scholarly journals Viscoelastic Model and Synthetic Seismic Data of Eastern Rub’Al-Khali

2021 ◽  
Vol 11 (4) ◽  
pp. 1401
Author(s):  
Septriandi A. Chan ◽  
Paul Edigbue ◽  
Sikandar Khan ◽  
Abdul L. Ashadi ◽  
Abdullatif A. Al-Shuhail
Keyword(s):  
Shear Wave ◽  
Seismic Data ◽  
Seismic Waves ◽  
Sand Dunes ◽  
Viscoelastic Model ◽  
Specific Area ◽  
Data Availability ◽  
Published Data ◽  
Quality Factors ◽  
Data Set

The Rub’ Al-Khali basin in Saudi Arabia remains unexplored and lacks data availability due to its remoteness and the challenging nature of its terrain. Thus far, there are neither digital geologic models nor synthetic seismic data from this specific area accessible for testing research techniques and analysis. In this study, we build a 2D viscoelastic model of the eastern part of the Rub’ Al-Khali basin and generate a corresponding dual-component seismic data set. We compile high-resolution depth models of compressional- and shear-wave velocities, density, as well as compressional- and shear-wave quality factors from published data. The compiled models span Neoproterozoic basement up to Quaternary sand dunes. We then use the finite-difference technique to model the propagation of seismic waves in the compiled viscoelastic medium of eastern Rub’ Al-Khali desert. In particular, we generate vertical and horizontal components of the shot gathers with accuracy to the fourth and second orders in space and time, respectively. The viscoelastic models and synthetic seismic datasets are made available in an open-source site for prospective re-searchers who desire to use them for their research. Users of these datasets are urged to make their findings also accessible to the geoscience community as a way of keeping track of developments related to the Rub’ Al-Khali desert.

Linear‐transform techniques for processing shear‐wave anisotropy in four‐component seismic data

Geophysics ◽  
1993 ◽  
Vol 58 (2) ◽  
pp. 240-256 ◽  
Author(s):  
Xiang‐Yang Li ◽  
Stuart Crampin
Keyword(s):  
Time Series ◽  
Shear Wave ◽  
Seismic Data ◽  
Shear Waves ◽  
Shear Wave Splitting ◽  
Data Set ◽  
Reflection Data ◽  
Wave Splitting ◽  
Linear Transform ◽  
Zero Offset

Most published techniques for analyzing shear‐wave splitting tend to be computing intensive, and make assumptions, such as the orthogonality of the two split shear waves, which are not necessarily correct. We present a fast linear‐transform technique for analyzing shear‐wave splitting in four‐component (two sources/ two receivers) seismic data, which is flexible and widely applicable. We transform the four‐component data by simple linear transforms so that the complicated shear‐wave motion is linearized in a wide variety of circumstances. This allows various attributes to be measured, including the polarizations of faster split shear waves and the time delays between faster and slower split shear waves, as well as allowing the time series of the faster and slower split shear waves to be separated deterministically. In addition, with minimal assumptions, the geophone orientations can be estimated for zero‐offset verticle seismic profiles (VSPs), and the polarizations of the slower split shear waves can be measured for offset VSPs. The time series of the split shear‐waves can be separated before stack for reflection surveys. The technique has been successfully applied to a number of field VSPs and reflection data sets. Applications to a zero‐offset VSP, an offset VSP, and a reflection data set will be presented to illustrate the technique.

scholarly journals A simple method to evaluate the air-to-ground coupling efficiency: a tool helping the assessment of seismic/infrasonic energy partitioning during an eruption

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Mie Ichihara ◽  
Kazuya Yamakawa ◽  
Dan Muramatsu
Keyword(s):  
Response Function ◽  
Seismic Data ◽  
Seismic Waves ◽  
Seismic Station ◽  
Coupling Efficiency ◽  
Data Set ◽  
Simple Method ◽  
Ground Shaking ◽  
Acoustic Data ◽  
Single Station

AbstractA volcanic eruption transmits both seismic and infrasound signals. The seismo-acoustic power ratio is widely used to investigate the eruption behaviors and the source dynamics. It is often the case that seismic data during an eruption are significantly contaminated or even dominated by ground shaking due to infrasound (air-to-ground signals). To evaluate the contribution of infrasound-originated power in the seismic data, we need a response function of the seismic station to infrasound. It is rare to obtain a seismo-acoustic data set containing only infrasound signals, though it is ideal for calculating the response function. This study proposes a simple way to calculate the response function using seismo-acoustic data containing infrasound and independent seismic waves. The method requires data recorded at a single station and mainly uses the cross-correlation function between the infrasound data and the Hilbert transform of the seismic data. It is tested with data recorded by a station at Kirishima volcano, Japan, of which response function has been constrained. It is shown that the method calculates a proper response function even when the seismic data contain more significant seismic power (or noise) than the air-to-ground signals. The proposed method will be useful in monitoring and understanding eruption behaviors using seismo-acoustic observations.

