51 Questions
What is the first step in the inversion preparation process?
Understanding the relationship between seismic data times and well borehole depths
What is the purpose of Well-to-seismic tie in the seismic inversion workflow?
Establishing a reliable time to depth conversion for seismic data interpretation
Why is Well-to-seismic tie important for deterministic wavelet extraction in the inversion workflow?
To rely on a good well-seismic match for stable inversion wavelets
What type of data do checkshot surveys provide in the seismic inversion workflow?
Velocity of seismic waves at various depths along the borehole
In the Well-to-seismic tie process, what is involved in generating a set of Depth-Time curves?
Correlating well depths to Seismic times for each well
What role does the relationship between seismic data times and well borehole depths play in the seismic inversion workflow?
Understanding the time to depth conversion for seismic data interpretation
What type of information do VSP surveys provide directly beneath the wellbore?
High-resolution seismic information
What must be done before running sonic logging tools in a well?
Casing the loose near surface rocks
Why may the sonic log not perfectly match the seismic data?
The first layer velocity is unknown
What is extracted from the seismic data for the procedure of well-seismic tie?
Zero-phase statistical wavelet
What is computed by convolution of reflectivities with a zero-phase statistical wavelet in the well-seismic tie procedure?
Synthetic seismograms
What do global time shifts aim to improve in the well-seismic tie procedure?
Match with seismic data
Why is it important to consider elastic log quality in the well-seismic tie analysis?
A petrophysical revision before inversion study
What does the check shot correction aim to adapt to match surface seismic data?
Log time-depth curve
What is done with the drift curve during the check shot correction process?
It is interpolated to measure discrepancies
What does a zero offset synthetic trace typically consider?
The full stack or near-offset partial angle stack
What is the purpose of statistical wavelets extracted from seismic stacks?
To provide average seismic character in terms of amplitude and frequency spectrum
In the context of calibration, what is done if a residual time shift is detected between synthetic and seismic traces?
Apply the detected time shift to maximize the correlation
What should be done to improve the correlation in the 'Calibration / Stretch and Squeeze' step?
Stretch or squeeze the time-depth curve
Why is it important to limit the number of tie points in the 'Calibration / Stretch and Squeeze' step?
To prevent introducing a phase shift to the synthetic
What is a potential solution if large differences are observed between original and calibrated sonic logs?
Identify and remove bad points
What is the key principle when estimating phase shifts in seismic data?
Use different intervals for consistency checks
In the context of statistical wavelet extraction, what does a spectral analysis of the seismic provide?
Information on stationarity of the seismic signal
What is the main purpose of extracting statistical wavelets from seismic stacks?
Give average seismic character in terms of amplitude and frequency spectrum
In wavelet extraction, why should the analysis window be greater than twice the wavelet length?
To capture low-frequency information
What can be done if there are large differences between two sonic logs during calibration?
Check input information for possible errors
What is the main benefit of using the Roy White Algorithm for wavelet estimation?
Produces a series of diagnostic parameters to estimate reliability
In deterministic wavelet extraction, when is the Full Wavelet method typically used?
When several good events for correlation are available
What does the Proportion of Energy Predicted (PEP) measure in wavelet estimation?
Total energy in the seismic trace that can be predicted from well log reflectivity
Why is it recommended to extract single wavelets at each well during quality control?
To ensure the wavelets have similar phase and amplitude spectrum
What is the main difference between the Full Wavelet method and the Constant Phase method in deterministic wavelet estimation?
The Constant Phase method approximates phase as a constant value
What range does the Root Mean Square Error (RMSE) value typically fall into for an accurate wavelet?
0.0 - 0.5
What is the primary advantage of the Constant Phase method over the Full Wavelet method in wavelet estimation?
It is more robust when logs do not tie well with seismic data
How is the amplitude and phase of the deterministic wavelet estimated in Roy White Algorithm?
Through cross-coherence analysis between seismic and synthetic reflectivity
'Given that tie location, determine the optimal wavelet.' Which step of the methodology does this statement refer to?
'Extracting the wavelet using well log data'
Why is it recommended to use multiple wells within a survey and the Multi-well (average) wavelet?
To generate stable inversion wavelets by comparing different well wavelets
Why is it critical to have a wavelet size that can describe frequencies down to 5Hz?
To prevent unstable results in the low-frequency range
What does it indicate if the phase spectra of a wavelet is not flat?
There is a mis-tie between the well and seismic data
Why does the inversion workflow rely on a good well-to-seismic match?
To ensure that the wavelet extraction is stable
What is the purpose of subjecting all extracted wavelets to Quality Control?
To compare between different wells and stacks
What is the significance of defining the correct wavelet scaling in the inversion process?
It enables accurate retrieval of reflectivity from inversion
Why is it important to know the phase and polarity of the seismic wavelet?
To correctly interpret seismic data by filtering through the wavelet
What is one of the pitfalls associated with synthetic seismograms mentioned in the text?
Failure to account for wavefront dispersion and absorption effects
What is a key difference between synthetic seismograms and actual seismic data mentioned in the text?
Synthetic seismograms involve only zero-offset traces
What is the general problem with wavelet extraction discussed in the text?
Issues with phase shifts and frequency content changes
Which approach uses both seismic data and wells to estimate the wavelet?
Deterministic estimation
What is involved in maximizing the match between wells and seismic during deterministic wavelet extraction?
Determining the seismic reflectivity convolutional operator
Why is the knowledge of the seismic wavelet crucial for interpreting seismic data?
To ensure the phase and polarity are correctly matched in the data
What must be done before extracting a deterministic wavelet using logs according to the text?
"Calibrate wells properly"
What strategy is recommended to address the 'chicken-and-egg' issue related to wavelet extraction according to the text?
Use zero-phase statistical wavelet for calibration
What does deterministic wavelet extraction aim to achieve according to the text?
Maximizing the match between well reflectivities and seismic data
Learn about interpreting seismic synthetics and common pitfalls in seismology. Understand the importance of clear variations in the correlation function and ways to avoid inaccuracies in well synthetics. Explore potential errors when matching events without check shots.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
