Beach Energy Ltd Lake Tanganyika 2D Marine Seismic Survey Data Processing, 2014 Source Designature Lines BST14B24 and BST14B67 Jan. 25, 2014

➢ The Designature Operator was derived using the following method ➢ Input the Source Signature wavelet that was modeled by Fugro and supplied in SEGY format ➢ Create the Minimum Phase Equivalent of the Source Signature and taper the amplitudes to remove the gun bubble pulse which adds low frequencies to the data. ➢ Using the Weiner Matching Filter, create an operator that matches the Source Signature to the tapered Minimum Phase Equivalent. ➢ This operator is the Designature Operator ➢ Test the Designature Operator by applying it to the Source Signature wavelet and check for similarity with the Minimum Phase Equivalent wavelet. ➢ This Designature Operator advances event timing by approx. 2 msec and shapes the wavelet to remove the low frequency seismic waves created by the bubble pulse. ➢ Application of the Designature Operator is recommended.

Lake Tanganyika 2D Marine Seismic Survey Location of Test Lines

Designature Operator Derivation 1. Source Signature (modeled) 2. Min. Phase Equiv. (bubble removed)

Designature Operator Derivation 3. Designature Operator 4.Convolution Output (check against #2)

Shot Records

Shot Gather 1060, Line B24(shallow water), Squelch, FXSwell Applied Before Designature Applied First break 245 msec

First break 242 msec Shot Gather 1060, Line B24(shallow water), Squelch, FXSwell Applied After Designature Applied

Stacks

Brute Stack, Line B24 (shallow water), Squelch, FXSwell, prelim. NMO applied No Designature Applied

Brute Stack, Line B24 (shallow water), Squelch, FXSwell, prelim. NMO applied Designature Applied

Zoomed Brute Stack, Line B24 (shallow water), Squelch, FXSwell, prelim. NMO applied No Designature Applied

Zoomed Brute Stack, Line B24 (shallow water), Squelch, FXSwell, prelim. NMO applied Designature Applied

Brute Stack, Line B67 (deep water), Squelch, FXSwell, prelim. NMO applied No Designature Applied

Brute Stack, Line B67 (deep water), Squelch, FXSwell, prelim. NMO applied Designature Applied

Zoomed Brute Stack, Line B67 (deep water), Squelch, FXSwell, prelim. NMO applied No Designature Applied

Zoomed Brute Stack, Line B67 (deep water), Squelch, FXSwell, prelim. NMO applied Designature Applied