Empirical estimation of viscoelastic seismic parameters from petrophysical properties of sandstone

Geophysics ◽  
2001 ◽  
Vol 66 (5) ◽  
pp. 1457-1470 ◽  
Author(s):  
Adam P. Koesoemadinata ◽  
George A. McMechan
Keyword(s):  
Shear Wave ◽  
Water Saturation ◽  
Clay Content ◽  
Published Data ◽  
Effective Pressure ◽  
Petrophysical Properties ◽  
Quality Factors ◽  
Empirical Estimation ◽  
Reservoir Properties ◽  
Seismic Parameters

Viscoelastic seismic parameters are expressions of underlying petrophysical properties. Theoretical and empirically derived petrophysical/seismic relations exist, but each is limited in the number and the range of values of the variables used. To provide a more comprehensive empirical model, we combined lab measurements from 18 published data sets and well log data for sandstone samples, and determined least‐squares coefficients across them all. The dependent variables are the seismic parameters of bulk density (ρ), compressional and shear wave velocities ([Formula: see text] and [Formula: see text]), and compressional and shear wave quality factors ([Formula: see text] and [Formula: see text]). The independent variables are effective pressure, porosity, clay content, water saturation, permeability, and frequency. As the derived expressions are empirical correlations, no causal relations should be inferred. Prediction of ρ is based on volumetric mixing of the constituents. For [Formula: see text] and [Formula: see text] predictions, separate sets of coefficients are fitted for three water saturation conditions: dry, partially saturated, and fully saturated. Predictions of [Formula: see text] and [Formula: see text] are fitted as functions of porosity, clay content, effective pressure, saturation, and frequency. Predictions of [Formula: see text] are fitted as a function of porosity, clay content, permeability, saturation, frequency, and pressure. Interactions between effective pressure, saturation, and frequency are included. Predictions of [Formula: see text] are obtained from [Formula: see text] and [Formula: see text]. The result is a composite model that is more comprehensive than previous models and that predicts seismic properties from the petrophysical properties. Empirically estimated values of ρ, [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] for the composite data over all saturations predict the measurements with correlation coefficients [Formula: see text] that range from a low of 0.65 (for [Formula: see text],) to a high of 0.90 (for [Formula: see text]). As the fitted relations have been derived from data with limited parameter ranges, extrapolation is not advised, and they are not intended to substitute for locally derived relations based on site‐specific data. Nevertheless, the derived expressions produce representative values that will be useful when approximate, internally consistent predictions are sufficient. Potential future applications include building of seismic reservoir models from petrophysical data and analysis of the sensitivity of seismic data to changes in reservoir properties.

scholarly journals Imaging subtle faults using azimuthal coherence attribute: A case study from Central Saudi Arabia

GeoArabia ◽  
2012 ◽  
Vol 17 (4) ◽  
pp. 43-54
Author(s):  
Faisal Alqahtani ◽  
Abdullatif A. Al-Shuhail
Keyword(s):  
Saudi Arabia ◽  
Seismic Data ◽  
Seismic Waves ◽  
Detection Method ◽  
Gas Field ◽  
Data Set ◽  
Attribute Analysis ◽  
Edge Detection Method ◽  
Pass Through

ABSTRACT The coherence attribute is an edge detection method that is widely used for interpreting faults on 3-D seismic time slices. The traditional coherence attribute is calculated on migrated volumes using traces from all available azimuths. It has recently been shown that calculating coherence along specific azimuths can enhance the detection of faults running perpendicular to those azimuths. In this study, we applied azimuthal coherence attribute analysis on a 3-D seismic data set from a gas field in Central Saudi Arabia. We generated four migrated 3-D data volumes sorted by azimuth in addition to a conventional full-azimuth volume. We then calculated the coherence attribute for all volumes and compared each azimuthal coherence volume to the conventional full-azimuth coherence volume. The azimuthal coherence results exhibited an improved definition for faults whose strikes are perpendicular to the sorting azimuth. More specifically, systems of NW-trending discontinuities were imaged more clearly in the NE-SW oriented coherence volume than it was in the full-azimuth coherence volume. The reason for this enhancement is the fact that seismic waves tend to avoid passing through the fault when they propagate parallel to the fault strike therefore missing the effects of the fault while they must pass through the fault when propagating perpendicular to the fault strike which results in better illumination of the fault.

