Search found 38 matches

by jefry123
Fri Nov 20, 2020 12:13 pm
Forum: Oil and Gas Exploration
Topic: Flat and floating datum corrections, why and when?
Replies: 3
Views: 83

Re: Flat and floating datum corrections, why and when?

Thank you Guy, I learn a lot from your answers.

So, the smoother the topography, the more closer the two corrections using flat and float datums, right?

What should be the datum for the final output of the processing (stacks and gathers)?
by jefry123
Thu Nov 19, 2020 6:31 am
Forum: Oil and Gas Exploration
Topic: Flat and floating datum corrections, why and when?
Replies: 3
Views: 83

Flat and floating datum corrections, why and when?

Hi every body, I hope you all are safe and healthy in this Covid19 situation! I may have a problem in understanding the application of flat and floating datum corrections in seismic data processing. I know that, we use the flat datum correction because the hyperbolic assumption is true if sources an...
by jefry123
Thu Jun 11, 2020 5:38 am
Forum: Oil and Gas Exploration
Topic: Marine seismic data acquisition
Replies: 1
Views: 801

Marine seismic data acquisition

What is the difference between conventional marine seismic data acquisition and High Resolution marine seismic data acquisition? I realized that there is a P-cable acquisition which is categorized as HR acquisition, but, in this kind of acquisition the streamer length is only up to tens of meters. D...
by jefry123
Fri May 29, 2020 3:44 am
Forum: Oil and Gas Exploration
Topic: Offset class determination for imaging
Replies: 5
Views: 1110

Re: Offset class determination for imaging

Thank you, that was the thing I was trying to understand. How about in 3D surveys? Is it different in land and marine?!
by jefry123
Thu May 28, 2020 4:13 am
Forum: Oil and Gas Exploration
Topic: Offset class determination for imaging
Replies: 5
Views: 1110

Re: Offset class determination for imaging

Thank you,
In some documents there are some rule of thumbs, as two time the shot intervals or somethings like this. How do these things work?
by jefry123
Tue May 26, 2020 3:33 pm
Forum: Oil and Gas Exploration
Topic: Offset class determination for imaging
Replies: 5
Views: 1110

Offset class determination for imaging

Before applying pre-stack migration, we creates offset classes to have regular folds to reduce migration artifacts. For 2D they are common offset gathers and for 3D they are common offset vectors, Right?

And, How do we calculate the offset range/interval for offset class creation?
by jefry123
Sun Mar 22, 2020 8:30 am
Forum: Oil and Gas Exploration
Topic: Statics corrections in reflection seismic processing
Replies: 12
Views: 6895

Re: Statics corrections in reflection seismic processing

The way I think of this is that we want to simulate the seismic survey being collected on a flat, horizontal surface,so the reflections make pretty hyperbolas. ..... Thank you so much Guy, you always explains every thing in the easiest way which is great. I still have a little problem in differenti...
by jefry123
Tue Mar 17, 2020 7:20 am
Forum: Oil and Gas Exploration
Topic: Statics corrections in reflection seismic processing
Replies: 12
Views: 6895

Statics corrections in reflection seismic processing

I have problems understanding statics correction for reflection seismic processing. In this Covid-19 situation and home staying days, I thought it may be a good time to ask my questions and have a chance to have your explanations. Actually, I am going to write down what I realized and some questions...
by jefry123
Fri Nov 15, 2019 1:27 pm
Forum: Oil and Gas Exploration
Topic: Anisotripic pre-stack time migration
Replies: 1
Views: 3065

Anisotripic pre-stack time migration

hello, I would like to know the difference between "anisotropic PSTM" and "curved-ray PSTM". Is there any difference between these two? In anisotropic PSDM, the interval velocity field is updated using the delta value, do we update RMS velocity in anisotropic PSTM or only PSTM gathers are flatten (s...
by jefry123
Fri Nov 08, 2019 4:08 am
Forum: Oil and Gas Exploration
Topic: Marine and Land data multiple attenuation
Replies: 3
Views: 3314

Re: Marine and Land data multiple attenuation

Thank you for your complete answer as always Guy. The reason for my general question is that you can see a lot of new methods or categorizations for multiple attenuation in literature. I wanted a general categorization in which marine and land data applications be possible. for example, I know that ...
by jefry123
Tue Nov 05, 2019 12:42 pm
Forum: Oil and Gas Exploration
Topic: Marine and Land data multiple attenuation
Replies: 3
Views: 3314

Marine and Land data multiple attenuation

Hey guys,

I would like to know what methods and approaches can be used to attenuate multiple reflections in marine and land seismic data respectively?
Thank you in advance.
by jefry123
Fri May 24, 2019 8:49 am
Forum: Oil and Gas Exploration
Topic: Oceab Bottom Cable Processing
Replies: 0
Views: 3073

Oceab Bottom Cable Processing

Hi everyone,

I am looking for a general processing sequence for OBC data and its differences with marine acquisition processing sequence?

