dirack / crevelocityinversion Goto Github PK

Documentation request

Describe your documentation request clearly bellow

Program version

What kind of documentation you are requesting?

• README files.
• Wiki pages.
• Jupyter notebooks.
• Other

🐛 Bug report

Describe the bug

Diffraction simulation is not working, the simulated hyperbolas are not generated correctly. It appears a black hyperbola in the stacked section, instead of the simulated hyperbola.

To Reproduce
Steps to reproduce the behavior:

1. Run the Velocity inversion experiment with the following data

section.tar.gz

sfin st.rsf 
st.rsf:
    in="stdin"
    esize=4 type=float form=native 
    n1=600         d1=0.004       o1=0.3        label1="Time" unit1="s" 
    n2=201         d2=0.025       o2=0          label2="CMP" unit2="Km" 
    n3=1           d3=0.025       o3=0          label3="CMP" unit3="Km" 
	120600 elements 482400 bytes

2. With this version of the diffraction simulation program https://github.com/Dirack/diffractionSimulator/tree/0271f0098a218367a35a921a8fbcf52e4613c7ae sfdiffsim.

3. The simulated hyperbolas will appear as the black image showed previously.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Linux Ubuntu
• Version 19.04 Focal Fossa

Additional context

Documentation request

Describe your documentation request clearly bellow

Diagrams of the package that will be produced showing the way it uses dependencies and connection between the packages.

Program version

None. This is the first version.

What kind of documentation you are requesting?

• README files.
• Wiki pages.
• Jupyter notebooks.
• Other (Diagrams of the package)

🎉 Feature request

Is your feature request related to a problem? Please describe.

Scratch a SConstruct to do a velocity inversion using diffraction simulated hyperbolas in the stacked section and diffraction
migration by focusing analysis

Describe the solution you'd like

Do the conventional NMO stacking using the functions of MadagascarRecipes package, 'kimodel.py' and 'velocityAnalysis.py' to obtain the stacked section. Run iterative picking to get (m0,t0) pairs of a reflector in the stacked section. Simulate diffraction hyperbolas and migrate it using focusing analysis.

🎉 Feature request

Is your feature request related to a problem? Please describe.

Use cubic spline functions to represent the velocity model variation in depth to allow models with lateral velocity variations.

Describe the solution you'd like

Use cubic spline functions of the velocity

Describe alternatives you've considered

You could split the velocity model in stripes and define a cubic spline velocity function of depth to each stripe.

Additional context

Generate a study about velocity mode update using one interface model. This model is updated in a loop and interface is represented by a set of nodes of a spline cubic curve. In each iteration of the loop this nodes are disturbed and interpolated.

The purpose of this experiment is to produce a way of model searching updating the model and checking the coherence between the seismic data generated with this model in comparison with initial model

Originally posted by @Dirack in #2 (comment)

🎉 Feature request

Is your feature request related to a problem? Please describe.

This algorithm estimates the velocity model, depth domain, using time migration velocities. As an intermediate step, it estimates the Dix velocity from interval velocities and geometrical spreading of the image ray.

Describe the solution you'd like

Obtain the time migration velocity using a focusing migration algorithm through diffraction hyperbola simulation, and use this as input to the Cameron algorithm.

Additional context

• Use this references:
  • time_depth_conversion.pdf
  • camerom.pdf

🎉 Feature request

Is your feature request related to a problem? Please describe.

The ray tracer should receive the RNIP and BETA parameters in order to determine CRE traveltime curve. From NIP point, two reflection rays are traced with angle TETA in relation to the normal determined by the normal ray that reaches NIP. Both rays should reach the acquisition surface.

After that, CMP and Offset coordinates are calculated and the time misfit is given by the difference between the CRE traveltime calculated and the sum of the traveltimes between these two reflection rays.

Describe the solution you'd like
A clear and concise description of what you want to happen.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

🎉 Feature request

Is your feature request related to a problem? Please describe.

Calculate the data misfit of the rays traveltimes in a constant velocity model in comparison with the true model (constant velocity model too).

Describe the solution you'd like

Build a traveltime curve for a constant velocity model. Trace rays with the program niptimecurve and get the data misfit between then.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

🎉 Feature request

Is your feature request related to a problem? Please describe.

No.

Describe the solution you'd like

Use a spline cubic function to represent velocity model varying with depth.

Describe alternatives you've considered

Additional context

In this repository there is a study about the cubic spline functions

🎉 Feature request

Is your feature request related to a problem? Please describe.

No.

Describe the solution you'd like

The program sfstereoniptomo should use a constant velocity gradient model to fit the data in the velocity inversion algorithm.

Describe alternatives you've considered

The parameter optimized in Very Fast Simulated Annealing (VFSA) step is the velocity gradient of the model. VFSA will optimize this parameter in a loop.

Additional context

It should use the following equation to generate the model:

v(z) = v0 + grad * z

This equation describes a velocity varying with depth model (example of this model in the image bellow).

🎉 Feature request

Is your feature request related to a problem? Please describe.

Create programs to set up the model and to get traveltime curves for each NIP sources to be used in NIP tomography

Describe the solution you'd like

That will be accomplished by two programs:

• A program to set up model: Trace normal rays from acquisition surface into the model to get NIP sources position.
• A program to get traveltime curves: Trace several rays from NIP sources to acquisition surface.

Describe alternatives you've considered

Modify the Madagascar program sfrays2, used to kinematic ray tracing, to create new programs.

Additional context

• Example of a exploding source point. Several rays are traced from source to acquisition surface using Madagascar program sfrays2:

• Example of a ray traced from acquisition surface into the model using sfrays2: