Not Sure if this is the exact answer. You need to have the velocity at well minimum for this workaround. I have seen it once from a collaboration between Geophysicist and Geomodeler. The Geophysicist have created the velocity from the sonic data at wells. The Geomodeler have distributed the velocity using the property distribution after building simple model and perform it using Kriging method.

Thank you dear Ali for sharing your experience.

The work flow for velocity modeling included Seismic and Well Data Loading, synthetic seismogram generation of key wells, QC (quality check) of seismic velocity cube and Time-Depth relationship (TDR) generated for different wells. The process also includes up-scaling of well velocity data into 3D Grid, sampling of seismic velocity cube into 3D Grid, creating Average Velocity property using well velocities as input and seismic velocity as guiding trend between wells. The Velocity model is created using average velocity property and converting time horizons into depth horizons using created velocity Model and QC.

Many thanks, Rajesh, for your answer.

I agree with @Rajesh..Before you can build a 3D, you must have gone through the process of Structural gridding, upscalling of well log property, Data Analysis which involves the varriogram, etc.

I have not tried using only checkshot but I think you should explore the steps in the image attached below to create your velocity log.

Or rather you should cross-plot the checkshot data and get an equation that you can imput into the log calculator to generate a velocity log (Make sure you use the PETREL velocity log template). Then you can imput the generated velocity log when creating your 3D Model.

Please make sure you compare and note that your output will depend on the the equation utilized for the transformation, the simulation method used to extrapolate the property and off course the number of well so available for the model.

I hope this helps.

Regards.

Dear Olatunbosun,

thank you for your answer.

Try this procedure if works, I got it from internet and used it once a long time ago (with small modification according to data I had)

https://www.scribd.com/doc/140514052/Build-a-3d-Velocity-Model-From-Checkshots-schlumberger-petrel

see attached file (downloaded from scribd.com - credit : Author / scribd.com)

Thank you Khurram for your answer. I already have tried and it works.

Dear all: the question How can I build a 3D velocity model using only checkshots in Petrel software? have a contradiction in itself. Let me explain:

as the same time, you are talking about "only checkshots", and therefore, it means that your database is made lone by wells. You do not use seismic!!!

Hence, if you do not use seismic, on focus, 3D seismic, using “only checkshots” you do not make a real 3D model, just a volume / volumetric model, but not a real 3D!!!

3D seismic data, by nature, is the only one tool to sample the subsurface in 3D.

Using exclusively well-logs means that your get lastly a volume, by any kind of interpolation, but not real 3D answer, due that wells, each of them, sample the subsurface only in 1D.

Think about it!!!

Cheers, Mario E. Sigismondi

Thank you Dr. Mario for your comment on the question.

I'd like to inform you that I have already constructed a 3D model from seismic data. This model represented the framework that was used for populating the velocity data of the checkshots. What is meant by "Only checkshots" is that velocity values were obtained from checkshots only and there wasn't any other source for velocity.

The checkshots were the only source for velocity.

Accordingly, the question has been modified.

Thanks again

Regards

Ahmed

Dear all,

thank you for your answers.

I'd like to inform you that the issue has been solved.

This can be done simply by upscaling the velocity values to the model scale (a previously constructed 3D structural framework). This is followed by running the petrophysical modeling process on the upscaled velocity.

The result will be a 3D velocity block.

Regards

Ahmed

Great my friend!

Dear Ahmed Abdelmaksoud thank you for reverting with the solution to the challenge you had. However, I am facing same challenge of having only velocity data from well. I don't really understand the your explanation on how to solve the problem. Can you elaborate a bit more?

Thanks.

Regards,

Courage

Dear Courage,

Please follow this processes

- MAKE A GRID: First, you to create a 3D structural grid which will be the base for your model (you will find this the process/model pane).

- PROPERTY UPSCALING: Here you have to upscale the well Log property (which in this case is VELOCITY), do some data analysis which involves a variogram.

- Generate a your velocity model just like you creating any Petrophysical Model (choose your preferred extrapolation method for the distribution of data from the data points accross the grid)

- Do some QC to validate your model

I hope this helps.

Regards

Olatunbosun Kafisanwo

Dear Courage Glorious

The elaborated answer has been provided by Olatunbosun Kafisanwo . In addition, if you do not want a 3D velocity block, if you just need a velocity model for converting your TWT maps into depth ones you can make it using another method.

Simply, in Petrel, open the advanced velocity model, then adjust the parameters of the window, after that, adjust the top and base of your velocity model with selecting the model as "V=V0=Vint" and "V0=Well TDR - Surface".

