Beach Energy LtdLake Tanganyika 2D Transition Zone Seismic SurveyData Processing, 2015

De-multiple Tests

Stack Displays

Line BST14A-05 Mar. 30, 2015

The following De-multiple methods were tested:

Prestack Wave Equation Multiple Attenuation

Shallow Water Multiple Elimination Radon De-multiple

Post-Stack Post-stack De-multiple Deconvolution After Stack (DAS)

Pre-stack time migrated stack displays were created with and without post-stack processing. The post-stack processing included the following: FX Deconvoltuion Spectral Equalisation

Bandpass filterAGC

Stack Displays

Sequence

Input field data/ReformatAdd Geometry: (from SPS files)Spherical Divergence Correction: (V**2)(T**1.2)Ensemble Balance: entire record scaledLow-cut filter: 4 HzSquelch and Spurious Noise AttenuationDeghost Summation of OBX hydrophone/geophoneQuash Linear Noise AttenuationAirgun, Dynamite, Vibroseis sources matched to Marine Airgun data

Pre-stack De-multiple Tests

SC Deconvolution3 passes velocity picking, 2 passes residual staticsNMO correction: 3rd picked velocitiesPrestack Time MigrationTrace Balance: 9 windowsStack

Post-stack De-multiple Tests

Static Shift to lake levelFX DeconvolutionSpectral EqualisationAGCBandpass Filter 5-15-60-90 HzPolarity Reversal

Display: -ve = blue, +ve = redNote: positive reflection co-eff. = +ve number or red color

No De-multiple Applied, PSTM Stack, with post-stack proc.

Wave Equation De-multiple Applied, PSTM Stack, with post-stack proc.

Shallow Water Multiple Elimination Applied, PSTM Stack, with post-stack proc.

Radon De-multiple Applied, PSTM Stack, with post-stack proc.

Post-stack De-multiple Applied, PSTM Stack, with post-stack proc.

DAS De-multiple Applied, PSTM Stack,with post-stack proc.

No De-multiple Applied, PSTM Stack, no post-stack proc.

Wave Equation De-multiple Applied, PSTM Stack, no post-stack proc.

Shallow Water Multiple Elimination Applied, PSTM Stack, no post-stack proc.

Radon De-multiple Applied, PSTM Stack, no post-stack proc.

Post-stack De-multiple Applied, PSTM Stack, no post-stack proc.

DAS De-multiple Applied, PSTM Stack, no post-stack proc.