Geological Elastic Properties and Offset-Incident Angle Relationship

Play an AI-generated podcast conversation about this lesson

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 (correct)

To determine the drilling velocity for the sand wedge model

To generate synthetic seismic gathers for various scenarios

To create a set of lithology replacement well logs

In the typical forward modelling workflow, what is performed after preparation of well logs?

Rock Physics study (correct)

Synthetic seismic gathers generation

Quality control and correction of Vp, Vs, and Density logs

Petrophysical interpretation for porosity, saturation, and lithology

What is the purpose of determining the resolvability limit within the reservoir?

To check consistency between seismic data and geological model

To understand the limit at which two features can be distinguished (correct)

To understand the seismic responses for different reservoir properties

To select attributes suitable for AVO analysis

What is one of the key steps involved in forward modeling?

Generation of synthetic seismic gathers (A) Signup and view all the answers

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 (C) Signup and view all the answers

What is the primary reason for conducting a Rock Physics study in the forward modelling process?

To understand how lithology affects AVO attributes (D) Signup and view all the answers

What is the main purpose of forward modeling in the Quantitative Interpretation workflow?

To create synthetic seismic data based on elastic rock properties (B) Signup and view all the answers

What does the lack of agreement between synthetic data and real recorded seismic data indicate?

The geological model is not correct (C) Signup and view all the answers

Why might sonic logs measure higher velocity in the washout zone of a gas saturated reservoir?

Due to the influence of the drill fluid (C) Signup and view all the answers

In forward modeling, what action may be required if synthetic trace amplitudes are weaker than real seismic data?

Perform fluid substitution (C) Signup and view all the answers

How can forward modeling help assess the plausibility of a geological model?

By generating synthetic data and comparing it with real seismic data (B) Signup and view all the answers

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 (A) Signup and view all the answers

What is the main purpose of forward modelling in seismic analysis?

To determine the seismic response changes for different geological parameters (B) Signup and view all the answers

Which model is considered the simplest method of forward modelling for seismic traces?

Convolution model (B) Signup and view all the answers

In AVO analysis, why is forward modelling essential?

To gain confidence in interpreting anomalies on seismic gathers (A) Signup and view all the answers

What causes a more intense seismic response according to the text?

High reflectivity (A) Signup and view all the answers

What happens to the amplitude with increasing incident angle in a wet sand top?

Decreases (C) Signup and view all the answers

Which AVO class shows a small P-impedance change but a large amplitude change on synthetic traces?

Class 2 (C) Signup and view all the answers

What is the expected behavior of the VP/VS ratio in a clean gas sand?

Decreases to 1.5 (B) Signup and view all the answers

What is needed to relate offsets to the incident angle in seismic modeling?

Travel time and velocity (B) Signup and view all the answers

What does a constant offset trace in seismic modeling result in?

Amplitudes from reflections with varying angles (C) Signup and view all the answers

What is the process of calculating the ray path from a source to a receiver in seismic modeling called?

Ray tracing (B) Signup and view all the answers

Which equation is commonly used along with ray tracing in seismic modeling to generate primary reflections?

Aki-Richards equation (D) Signup and view all the answers

What can be included in multi-layer AVO modeling beyond primary reflections?

Converted waves (A) Signup and view all the answers

In elastic wave modeling, what is affected by specifying a frequency range?

Run-time of the calculation (A) Signup and view all the answers

Which type of layers can primaries-only modeling inaccurately represent?

Thin layers (C) Signup and view all the answers

What do solid lines represent in the illustration of possible modelled events?

"Primaries-only" reflections (B) Signup and view all the answers

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. (A) Signup and view all the answers

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. (D) Signup and view all the answers

What is the primary focus of Image C in the presentation?

Double leg shear wave conversion (A) Signup and view all the answers

What does Elastic Wave Modeling offer that Zoeppritz Modeling doesn't?

Modeling of a wider range of effects (A) Signup and view all the answers

In seismic interpretation, what does tuning thickness refer to?

Critical thickness where amplitudes increase without impedance change (D) Signup and view all the answers

Why is considering anisotropy important in seismic data interpretation?

To prevent misinterpretations of AVO responses (A) Signup and view all the answers

Which modeled event incorporates both single and double leg shear waves according to the text?

Event C (C) Signup and view all the answers

What do Events E and F on the slide represent?

Wave equation modeling variations (D) Signup and view all the answers