35 Questions
What is the main purpose of AVO modelling in the interpretation process?
To understand how seismic responses change for different fluid types and reservoir properties
In the typical forward modelling workflow, what is performed after preparation of well logs?
Rock Physics study
What is the purpose of determining the resolvability limit within the reservoir?
To understand the limit at which two features can be distinguished
What is one of the key steps involved in forward modeling?
Generation of synthetic seismic gathers
Why is AVO modelling considered a fundamental part of the interpretation process?
To determine how seismic responses vary across different fluid types, porosity, and thickness
What is the primary reason for conducting a Rock Physics study in the forward modelling process?
To understand how lithology affects AVO attributes
What is the main purpose of forward modeling in the Quantitative Interpretation workflow?
To create synthetic seismic data based on elastic rock properties
What does the lack of agreement between synthetic data and real recorded seismic data indicate?
The geological model is not correct
Why might sonic logs measure higher velocity in the washout zone of a gas saturated reservoir?
Due to the influence of the drill fluid
In forward modeling, what action may be required if synthetic trace amplitudes are weaker than real seismic data?
Perform fluid substitution
How can forward modeling help assess the plausibility of a geological model?
By generating synthetic data and comparing it with real seismic data
What is a common outcome if there is an agreement with acceptable accuracy between synthetic and real seismic data?
The geological model is considered plausible
What is the main purpose of forward modelling in seismic analysis?
To determine the seismic response changes for different geological parameters
Which model is considered the simplest method of forward modelling for seismic traces?
Convolution model
In AVO analysis, why is forward modelling essential?
To gain confidence in interpreting anomalies on seismic gathers
What causes a more intense seismic response according to the text?
High reflectivity
What happens to the amplitude with increasing incident angle in a wet sand top?
Decreases
Which AVO class shows a small P-impedance change but a large amplitude change on synthetic traces?
Class 2
What is the expected behavior of the VP/VS ratio in a clean gas sand?
Decreases to 1.5
What is needed to relate offsets to the incident angle in seismic modeling?
Travel time and velocity
What does a constant offset trace in seismic modeling result in?
Amplitudes from reflections with varying angles
What is the process of calculating the ray path from a source to a receiver in seismic modeling called?
Ray tracing
Which equation is commonly used along with ray tracing in seismic modeling to generate primary reflections?
Aki-Richards equation
What can be included in multi-layer AVO modeling beyond primary reflections?
Converted waves
In elastic wave modeling, what is affected by specifying a frequency range?
Run-time of the calculation
Which type of layers can primaries-only modeling inaccurately represent?
Thin layers
What do solid lines represent in the illustration of possible modelled events?
"Primaries-only" reflections
What is necessary to perform forward modeling to calculate travel times and incident angles in seismic analysis?
Thickness and S-wave velocity in multiple layers.
In AVO program, what is necessary for creating a stack of N layers?
Well logs and defining thickness, P-wave velocity, S-wave velocity, and density for each layer.
What is the primary focus of Image C in the presentation?
Double leg shear wave conversion
What does Elastic Wave Modeling offer that Zoeppritz Modeling doesn't?
Modeling of a wider range of effects
In seismic interpretation, what does tuning thickness refer to?
Critical thickness where amplitudes increase without impedance change
Why is considering anisotropy important in seismic data interpretation?
To prevent misinterpretations of AVO responses
Which modeled event incorporates both single and double leg shear waves according to the text?
Event C
What do Events E and F on the slide represent?
Wave equation modeling variations
Test your knowledge on the relationship between offsets, incident angles, and amplitude changes in geological elastic properties. Explore the nonlinear relationship between these factors and how trigonometry can be used to derive equations related to offset and incident angle.
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