scholarly journals A simple method to evaluate the seismic/infrasonic energy partitioning during an eruption using data contaminated by air-to-ground signals

2021 ◽  
Author(s):  
Mie Ichihara ◽  
Kazuya Yamakawa ◽  
Dan Muramatsu
Keyword(s):  
Response Function ◽  
Seismic Data ◽  
Seismic Waves ◽  
Seismic Station ◽  
Acoustic Power ◽  
Data Set ◽  
Simple Method ◽  
Ground Shaking ◽  
Acoustic Data ◽  
Single Station

Abstract A volcanic eruption transmits both seismic waves and infrasound signals. The seismo-acoustic power ratio is widely used to investigate the eruption behaviors and the source dynamics. It is often the case that seismic data during an eruption are significantly contaminated or even dominated by ground shaking due to infrasound (air-to-ground signals). To evaluate the contribution of infrasound-originated power in the seismic data, we need a response function of the seismic station to infrasound. It is rare to obtain a seismo-acoustic data-set containing only infrasound signals, though it is ideal for calculating the response function. This study proposes a simple way to calculate the response function using seismo-acoustic data containing infrasound and independent seismic waves. The method requires data recorded at a single station and mainly uses the cross-correlation function between the infrasound data and the Hilbert transform of the seismic data. It is tested with data recorded by a station at Kirishima volcano, Japan, of which response function has been constrained. It is shown that the method calculates a proper response function even when the seismic data contain more significant seismic power (or noise) than the air-to-ground signals. The proposed method will be useful in monitoring and understanding eruption behaviors using seismo-acoustic observations.

Estimating P- and S-wave inverse quality factors from observed seismic data using an attenuative elastic impedance

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. R173-R187 ◽  
Author(s):  
Huaizhen Chen ◽  
Kristopher A. Innanen ◽  
Tiansheng Chen
Keyword(s):  
Seismic Data ◽  
Wave Attenuation ◽  
Synthetic Data ◽  
Real Data ◽  
Quality Factors ◽  
S Wave ◽  
Reservoir Prediction ◽  
Data Set ◽  
Elastic Impedance ◽  
Gas Bearing

P- and S-wave inverse quality factors quantify seismic wave attenuation, which is related to several key reservoir parameters (porosity, saturation, and viscosity). Estimating the inverse quality factors from observed seismic data provides additional and useful information during gas-bearing reservoir prediction. First, we have developed an approximate reflection coefficient and attenuative elastic impedance (QEI) in terms of the inverse quality factors, and then we established an approach to estimate elastic properties (P- and S-wave impedances, and density) and attenuation (P- and S-wave inverse quality factors) from seismic data at different incidence angles and frequencies. The approach is implemented as a two-step inversion: a model-based and damped least-squares inversion for QEI, and a Bayesian Markov chain Monte Carlo inversion for the inverse quality factors. Synthetic data tests confirm that P- and S-wave impedances and inverse quality factors are reasonably estimated in the case of moderate data error or noise. Applying the established approach to a real data set is suggestive of the robustness of the approach, and furthermore that physically meaningful inverse quality factors can be estimated from seismic data acquired over a gas-bearing reservoir.

Quest to delineate shale channel hazard in sandy reservoir

2014 ◽  
Vol 2 (2) ◽  
pp. SC37-SC46
Author(s):  
Jessa-lyn Lee
Keyword(s):  
Seismic Data ◽  
Development Program ◽  
Specific Area ◽  
Spatial Extent ◽  
Amplitude Variation ◽  
Data Set ◽  
Amplitude Variation With Offset ◽  
Lithology Prediction ◽  
Sand Bar ◽  
And Inversion

Using a combined amplitude-variation-with-offset (AVO) and inversion workflow, a 2D seismic data set was used to predict the lateral lithology changes in a sand bar deposit cut by shale-filled channels. Drilling into a shale channel drastically affects the success of a well, so understanding the spatial extent of such a feature is considered important to the economics of the development program. Based on results from extensive pre- and poststack modeling, a combination of AVO and inversion attributes provided the best chance at lithology prediction. Using this method, a channel map was created for a small study area. It is important to identify the risks and uncertainties intrinsic in the processes that are being applied as well as the effect of the overlying geology. This example in particular showed how vital it is to understand the geology in a specific area, know the technical limits of the data being used, and adapt workflows accordingly.

