Using GLOBE Claritas 2D/3D Seismic Processing Software June 2008 - - PowerPoint PPT Presentation

Using GLOBE Claritas™

2D/3D Seismic Processing Software June 2008

www.globeclaritas.com

• Created as a processing environment
• Designed to fit around your workflows and practices
• No un-wieldy database or forced data structures
• Simple ASCII text or modified SEGY file formats
• Easily linked to third party software
• Designed to support code and methodology development
• Flexible : handles data from GPR to earthquake scale
• Site licensed : multiple machines, clusters or CPU types

GLOBE Claritas : Concept

www.globeclaritas.com

Type launcher at the prompt

• Access to all Claritas tools and utilities
• Optional : all systems can be launched from the prompt
• “Mouse Over” buttons for a short description
• Tabs group applications by type/usage
• Select working directory

Getting Started : Launcher

www.globeclaritas.com

Getting Started : Where to get help

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• Trace data in a block

SEGY Seismic Traces

3200 byte reel header

• 3200 byte EBCDIC text header : user defined history

400 byte binary header

• 400 byte binary header : sample interval, trace length

240 byte header for each trace

• First 240 bytes contain header information

Seismic Trace Data : 4 Bytes per sample

• Four bytes for each digital sample : IBM 32-bit FP

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Claritas Seismic Format

• Extended SEGY format, reel header in ASCII
• Data stored as 4-byte IEEE not IBM FP
• Fixed trace-header names (CDP, SHOT etc)
• Index files created for random access and sort
• Two trace headers identified as primary/secondary keys
• Reel Header holds the processing history
• sli name provides key information on a file
• Use DISCREAD/DISCWRITE
• READSEGY/WRITESEGY for non-Claritas data

www.globeclaritas.com

Basic Components

Processing Flow

• steps to be applied in order
• processed by trace or ensemble
• parameter form for each module
• Modify – or double click - to access

Spreadsheet Files

• allow parameters vary
• can vary by header or in time
• interpolated when used

JOBS/JOB1/02_TAR.job

www.globeclaritas.com

XVIEW : interactive seismic viewer

• Interactive tools
• Basic processing
• NMO/Linear velocity
• Panel Controls
• +/- Controls
• Display mode toggle
• Panel Label

JOBS/JOB1/02_TAR.job

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Comparing Results

JOBS/JOB3/17_shot_compare.job

Selects PKEY from 100-900 Increment 100 More detail in dictionary

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Comparing Stacks

JOBS/JOB3/16_stack_compare.job

Fold mode is single MAXFOLD is 1 N_ENS is trace count

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More Complex Flows

JOBS/JOB3/13_DBS_stack.job

• Reads in a selection of 301 shots
• Creates 7 repeats
• Applies deconvolution (repeat key)
• Sorts the data to CDP order
• Removes taper on/off
• NMO and stack
• Adds an autocorrelation function
• Displays the data

www.globeclaritas.com

Common Pitfalls

• NMO, Mute, Geometry “doesn’t work”
• coord_scale incorrect : -10 for decimetres, 1 for metres
• REPEAT doesn’t work, panels don’t work
• PKEY or last trace flags wrong; DISCREAD, SETLASTR, SETKEY
• Some modules don’t seem to be applied
• Trace type is not set to 1 for live seismic; check TRTYPE
• After processing, data is duplicated
• REPEAT left active after testing, might be in DISCREAD
• After processing, data is truncated
• XVIEW used with DISCWRITE (new option in V5)
• XVIEW repeat displays not quite right
• Check traces/ensembles count / missing traces

www.globeclaritas.com

Biggest Pitfall SEGY : the non-standard standard!

• Binary header has incorrect sample rate or number of samples
• Co-ordinates and co-ordinate scalars don’t match correctly
• Extra or missing headers in file
• IBM Vs IEEE Vs 4-byte integer for samples
• ASCII or EBCDIC reel header?
• Reel header does not have “C” comment cards
• Odd headers not set (data start, data end, delay)

www.globeclaritas.com

SEGY_ANALYSER

• Check and correct headers
• Read unusual formats
• XVIEW display for QC
• trace-by-trace step through
• can build a READSEGY job
• can rewrite data (SEGY/Claritas)
• can identify IBM/IEEE issues
• can identify endian issues

www.globeclaritas.com

Wavelet : designing filters

• create filters or wavelets
• read in seismic (XVIEW)
• manipulate and compare
• match data
• phase conversion filters
• uses a macro file
• exercise in tutorial notes

www.globeclaritas.com

AREAL : interactive, spatial QC

JOBS/JOB2/GNS_job2.job

• point and click operation
• Mouse plus keyboard
• page up/down, space, R(egain)
• save flags as edits/ifinfile

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SV : Seismic Viewer

• Picking mutes, edits etc.
• First break analysis (land data)
• Interactive XVIEW (no job needed)
• Data controls : Next/previous plus sorting
• Can select toolbars for mutes, AVO etc.
• Analysis has same functions as XVIEW zoom

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CVA : Velocity Analysis Tool

• Reads stacked and unstacked file
• Must have CDP numbers in place!
• Need a guess at velocities to start

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CVA : setting up the display

• Turn on AGC
• Turn on velocity display
• Configure picking modes
• centre analysis on nearest V(t)
• set increment (eg 100 cdps)
• set T, V windows for CVG/CVS modes
• define semblance parameters
• Usually start in semblance mode
• pick at a fixed CDP increment
• easy creation of new functions
• can fine tune with CVG/CVS

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CVA : Semblance picking

Activate stack and gather panels

• Cycle button for picking mode
• Move, Add, Delete
• Can also use keyboard M, A, D
• Press and release to swap mode
• Press and hold to toggle modes
• Stack and gather both update
• Prev/Next to move
• Main display also updated

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CVA : Linked CVG/CVS fine tuning

• Panels are synchronised on the two displays
• Keep T window size reasonable
• Aim is to fine tune in shallow/deep or noisy areas
• Isovel is automatically updated
• Effectively layer-strip across dataset

www.globeclaritas.com

CVA : Isovels QC

• Circulate button controls mode
• add / delete functions
• edit or move picks
• value-replace mode
• 3D uses XVIEW-style panels
• Stand-alone version available
• Stand-along version has:
• smoothing
• interval velocity conversion
• read/write grids and traces
• gridding options

www.globeclaritas.com

JCS : Job Control System

• Some tests cannot use REPEAT easily
• Some tests take a long time to run
• Create a single master job with named variables included
• Create a spreadsheet containing the variables to be substituted
• Select one, some or all of the spreadsheet entries to run
• Create scripts, run on queues or run interactively
• Spreadsheet can be updated by the job as they run

+

www.globeclaritas.com

JCS : Migration testing

JOBS/JOB6/34_JCS_fdmig.job

• SCALAR would normally be a constant value
• Now a variable, indicated by angle brackets < >
• Create a spreadsheet of values to test

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JCS : In Operation

JOBS/JOB6/34_JCS_fdmig.job

• Scan the job for < >
• Store these in SEISJOB
• JCS file named in SEISJOB
• Tries to match names
• Asks for links where it can’t
• Select which lines to run
• Jobs named by SEQnum or

NAME