Thank you
by jefry123
Fri Jan 11, 2019 5:23 am
Forum: Oil and Gas Exploration
Topic: Post-Processing on Common Image Gathers
Replies: 1
Views: 3278

Post-Processing on Common Image Gathers

What post-processing do you suggest for migration output gathers? These gathers are going to be used for AVO analysis.
by jefry123
Thu Dec 06, 2018 3:16 pm
Forum: Oil and Gas Exploration
Topic: PSDM and PSTM mistie correction
Replies: 0
Views: 3152

PSDM and PSTM mistie correction

Hi you all, I hope everything's fine with you. I have some questions and hope you could help me with them. - When we do PSTM and obtain our final Stack Sections, we try to correct misties between different lines and also with well data. right? - When I do PSDM on the same CMP gathers used for PSTM, ...
by jefry123
Fri Sep 14, 2018 9:08 am
Forum: Oil and Gas Exploration
Topic: Different seismic datums, their difference
Replies: 6
Views: 2905

Re: Different seismic datums, their difference

Thank you for your complete reply.
One more thing, Can we know the datum type according to the data (gathers or section)? For example, if they are all started from the same time or depth or something like that?
by jefry123
Thu Sep 13, 2018 10:29 am
Forum: Oil and Gas Exploration
Topic: Different seismic datums, their difference
Replies: 6
Views: 2905

Different seismic datums, their difference

What is the difference between fix datum, floating datum, SRD and flat datum?!

Our data is on which?
And, What happens to the data if transformed to each of them?!

What datum do we use for PSTM and PSDM?
by jefry123
Sun Sep 09, 2018 10:32 am
Forum: Oil and Gas Exploration
Topic: PSDM for multi lines
Replies: 0
Views: 1067

PSDM for multi lines

How do you perform Pre-Stack Depth Migration when you have multi lines? I think doing it for each line separately would be a difficult task. However, for having a somehow automatic approach, we should have an interval velocity for all lines, am I correct? or at least, we cannot use a layer-based app...
by jefry123
Fri Aug 31, 2018 9:46 am
Forum: Oil and Gas Exploration
Topic: PSDM parameters estimation
Replies: 0
Views: 1027

PSDM parameters estimation

How do we select and estimate aperture for Pre-Stack Depth Migration (PSDM)? Is there any rule of thumb?

And, How do we decide about tomography X (CRPs,meter) and Z (meter) parameters in different iterations?
by jefry123
Fri Aug 10, 2018 1:42 pm
Forum: Oil and Gas Exploration
Topic: Appropriate Initial Interval Velocity for PSDM
Replies: 0
Views: 1786

Appropriate Initial Interval Velocity for PSDM

We know that Pre-Stack Depth Migration (PSDM) results in a better image of the subsurface in relative to PSTM, specially in a more complex one. However, the quality of this image highly depends on the accuracy of the interval velocity model. As I know, there are two ways for building an initial inte...
by jefry123
Fri Apr 13, 2018 5:02 am
Forum: Oil and Gas Exploration
Topic: With what do we compare the PSDM results?
Replies: 1
Views: 989

With what do we compare the PSDM results?

I am working on Pre-stack Depth migration. As I know, depth imaging has some benefits over time imaging for example better imaging in complex areas, obtaining an interval velocity model and since its output is in depth domain, no need of time to depth conversion. However, as in the term "better imag...
by jefry123
Fri Mar 02, 2018 12:17 pm
Forum: Oil and Gas Exploration
Topic: pre-stack time migration, a misunderstanding
Replies: 0
Views: 1328

pre-stack time migration, a misunderstanding

I am dealing with prestack time and depth migrations. There are some ambiguities which I hope to understand step by step. I would be grateful if you could help me with this. Somewhere I read that "it is a misconception that people think PSTM is done in time domain and PSDM in depth domain, while bot...
by jefry123
Tue Feb 13, 2018 12:50 pm
Forum: Oil and Gas Exploration
Topic: Pre-stack depth migration theory
Replies: 1
Views: 1143

Pre-stack depth migration theory

I am looking for the basic theory of pre-stack depth migration. I have found some materials about pre-stack time migration (about how it uses the DSR equation to find the travel times and sum it to the apex, scatter point) but I could not find some thing to help me understand the PSDM basics. I appr...
by jefry123
Mon Feb 12, 2018 1:56 pm
Forum: Oil and Gas Exploration
Topic: Synthetic model for PSDM
Replies: 9
Views: 2542

Re: Synthetic model for PSDM

Thank you for your suggestion.
Apparently the software I was using for the forward modelling do not take into account the anisotopic parameters in demo mode (despite that it asks me to import the thomson parameters!). Do you know any other software I could use?
by jefry123
Sun Feb 11, 2018 4:05 am
Forum: Oil and Gas Exploration
Topic: Synthetic model for PSDM
Replies: 9
Views: 2542

Re: Synthetic model for PSDM

Yes, I am going to show that in some cases of geological structures anisotropic PSDM is a better tool than the isotropic PSDM.