If you need further help, you can contact me.

Regards

Ahmed

Thank you Olatunbosun Kafisanwo and Ahmed Abdelmaksoud for your helpful responses, I will try them out and if I am stucked in any step I revert.

Regards,

Courage

Hi Ahmed Abdelmaksoud and Olatunbosun Kafisanwo I have been able to create a 3D velocity model via the processes you gave above, however I have found it difficult to use it for depth conversion. Please how do I do it? Also how can I depth convert fault sticks?

Thanks

Courage.

Ahmed Abdelmaksoud, could you please explain this part of your answer:

Simply, in Petrel, open the advanced velocity model, then adjust the parameters of the window, after that, adjust the top and base of your velocity model with selecting the model as "V=V0=Vint" and "V0=Well TDR - Surface".

I have only checkshots just like you did (please see attachment). From the checkshot data, what did you put as the surface and well top?

Dear @Abdul-Latif Benson Lamidi,

Your surface helps the model to define the zone/boundary in which the model should be limited to. In this case your surface is the top and base (time or depth) generated with the horizon you picked on seismic. Your well tops on the other hand, is those pointed picked on wells during well log interpretation and correlation. You should find this under (WELL TOP> STRATIGRAPHY). Note that, a zone has too surfaces(top and base) and also two well tops.

I hope this helps.

Olatunbosun Kafisanwo , thank you for the answer. Then what is the essence of the checkshots data if I use my interpreted horizon surfaces and well top data. But according to Ahmed, he built the velocity model only from checkshots data only and that’s what I only have. Ahmed Abdelmaksoud

Dear Abdul-Latif Benson Lamidi,

You need to input your surfaces and well tops in order to serve as foundation and boundary for the structural grid that will be utilized in the modeling process.

In @Ahmed Abdelmaksoud situation, the structural grid already exist so he was just trying to update an existing model.

I think you need to be more lucid about your major objective.

Regards.

Olatunbosun Kafisanwo after interpreting your horizons and faults from seismic cubes in time domain, how will you convert the horizons and faults to depth domain if you ONLY have checkshots to build the velocity model? Isn’t it possible to build a velocity model from only checkshots data with known SRD? I have no well tops. I have only checkshots and need a velocity model from it.

Dear all

Firstly, I'd like to share my answer to Courage Glorious about using the 3D velocity grid for depth conversion of surfaces and faults.

For using the 3D velocity model in time to depth conversion of either faults or surfaces, you can do as the following:

• Open the advanced velocity modelling in the seismic interpretation tab. As in the attached image, in the velocity modelling window (right), define the base and top of your upcoming velocity model.
• Select the model as average property, and drop the average velocity from the 3D grid that you have already constructed (left). Drop it in both the base and top of the model.
• After that, you will get a velocity model (not as a 3D block).
• Then, simply you can right click any fault or surface and select "depth conversion using active velocity model".

All the best

Secondly, for Abdul-Latif Benson Lamidi , you can simply do as in the attached image. But, adjust the top and base according to your model by values (as in the example) or by using surfaces. Adjusting the model for using "well TDR" will allow the velocity model to use your TDR or checkshots.

Hope it helps

Thank you dear Mubashar Shah

yara der deep research d start karhay d

Hello Ahmed Abdelmaksoud

Do you have a paper that discuss this equation

V=V0=Vint" and "V0=Well TDR - Surface".

regards

EL_mahdy

How can I fix the problem?

Dr. Munir Elmahdy

Not exactly. But you may check the paper of Al-Chalabi (1997) " Time-depth relationships for multilayer depth conversion", which has the different depth conversion methods. You may also check the following paper: " Vo-K method of depth conversion" by Marsden (1992).

Hope it helps.

Regards,

Ahmed

Hello Larasati Pinanjar Putri

You may try to remove the well tops and use constant numbers for the top and bottom of the velocity model.

Hope it works.

Regards,

Ahmed

Dear Dr. @Ahmed Abdelmaksoud please if that works with with you , can you send me steps ??

Hello M. Haggag

I have PDF that could help you

send me an email, and I will send it to you

regards

El-Mahdy

[email protected]

[email protected]

Dear Dr.@Munir Elmahdy

Thank you so much for your help I will connect with you via email

Hello Dr. M. Haggag

Hope you got what you need, from Dr. Munir.

All the best

Hi Dr.Ahmed Abdelmaksoud

Yeh, he contacted with me and sent me some useful papers

Thanks a lot for your concern

That's good.

All the best