[OpendTect_Users] Balancing of surveys.

[Arnaud Huck]

Dear Gholam,

3D shifts extraction and application are performed using the matchdelta
and deltaresample attributes respectively. In your application for
instance the "Reference cube" is the near stack, the "Match cube" are
mid and far for the first matchdelta attribute(s). This attribute
defines 3D volumes containing shifts in ms or meters/feet. I do
recommend to filter however the shifts before applying them for shifting
the volumes, using a dip-steered median filter with a large stepout (at
least 4).
The application is done by providing the mid or far volume as "Input
cube" and the previously defined (and possibly filtered) shift
attribute, or cube if pre-computed.

Phase shift is more difficult to tackle. I would advise to take care of
the phase difference before computing and applying the shifts, since the
algorithm will look for the seismic events position. You can do this
using the phase rotation attribute defined in the "evaluate attributes"
default attribute set.

The worfklow is not limited by the kind of input data. If fits partial
stacks and/or different surveys as long as they share the same grid.
Spectral balancing would best be performed using seismic spectral
blueing (http://www.dgbes.com/index.php/seismic-spectral-blueing.html).
This workflow matches the seismic spectrum to the well reflectivity
spectrum. You may apply the workflow for all partial stack volumes in
such way that the mapping is performed over the same bandwidth. As a
consequence the output volumes will have equalized bandwidth, honouring
in addition the well reflectivity data.

Best regards,
Arnaud Huck.

-- dGB Earth Sciences
-- Nijverheidstraat 11-2, 7511 JM Enschede, The Netherlands
-- mailto: arnaud.huck at dgbes.com, http://www.dgbes.com
-- Tel: +31 53 4315155 , Fax: +31 53 4315104


On 03/19/2010 10:52 AM, Gholam Reza Ahmadi wrote:
> Dear All,
> I am wondering if anybody knows if/how the following two issues are possible to perform in OpendTect.
>
>
> 1: Offset balancing of surveys.
> Given a Near/Mid/far offset lines(Cubes in 3D case) is it possible (using OD) to do the following:
> Holding the near offset as reference then perform Spectral balancing, Time shift alignment (Mid and far to Near) and Phase shift (Mid and Far compared to Near)
>
>
> 2: Balancing of surveys (Mainly 2D but also 3D)
> Given a reference survey (Full offset), Do the Spectral balancing, Time shift and Phase (as in point 1) for different (full offset) surveys
>
> Reza
>
> Best regards,
> G. Reza Ahmadi |  Exploration Specialist
> INT GEX EMEA
> ________________________________
>
>
> StatoilHydro ASA
> Post box 910, NO-9481  Harstad
> Telephone:
> + 47 99 58 16 29
> E-mail:
> gra at statoilhydro.com
> Visitor address:
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> www.statoilhydro.com
>
> -----Original Message-----
> From: users-bounces at opendtect.org [mailto:users-bounces at opendtect.org] On Behalf Of Bert Bril
> Sent: 19. februar 2010 10:40
> To: Users at opendtect.org
> Subject: [OpendTect_Users] Command Driver (Working with several wells)
>
> Hi all,
>
>
> Emilson wrote:
>
>   
>> After setting up well tracks and depth models for dozens of wells,
>> I'd like to know if there is a way to load the associated logs at
>> once, maybe using a script or batch processing file.
>>     
> We do get requests about a utility to load many wells in one go. Until
> now, we haven't made it. The considerations are:
> * Making such a utility is very hard
> * In most cases the variability between different the input files is
> enormous
> * There is a commercial plugin loading from commercial data stores
> We have had this on our 'wish-list' for a long long time, but there are
> always higher priorities.
>
>
> And, there now is a tool inside OpendTect that can help you automate
> recurring, similar tasks: the 'Command Driver' (utilities-Tools-Command
> Driver). We made it for automated testing, but it is now used by the
> case studies people here in dGB as well for exactly things like loading
> a lot of wells, horizons, and so forth.
>
> The scripts are rather easy to understand. They are in terms of the
> items you see in the dialogs. A 'command recorder' is present that can
> capture actions and write those into a Command Driver script. Not every
> possible action is caught, but every 'normal' series of dialog-, tree-,
> icon- and menu-actions do work.
>
> An example of such a script (just recorded this) where I actually loaded
> some logs:
>
>
> dTect V4.1
> OpendTect commands
> Fri Feb 19 10:02:12 2010
> !
>
> [OpendTect Main Window]
> Menu "Survey`Import`Wells`Ascii`Logs"
>
> [Well file management]
> Button "Import"
>
> [Logs]
> Button "Select Input (pseudo-)LAS logs file"
>
> [Open]
> FileOk "/d44/bert/surveys/F3_Demo/Rawdata/tst.las"
>
> [Logs]
> Button "TVDSS" On
> Button "Ok"
>
>
> To load a whole series of logs, you'd have to repeat the last set of
> commands for each of the LAS files. This particular example would load
> all logs in the LAS file. Say don't want that; then you can add things like:
>
> ListClick "Select logs" "Density_Final2 (Density)" Left
> ListClick "Select logs" "Porosity_1 (Porosity)" CtrlLeft
>
> ... before the 'Button "Ok"'. And so forth. You will understand the
> problems making the 'load all' utility if you have LAS files where the
> logs have different names, or are not present, or ...
>
> Lastly, there are some 'autoexecute' options:
> * If you place an 'autoexec.cmd' script in the 'Proc' directory of the
> survey, it will be executed at startup or when you select the survey.
> * You can specify a command file to run after startup. In this way the
> whole OpendTect can be run in a sort of 'batch mode' if you want to. For
> that, specify 'cmd=the_full_filename' on the start_dtect command line
> (on Windows you need to make a batch file).
>
> More info in the manual:
> http://opendtect.org/rel4/doc/User/base/command_driver_manual.htm
>
>
>
> Bert Bril
>
> --
> -- Bert Bril / OpendTect developer at dGB
> -- mailto:Bert.Bril at opendtect.org , http://opendtect.org
>
>
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