[OpendTect_Developers] Get seismic in well position

[Bert Bril]

Hi all,


Fernando wrote:

> Hi, I'm developing a wavelet extraction plugin based on well logs and
> seismic amplitude, so I need to collect the nearest trace to the well
> track. My track is vertical.

So basically there is one position in which you need a trace. The 
nearest BinID is always given by SI():

const BinID nearbid( SI().transform(wellcoord) );

You can make a SelData out ouf it, or use:

reader.seisTranslator()->goTo( nearbid );

Things get a lot worse when your track is not (guaranteed) vertical. The 
extraction may cover several traces, see for example the code for the 
'Create attribute log' (start with uiWellAttrib/uicreateattriblogdlg.cc).


> I was thinking in creating a SelData by computing a small square of
> traces (say 3x3 or 4x4) that I expect to be at the well position. Then I
> would get the traces by a SeisTrcReader limited by this SelData. With
> the SeisTrcInfos in hand I cal get the coordinates and calculate the one
> that is the nearest to the well coordinates. There are any other ways to
> do it?

Your method seems OK, and it allows you to do a search for the 'best' 
trace for your particular purpose. If you can line up the traces you may 
also want to stack them (if you can afford the price in terms of 
frequency content).


/Bert

-- 
-- Bert Bril / OpendTect developer at dGB
-- mailto:Bert.Bril at opendtect.org , http://opendtect.org