Financial distress determinants among SMEs: empirical evidence from Sweden

2020 ◽  
Vol 47 (3) ◽  
pp. 547-560 ◽  
Author(s):  
Darush Yazdanfar ◽  
Peter Öhman
Keyword(s):  
Financial Crisis ◽  
Financial Distress ◽  
Large Scale ◽  
Global Financial Crisis ◽  
Binary Logistic Regression ◽  
Data Availability ◽  
Cross Sectional ◽  
Data Set ◽  
Content Type ◽  
The Global Financial Crisis

PurposeThe purpose of this study is to empirically investigate determinants of financial distress among small and medium-sized enterprises (SMEs) during the global financial crisis and post-crisis periods.Design/methodology/approachSeveral statistical methods, including multiple binary logistic regression, were used to analyse a longitudinal cross-sectional panel data set of 3,865 Swedish SMEs operating in five industries over the 2008–2015 period.FindingsThe results suggest that financial distress is influenced by macroeconomic conditions (i.e. the global financial crisis) and, in particular, by various firm-specific characteristics (i.e. performance, financial leverage and financial distress in previous year). However, firm size and industry affiliation have no significant relationship with financial distress.Research limitationsDue to data availability, this study is limited to a sample of Swedish SMEs in five industries covering eight years. Further research could examine the generalizability of these findings by investigating other firms operating in other industries and other countries.Originality/valueThis study is the first to examine determinants of financial distress among SMEs operating in Sweden using data from a large-scale longitudinal cross-sectional database.

Effects of incomplete parameterization on full-wavefield viscoelastic seismic data for petrophysical reservoir properties

Geophysics ◽  
2007 ◽  
Vol 72 (3) ◽  
pp. O9-O17 ◽  
Author(s):  
Upendra K. Tiwari ◽  
George A. McMechan
Keyword(s):  
Seismic Data ◽  
Input Data ◽  
Elastic Model ◽  
Quality Factors ◽  
Noise Levels ◽  
Reservoir Properties ◽  
Estimated Parameters ◽  
Model Parameterization ◽  
The Earth ◽  
Incomplete Model

In inversion of viscoelastic full-wavefield seismic data, the choice of model parameterization influences the uncertainties and biases in estimating seismic and petrophysical parameters. Using an incomplete model parameterization results in solutions in which the effects of missing parameters are attributed erroneously to the parameters that are included. Incompleteness in this context means assuming the earth is elastic rather than viscoelastic. The inclusion of compressional and shear-wave quality factors [Formula: see text] and [Formula: see text] in inversion gives better estimates of reservoir properties than the less complete (elastic) model parameterization. [Formula: see text] and [Formula: see text] are sensitive primarily to fluid types and saturations. The parameter correlations are sensitive also to the model parameterization. As noise increases in the viscoelastic input data, the resolution of the estimated parameters decreases, but the parameter correlations are relatively unaffected by modest noise levels.

Estimating performance from capabilities in business process improvement

2016 ◽  
Vol 22 (6) ◽  
pp. 1099-1117 ◽  
Author(s):  
Boyd A. Nicholds ◽  
John P.T. Mo
Keyword(s):  
Process Improvement ◽  
Business Process ◽  
Expected Improvement ◽  
Management Decision ◽  
Published Data ◽  
Performance Gain ◽  
Data Set ◽  
Business Process Improvement ◽  
Improvement Project ◽  
Content Type

Purpose The research indicates there is a positive link between the improvement capability of an organisation and the intensity of effort applied to a business process improvement (BPI) project or initiative. While a degree of stochastic variation in applied effort to any particular improvement project may be expected there is a clear need to quantify the causal relationship, to assist management decision, and to enhance the chance of achieving and sustaining the expected improvement targets. The paper aims to discuss these issues. Design/methodology/approach The paper presents a method to obtain the function that estimates the range of applicable effort an organisation can expect to be able to apply based on their current improvement capability. The method used analysed published data as well as regression analysis of new data points obtained from completed process improvement projects. Findings The level of effort available to be applied to a process improvement project can be expressed as a regression function expressing the possible range of achievable BPI performance within 90 per cent confidence limits. Research limitations/implications The data set applied by this research is limited due to constraints during the research project. A more accurate function can be obtained with more industry data. Practical implications When the described function is combined with a separate non-linear function of performance gain vs effort a model of performance gain for a process improvement project as a function of organisational improvement capability is obtained. The probability of success in achieving performance targets may be estimated for a process improvement project. Originality/value The method developed in this research is novel and unique and has the potential to be applied to assessing an organisation’s capability to manage change.

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