A N D R E A C R O O K 1 , B A L A Z S N E M E T H 2 , C H R I S T I A N E S C A L A N T E 2 , Y E Z H E N G 3 , L A U R I E R O S S 3 , K E I T H M I L L I S 1
1 O P T I S E I S S O L U T I O N S L T D . 2 B H P B I L L I T O N 3 G E O - X E X P L O R A T I O N S E R V I C E S I N C .
3D SEISMIC ACQUISITION
SURVEY DESIGN FOR INTERPOLATION
OUTLINE
• Project Objectives • Designing for Interpolation • Limitations • Multi-Year Acquisition • Conclusions
OBJECTIVE Regional Focused Infill High Resolution ? +
=
METHODOLOGY Input Decimated
Geometries Combined Infill
PROCESSING • Decimated Raw Shots • Original Input Statics &
Velocities • Multi-dimension interpolation
• Anti-Leakage Fourier Transform (ALFT)
• inline, xline, offset, azimuth and time
• Post Stack Migration
DECIMATED GEOMETRIES
½ Station
DECIMATED GEOMETRIES
½ Station
Random ½ Station
DECIMATED GEOMETRIES
½ Station Random ½ Station ½ Line
DECIMATED GEOMETRIES
½ Station ½ Line
½ Sources Removed Same Average Fold & Trace Density
½ Sources & Receivers Removed Same Average Fold & Trace Density
Random ½ Station
DECIMATED GEOMETRIES
½ Station ½ Line Increasing
Fold & Trace
Density
½ Sources Removed Same Average Fold & Trace Density
½ Sources & Receivers Removed Same Average Fold & Trace Density
Random ½ Station
GEOMETRY COMPARISON
Trac
e D
ensi
ty
Offset
Fold
Based on Constant Bin Size
OFFSET LIMITED FOLD
Low Fold
High Fold
OFFSET LIMITED FOLD
Low Fold
High Fold ½ Sources Removed
½ Sources & Receivers Removed
INTERPOLATION RESULTS
½ Station Random ½ Station ½ Line
INTERPOLATION COMPARISONS
• Near Offsets
• Trace Density
• Operational Efficiencies
• Randomization
NEAR OFFSET EFFECT ½ Source & Rec Stations ½ Source & Rec Lines
NEAR OFFSET DISTRIBUTION
Small Offset
Large Offset
½ Source & Rec Stations ½ Source & Rec Lines
NEAR OFFSET EFFECT ½ Stations ½ Lines
NEAR OFFSET EFFECT ½ Stations ½ Lines
TRACE DENSITY EFFECT ½ Source & Rec Stations ½ Source Station
TRACE DENSITY
Low
High ½ Source & Rec Stations ½ Source Station
TRACE DENSITY EFFECT ½ Source & Rec Stations ½ Source Station
TRACE DENSITY EFFECT ½ Source & Rec Stations ½ Source Station
OPERATIONAL EFFICIENCY EFFECT ½ Source Line ½ Source Station
OPERATIONAL EFFICIENCY
Source Density
Source Density =
Source Linear Km
Source Linear Km >
OPERATIONAL EFFICIENCY EFFECT ½ Source Line ½ Source Station
Regular ½ Source Station Random ½ Source Station
RANDOMIZATION EFFECT
RANDOMIZATION Regular ½ Source Station Random ½ Source Station
Regular ½ Source Station Random ½ Source Station
RANDOMIZATION EFFECT
INTERPOLATION RESULTS
½ Station Random ½ Station ½ Line
LIMITATIONS
32
Original Survey Decimation with
Original Velocities & Refraction Statics
Decimation with New Velocities & Refraction Statics
REPROCESSING WITH/WITHOUT RE-PICKING VELOCITIES & STATICS
Inline
Crossline
MULTI-YEAR ACQUISITION
+ ≠
+ ≠
INCORRECT MULTI- YEAR SURVEYS
OFFSET & AZIMUTH DISTRIBUTIONS
Offset Azimuth
+
+
+ =
+ =
Correct Multi-Year Surveys
OFFSET & AZIMUTH DISTRIBUTIONS
Offset Azimuth
+
+
+ =
+ =
Multi-Year Survey Fold
Bin Size = Double Original Bin Size = Original Bin Size = Original
MULTI-YEAR RESULTS
+ +
MULTI-YEAR RESULTS
Inline Difference
+
+
MULTI-YEAR RESULTS
+
+
Crossline Difference
MULTI-YEAR ACQUISITION
+
CONCLUSIONS • Best Interpolation results achieved when:
• High-density sampling maintained in one direction • Guided Randomization applied • Well sampled near offsets
• Multi-Year acquisition possible when:
• Infill survey has complimentary attributes • high-density sampling maintained in one direction
• Design account for all processes, not just 5D interpolation
ACKNOWLEDGEMENTS
BHP Billiton
Geo-X Exploration Services Inc.
OptiSeis Solutions Ltd.