Elastic Impedance and AVO Inversion

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What does this module aim to explore?

Impact of seismic signals on reservoir characterization

Qualitative interpretation of seismic amplitudes

Typical processes in seismic inversion

Quantitative description of reservoir properties using amplitudes (correct)

What is the reflection coefficient R proportional to at normal incidence?

Seismic amplitude (correct)

Reservoir lithology

Band-limited nature of the seismic signal

Porosity changes in the reservoir

Which of the following is NOT discussed in the module?

Role of seismic inversion in exploration & production

Band-limited nature of the seismic signal

Typical processes in reservoir drilling (correct)

Applications of amplitudes in seismic interpretation

Why are seismic amplitudes widely used in qualitative interpretation?

To detect hydrocarbon anomalies Signup and view all the answers

What is an important aspect to consider regarding the seismic signal in the context of inversion problem?

The band-limited nature of the signal Signup and view all the answers

How can information contained in amplitudes be correlated with reservoir properties?

By detecting hydrocarbon anomalies, lithology changes, porosity changes, and fluid type Signup and view all the answers

What is the inverse problem in seismic reservoir characterization focused on?

Reconstruction of elastic parameters from seismic data Signup and view all the answers

What is the main reason that strict equality cannot be achieved in the inversion of observed wave fields?

Model only approximates the geological environment Signup and view all the answers

In seismic reservoir characterization, why is the solution to the inversion problem not unique?

Different models can generate the same wave field Signup and view all the answers

What determines the form of the operator L in seismic reservoir characterization?

Dimension (1D, 2D, 3D) and parameterization method of the model Signup and view all the answers

What does the seismic trace represent in a horizontally layered model with a normal incidence plane P-wave?

Convolution of a reflectivity trace and band-limited seismic wavelet Signup and view all the answers

What is one of the challenges with using a recursive inversion procedure as proposed by Lindseth for seismic reflection data?

Inability to recover P-impedance accurately Signup and view all the answers

What role does the band-limited seismic wavelet play in seismic trace inversion?

Acts as a filter cutting off low and high frequency components Signup and view all the answers

What is one issue with using equation (1) for recursive inversion proposed by Lindseth for seismic data?

<pre><code>ext{Recorded data does not match the reflectivity equation} </code></pre> Signup and view all the answers

"A Sonic log that has been converted to time has a very broad frequency bandwidth – one that extends from 0 to greater than 1 kHz." What characteristic of seismic signals does this statement refer to?

<pre><code>ext{Band-limited nature of seismic signals} </code></pre> Signup and view all the answers

Why is the seismic signal bandlimited?

Due to both the natural filtering effect of the earth and instrumentation limitations Signup and view all the answers

What happens to the low frequencies in seismic data according to the text?

They are lost by detector response or band-pass filtering circuits Signup and view all the answers

Why is it crucial to reconstruct low frequencies for seismic inversion?

To accurately capture the basic velocity structure for geologic interpretation Signup and view all the answers

What is the main limitation highlighted in the seismic inversion process due to bandlimited seismic traces?

Loss of both low and high frequency ends of the reflectivity spectrum Signup and view all the answers

Which type of inversion methods combine geostatistical modeling tools and forward seismic modeling?

Geostatistical inversion methods Signup and view all the answers

What is the purpose of using multiple realizations in geostatistical inversion methods?

To ensure stability and spatial coherence of the solution Signup and view all the answers

What distinguishes the Model Based and Sparse Spike inversion methods from Recursive inversion methods?

Objective function involving match between observed and synthetic seismic Signup and view all the answers

How does a seismic trace being bandlimited affect reflectivity spectrum at both low and high frequencies?

Results in missing low and high frequency ends of the reflectivity spectrum Signup and view all the answers

What is the main drawback of recursive seismic inversion techniques according to the text?

Bandlimited nature of the seismic trace leading to missing frequencies Signup and view all the answers

What role do objective functions play in modern seismic inversion techniques?

To control the match between observed and synthetic seismic data Signup and view all the answers

What is the purpose of seismic inversion in reservoir characterization?

To estimate critical reservoir properties like porosity and fluid saturation Signup and view all the answers

In seismic inversion, what information does the Vp/Vs ratio help estimate?

Shear velocity Signup and view all the answers

What technique utilizes converted PS wave data for additional information in the inversion process?

