K. Leung ◽  
Nengxiong Xu ◽  
Kunxiang Zhang ◽  
Kunpeng Gao
Keyword(s):  
Rock Mass ◽  
Numerical Modelling ◽  
Physical Model ◽  
Rock Slope ◽  
Rock Joint ◽  
Three Dimensional ◽  
Physical Modelling ◽  
Rock Slopes ◽  
Rock Mass Structure ◽  
Iron Mine

Fracturing behaviour of jointed rock mass subjected to mining can significantly affect the stability of the rock structures and rock slopes. Ore mining within an open-pit final slope would lead to large-scale strata and surface movement of the rock slope. Rock mass structure, or more specifically, the strength, spacing and distribution of rock joints, are the controlling factors that govern the failure and deformation mechanisms of the final slope. Two-dimensional (2-D) physical modelling tests have been conducted in the literature, but in general, most of them have simplified the geological conditions and neglected some key features of rock mass structure in the field. In this study, new three-dimensional (3-D) physical modelling methods are introduced, with realistic modelling of mechanical behaviour of rock mass as well as identified properties of predominant rock joint sets. A case study of Yanqianshan iron mine is considered and the corresponding 1:200 model rock slope was created for studying the rock joint effects on the strata movement and the subsidence mechanism of the slope. The physical model test results are subsequently verified with 3-D discrete element numerical modelling. Due to the presence of the predominant joints, the observed well-shaped strata subsidence in Yanqianshan iron mine was successfully reproduced in the 3-D physical model. The failure mechanism of rock slopes differs from the trumpet-shaped subsidence observed in unconsolidated soil. Due to the formation of an arching mechanism within the rock mass, the strata deformation transferred gradually from the roof of the goaf to the slope surface.

Comparison between InfoWorks hydraulic results and a physical model of an urban drainage system

2013 ◽  
Vol 68 (2) ◽  
pp. 372-379 ◽  
Author(s):  
Matteo Rubinato ◽  
James Shucksmith ◽  
Adrian J. Saul ◽  
Will Shepherd
Keyword(s):  
Physical Model ◽  
Drainage System ◽  
Physical Modelling ◽  
Physical Models ◽  
Scale Model ◽  
Urban Drainage ◽  
Urban Flood ◽  
Drainage Systems ◽  
Physical Scale ◽  
Urban Drainage Systems

Urban drainage systems are frequently analysed using hydraulic modelling software packages such as InfoWorks CS or MIKE-Urban. The use of such modelling tools allows the evaluation of sewer capacity and the likelihood and impact of pluvial flood events. Models can also be used to plan major investments such as increasing storage capacity or the implementation of sustainable urban drainage systems. In spite of their widespread use, when applied to flooding the results of hydraulic models are rarely compared with field or laboratory (i.e. physical modelling) data. This is largely due to the time and expense required to collect reliable empirical data sets. This paper describes a laboratory facility which will enable an urban flood model to be verified and generic approaches to be built. Results are presented from the first phase of testing, which compares the sub-surface hydraulic performance of a physical scale model of a sewer network in Yorkshire, UK, with downscaled results from a calibrated 1D InfoWorks hydraulic model of the site. A variety of real rainfall events measured in the catchment over a period of 15 months (April 2008–June 2009) have been both hydraulically modelled and reproduced in the physical model. In most cases a comparison of flow hydrographs generated in both hydraulic and physical models shows good agreement in terms of velocities which pass through the system.

scholarly journals PRONY FILTERING OF SEISMIC DATA: MATHEMATICAL AND PHYSICAL MODELLING

2013 ◽  
Vol 31 (1) ◽  
pp. 151 ◽  
Author(s):  
Georgy Mikhailovich Mitrofanov ◽  
Viatcheslav Ivanovich Priimenko
Keyword(s):  
Seismic Data ◽  
Physical Modelling ◽  
Parameters Estimation ◽  
Physical Models ◽  
Seismic Signals ◽  
Optimal Method ◽  
Filtering Method ◽  
Local Areas ◽  
The Media

This article presents results of the Prony filtering method testing using mathematical and physical models. They illustrate features and capabilities of the proposed method of processing and analysing the recorded signals, which also include reflected seismic signals. Guidelines for choosing the optimal method parameters are demonstrated using examples. The use of such parameters provides the best extraction and parameters estimation of target signals. Based on them, it allows us to analyse the absorbing and scattering properties of the media for the local areas, for the analysed reflectors in particular. RESUMO: Este artigo teve por objetivo apresentar e analisar os resultados da aplicação do método de filtragem de Prony em modelos físicos e matemáticos. Tais resultados ilustram as características e o potencial do método proposto no processamento e na análise de sinais, incluindo também os eventos sísmicos de reflexão. As diretrizes para escolher os parâmetros otimizados do método são demonstradas através de exemplos. O uso de tais parâmetros proporciona a melhor estimativa, e viabiliza a separação dos sinais alvo. Com base em tais sinais, é possível analisar as propriedades de absorção e dispersão dos meios em áreas locais, em particular, nos refletores analisados.Palavras-chave: transformada de prony; decomposição de sinal e filtragem; dispersão e absorção de energia sísmica; efeitos de frequência

Evaluation of two‐pass three‐dimensional migration

Geophysics ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 32-49 ◽  
Author(s):  
John A. Dickinson
Keyword(s):  
Seismic Data ◽  
Field Data ◽  
Three Dimensional ◽  
Velocity Variation ◽  
Lateral Velocity ◽  
Data Manipulation ◽  
Depth Migration ◽  
Data Comparison ◽  
Time Migration ◽  
Order Of Magnitude

