[OpendTect_Users] creating usable wavelet for deterministic inversion

[Arnaud Huck]

  Dear OpendTect users,

Obtaining the best wavelet to use during the deterministic inversion is 
the final step of the well-to-seismic tie procedure. This latter can be 
considered as a job on its own, therefore I will only present to major 
guidelines to be followed:

1- Load your wells using checkshot data if available or already 
optimized time-depth model(s).

2- Generate the wavelet to be used for the synthetic-to-seismic ties; 
Most people use a statistical wavelet extracted from the seismic data. 
The alternative would be to use a synthetic Ricker wavelet. Both can be 
created from the wavelet manager.

3- Tie your wells using the initial wavelet. Remember that you can fill 
the holes and extend the input logs from the wells manager ("Create" 
button). Missing (density) logs can also be created there. Wells are 
tied by picking on the synthetic and composite seismic traces. A single 
pick will apply a bulk shift, more will stretch and squeeze. Pressing OK 
will save the new time-depth curve as the active time-depth curve for 
the well. Nevertheless before doing this you need to save the 
deterministic wavelet extracted during the tie for the active well. Its 
parameters are set in the "Display additional information" window: The 
deterministic wavelet can get another window length, phase rotation and 
taper before being saved. The extraction window is the correlation 
window. Once the estimated wavelet is finalized you can save it by 
pressing the save button in the main tie window.

4- Repeat step 3- for all wells.

5- Once you have generated one deterministic wavelet per well, you can 
merge them from the wavelet manager in order to obtain the composite 
wavelet. The merge is nothing more than a stack, with optional alignment 
and normalization parameters. The merge function is currently available 
only in the development release 4.1. This composite wavelet should be 
the "best" wavelet to use during deterministic inversion. Please note 
that most experts would advise you to merge at least wavelets from 10 
wells in order to get a stable composite wavelet.

Best regards,
Arnaud Huck.

-- Senior Geoscientist
-- 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 08/31/2010 01:59 PM, Dele Falebita wrote:
> Pls guide me through how obtaining the best wavelet to use during
> deterministic inversion.
>
> Thanks
>