PP-PS Inversion Signup and view all the answers

For what purpose is the term 'AVA inversion' commonly used in seismic studies?

To calculate a set of elastic properties Signup and view all the answers

What is the main advantage of stochastic approaches in seismic inversion compared to deterministic methods?

They result in multiple realizations with the same probability Signup and view all the answers

Which application of seismic inversion involves assessing subsurface stability for potential geohazards?

Geohazard Assessment Signup and view all the answers

In what context would 4D seismic studies typically be applied?

Reservoir Management and Enhanced Oil Recovery Signup and view all the answers

What does joint PP-PS inversion require in addition to standard seismic data?

Converted PS wave data Signup and view all the answers

'Acoustic Impedance, Vp/Vs ratio, and density' are typically associated with which inversion process?

'Simultaneous Inversion' Signup and view all the answers

What aspect of seismic inversion is influenced by the set of available well and seismic data?

The choice of appropriate inversion methods Signup and view all the answers

What phenomenon in seismic data is described as interference occurring when the thickness of a target layer approaches half of the seismic wavelength?

Tuning effect Signup and view all the answers

In quantitative interpretation, what geostatistical method utilizes secondary data like Seismic Amplitudes to guide property estimation?

Collocated Cokriging Signup and view all the answers

What is one way to minimize the influence of overlying layers on amplitude readings in seismic data?

Transform seismic data into layer properties Signup and view all the answers

Why is it challenging to uniquely determine subsurface properties from seismic data alone?

Duality between layer thickness and properties Signup and view all the answers

What is a key factor affecting the reflection coefficient for a normal-incident P-wave at the interface between two half-spaces?

Impedance difference Signup and view all the answers

Which method can be used to estimate reservoir properties away from well locations based on known primary data?

Collocated Cokriging Signup and view all the answers

Why is a high correlation between primary and secondary parameters important in geostatistical methods for property estimation?

To guide property estimation accurately Signup and view all the answers

What does the duality between layer thickness and properties imply for seismic interpretation?

Difficulty in property differentiation Signup and view all the answers

'Additional data or constraints, such as well log data or rock physics models,' are often required to resolve ambiguities arising from what challenge in seismic interpretation?

'Impedance contrast' effects Signup and view all the answers

What is the main difference between the traditional seismic inversion approach and the method described in the text?

The traditional approach uses a physical model, while the described method identifies correlations between parameters. Signup and view all the answers

'The result of such estimation would be a Porosity map agreed with known values at wells locations' showcases the use of what method in property estimation?

'Geostatistical methods' application Signup and view all the answers

What is the primary use of the term related to inversion impedances developed from well logs?

To control frequencies below the seismic band width. Signup and view all the answers

Why is well to seismic tie considered essential in the seismic interpretation workflow?

To establish consistency between depth and time domains. Signup and view all the answers

What is the key purpose of wavelet estimation in the inversion process?

To determine reflectivity away from wells. Signup and view all the answers

Why do inversion methods aim to find a simple solution that matches seismic data and is consistent with well information?

To prevent instability in single-objective functions. Signup and view all the answers

What is a common input data requirement for all types of seismic inversion?

Structural interpretation Signup and view all the answers

How are well to seismic tie and wavelet estimation related in the inversion process?

They are both iterative processes performed multiple times. Signup and view all the answers

Why is it important to define optimal parameters before running the inversion?

To ensure convergence of the algorithm. Signup and view all the answers

What types of elastic properties are commonly obtained from the outcome of a seismic inversion process?

Acoustic impedance and shear impedance Signup and view all the answers

Why is quality control important at all stages of the inversion process?

To validate inversion results accuracy. Signup and view all the answers

What is the main purpose of seismic inversion in reservoir characterization?

To reconstruct low frequency components from seismic data Signup and view all the answers

What is the significance of seismic amplitudes in reservoir properties optimization?

They help in solving inverse problems related to seismic data Signup and view all the answers

Why is it essential to incorporate well data in seismic inversion procedures?

To improve the resolution of seismic images Signup and view all the answers

What role do modern algorithms play in seismic inversion?

Utilizing some form of an objective function for minimization Signup and view all the answers

How do seismic amplitudes aid in reservoir characterization?

By facilitating quantification of reservoir properties Signup and view all the answers