The theoretically correct way to perform a three‐dimensional (3-D) migration of seismic data requires large amounts of data manipulation on the computer. In order to alleviate this problem, a true, one‐pass 3-D migration is commonly replaced with an approximate technique in which a series of two‐dimensional (2-D) migrations is performed in orthogonal directions. This two‐pass algorithm produces the correct answer when the velocity is constant, both horizontally and vertically. Here I analyze the error due to this algorithm when the velocities vary vertically. The analysis has two parts: first, a theoretical analysis is performed in which a formula for the error is derived; and second, a field data comparison between one‐pass and two‐pass migrations is shown. My conclusion is that two‐pass 3-D migration is, in general, a very good approximation. Its errors are usually small, the exceptions being when both the reflector dip is large (in practice this typically means greater than about 25 to 40 degrees) and the orientation of the reflector is in neither the inline nor the crossline direction. Even then the error is the same order of magnitude as that due to the uncertainty in the migration velocities. These conclusions are still valid when there is lateral velocity variation, as long as this variation is accounted for by trace stretching. The analysis presented here deals with time migration; no claims are made regarding depth migration.

Optimization of Rock Berms for Pipeline Stabilization Subject to Intense Hydrodynamic Forcing

2015 ◽  
Author(s):  
Andrew Cornett ◽  
Scott Baker ◽  
Peter Riedel ◽  
Paul Knox
Keyword(s):  
Tropical Cyclones ◽  
Three Dimensional ◽  
Large Data ◽  
Physical Modelling ◽  
Cost Effective ◽  
Data Set ◽  
Waves And Currents ◽  
2D And 3D ◽  
Water Depths ◽  
Comprehensive Study

This article describes a comprehensive study in which 2D and 3D physical modelling at 1:40 scale was used to optimize the design and validate the performance of dynamically stable rock berms to be used for stabilizing several large pipelines traversing water depths from 5m to 65m and potentially exposed to large waves and strong currents generated by intense tropical cyclones. For added realism, all of the model rock berms were constructed using a scaled simulation of rock installation by fall pipe vessel to be used in the field. Special attention was also given to simulating the self-stability of the model pipeline segments, including special end constraints designed to mimic the behaviour of a continuous pipeline. A large data set concerning the behaviour of dynamically reshaping rock berms in a range of water depths under intense hydrodynamic forcing due to three-dimensional waves and currents was produced and used to develop efficient and cost-effective rock berm designs for all depth zones.

MEASUREMENT OF PRESSURE RESPONSES IN A PHYSICAL MODEL OF A HUMAN HEAD WITH HIGH SHAPE FIDELITY BASED ON CT/MRI DATA

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1718-1723
Author(s):  
YUSUKE MIYAZAKI ◽  
HIROSHI TACHIYA ◽  
KENJI ANATA ◽  
AKIHIRO HOJO
Keyword(s):  
Physical Model ◽  
Three Dimensional ◽  
Human Head ◽  
Physical Models ◽  
Positive Pressure ◽  
Head Model ◽  
Absolute Maximum ◽  
Brain Contusion ◽  
The Impact ◽  
Impacted Site

This study discusses a head injury mechanism in case of a human head subjected to impact, from results of impact experiments by using a physical model of a human head with high-shape fidelity. The physical model was constructed by using rapid prototyping technology from the three-dimensional CAD data, which obtained from CT/MRI images of a subject's head. As results of the experiments, positive pressure responses occurred at the impacted site, whereas negative pressure responses occurred at opposite the impacted site. Moreover, the absolute maximum value of pressure occurring at the frontal region of the intracranial space of the head model resulted in same or higher than that at the occipital site in each case that the impact force was imposed on frontal or occipital region. This result has not been showed in other study using simple shape physical models. And, the result corresponds with clinical evidences that brain contusion mainly occurs at the frontal part in each impact direction. Thus, physical model with accurate skull shape is needed to clarify the mechanism of brain contusion.

Autocorrelogram migration: Theory

Geophysics ◽  
2003 ◽  
Vol 68 (5) ◽  
pp. 1685-1694 ◽  
Author(s):  
Gerard T. Schuster ◽  
Fred Followill ◽  
Lewis J. Katz ◽  
Jianhua Yu ◽  
Zhaojun Liu
Keyword(s):  
Seismic Data ◽  
Field Data ◽  
Seismic Profile ◽  
Coherent Noise ◽  
Direct Wave ◽  
Pilot Signal ◽  
Source Signal ◽  
2D And 3D ◽  
Direct Primary ◽  
Imaging Conditions

We present the equations for migrating inverse‐vertical‐seismic‐profile‐while‐drilling and common‐midpoint autocorrelograms. These equations partly generalize the 1D autocorrelation imaging methods of Katz and Claerbout to 2D and 3D media, and also provide a formal mathematical procedure for imaging the reflectivity distribution from autocorrelograms. The imaging conditions are designed to migrate specific events in the autocorrelograms, either the direct‐primary correlations or the direct‐ghost correlations. Here, direct stands for direct wave, primary stands for primary reflections, and ghost denotes free‐surface ghost reflections. The main advantage in migrating autocorrelograms is that the source wavelet does not need to be known, which is the case for seismic data generated by a rotating drill bit or for vibroseis data with a corrupted pilot signal. Another advantage is that the source and receiver static problems are mitigated by autocorrelation migration. Two limitations are that autocorrelation of traces amplifies coherent noise such as surface waves, and produces undesirable coherent noise denoted as “virtual multiples.” Similar to “physical multiples,” such noise can, in principle, be partially suppressed by filtering and stacking of migration images obtained from many different shot gathers. Results with both synthetic and field data validate this conjecture, and show that autocorrelogram migration can be a viable alternative to standard migration when the source signal is not adequately known or there are severe static problems.

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