Forums/Announcements
Release of Tsunami A2011
Jaclyn Cribley
posted this on March 30, 2011 15:14
A2011 Release Notes
We thank you for your continued use of our software and support in making the Tsunami Suite better. Special thanks go out to our customers who have worked with us to add the most wanted features. Feedback and requests from our users are what drive our continued improvement.
This release contains enhancements to Pre-Stack Depth Migration and Ray Tracer. We have long supported VTI anisotropy; and now the Tsunami suite allows you to use TTI in ray calculation. The Pre-Stack Depth Migration application can directly prepare data for migration.
To get updates on planned changes and releases of our software, please visit our new support portal for the latest information ( http://support.tsunamidevelopment.com/ ). Do not hesitate to call us, or email our customer support team any time at support@tsunamidevelopment.com .
The Information contained in this document is subject to change without notice. Tsunami Development assumes no responsibility for any error that may appear in this manual. Tsunami Development does not warrant that this document is error free. Please report any errors in this document in writing to Tsunami Development. Some states or jurisdictions do not allow disclaimer of expressed or implied warranties in certain transactions; therefore this statement may not apply.
Overview
The A2011 Tsunami Suite releases an enhanced Pre-Stack Depth Migration 5.8. We now include a Data Prep tab which allows you to prepare your data for migration directly in PSDM. With this release you can now scale and filter trace data before running migration; this feature will also be added to Pre-Stack Time Migration in the next release. An enhanced Ray Tracer 5.8 is also included in this release which allows tilted transverse isotropy (TTI) to be incorporated in the calculation of the travel times.
We have made fixes to Ray Tracer, Smooth Velocity 5.7, and Pre-Stack Time Migration 5.8. Pre-Stack Depth Migration’s Geometry Map now allows for display of very large datasets.
We also updated how the GUI stores user profile information for recently viewed parameter files and the last opened directory.
New Features
Pre-Stack Depth Migration 5.8
Tsunami releases Data Prep in Pre-Stack Depth Migration 5.8 so our clients can prepare their data for migrations directly in PSDM. With this release you can now scale and filter trace data before migration.
Data prep
Select Pre-Stack Depth Migration > Data Prep to apply the following parameters:
•Amplitude Scaling computes and applies a time variant scaling function defined by a 1/t scaling power. For example, enter a parameter value of 2 to scale the input trace by 
•Filters applies a Bandpass frequency filter defined by low cut/high cut frequency pairs. Enter values for zero pass frequency and full pass frequency to define the high cut and low cut ramps.
•AGC automatically applies an AGC operator length defined by the Window Length parameter.
Ray Tracer 5.8
TTI anisotropy can now be incorporated in the calculation of the travel times in Ray Tracer by supplying azimuth and dip files to the input parameters.
Support for TTI
The observed phenomenon of waves traveling at different speeds through the earth, depending on their direction of propagation, is known as Seismic Anisotropy. This effect can be caused by geological factors such as layering, fracturing, tilting, etc. When layers are relatively flat and the principal cause of anisotropy is fine layering, such as that commonly found in shales, the medium is said to be Vertically Transversely Isotropic, or VTI. In this case, the wave travel times vary between the purely vertical and purely horizontal directions. The anisotropic parameters epsilon and delta describe this relationship between horizontal and vertical velocities, and are used as additional input to the imaging software. This assumption works well for imaging in many settings.
When structural deformation has occurred, and the anisotropic layers are no longer horizontal, other factors must be included in order to perform accurate imaging. These cases are known as Tilted Transverse Isotropy, or TTI. In addition to the anisotropic parameters epsilon and delta, dip and azimuth information must also be input to the imaging software in order to describe the structure. This can become particularly important in structurally complex areas such as overthrust zones. If TTI imaging is not performed in areas such as this, vertical and/or lateral mispositioning of events may occur.
The following files are all required for TTI:
Provide an epsilon SEG-Y file. The file must contain epsilon values at the same inline, xline and depth as the velocity samples in the velocity model.
Example: /projects/summit/epsilon.sgy
Provide a delta SEG-Y file. The file must contain delta values at the same inline, xline and depth as the velocity samples in the velocity model.
Example: /projects/summit /delta.sgy
Provide an azimuth SEG-Y file. The file must contain azimuth values at the same inline, xline and depth as the velocity samples in the velocity model.
Example: /projects/summit /azmiths.sgy
Provide a dip SEG-Y file. The file must contain delta values at the same inline, xline and depth as the velocity samples in the velocity model.
Example: /projects/summit /dip.sgy
Fixes and/or Changes
General
Recently viewed parameter files and the last opened directory information are stored in a hidden .tsunami file. The application previously wrote the .tsunami file to the directory from which the GUI was launched. When another user launched the GUI from the same directory, errors occurred because preferences from the previous user were used for the second user if permissions for the .tsunami file were closed. The .tsunami file is now stored in each user’s home directory to avoid these problems.
Pre-Stack Time Migration 5.8
Incorrect log file messages
Clients reported that PSTM would not read GCI data and received a log file report error #51:
WARNING: CDP X,Y byte locations not specified
Outputting CDP X byte 213 CDPY byte 217
Opening trace input file /hds21/gci/BeauregardPa_SW.PSDM1.gathinp2.GCId.1
ERROR #51: Invalid number of samples read from trace header
check byte location
Remove tmp file
Job aborting, got signal -1
Job aborting, got signal -1
Error code 0
The problem was that CDPX and CDPY were put in bytes 209 and 213 when an input byte location was not specified. Byte 209 is the default for the Migration distance. This is now fixed and CDPX and CDPY are in bytes 213 and 217 whenever an input byte location is not specified.
