meo wa360p – merge test 0100 survey merge analysis (gross amplitude) date 12/6/2014

MEO WA360P – Merge

Test 0100 Survey Merge Analysis(Gross Amplitude)

Date 12/6/2014

Following the re-gridding of the Foxhound, Artemis3D and MEO3D surveys to a common grid (based on Artemis 3D Grid), three crosslines 3600, 4000 and 5000 were extracted from the supplied Radon Demultiple data. These were stacked, the amplitude was grossly corrected as follows: For Foxhound a factor of 0.0012 was applied to the data samples and a 2dB/sec gain was applied. For Artemis3D a scale factor of 0.43 was applied to the datasamples and a 5dB/sec gain was applied. The MEO data wasn’t changed.

Surveys and Test Crosslines

Foxhound

ArtemisMEO

Rosie

XL5000

XL4000

XL3600

Raw Stacks Crossline 3600

Foxhound Artemis Artemis MEO

Post Correction Stacks - Crossline 3600

Foxhound Artemis Artemis MEO

Raw Amplitude Decay - Crossline 3600

Foxhound Artemis MEOArtemis

Post Correction Amplitude Decay - Crossline 3600

Foxhound Artemis Artemis MEO

Raw Stacks Crossline 4000

Foxhound Artemis Artemis MEO

Post Correction Stacks - Crossline 4000

Foxhound Artemis Artemis MEO

Raw Amplitude Decay - Crossline 4000

Foxhound Artemis MEOArtemis

Post Correction Amplitude Decay - Crossline 4000

Foxhound Artemis MEOArtemis

Raw Stacks Crossline 5000

Foxhound Artemis Artemis MEO

Post Correction Stacks - Crossline 5000

Foxhound Artemis Artemis MEOFoxhound Artemis Artemis MEO

Raw Amplitude Decay - Crossline 4000

Foxhound Artemis MEOArtemis

Post Correction Amplitude Decay - Crossline 4000

Foxhound Artemis MEOArtemis

Conclusions:• The corrections applied to both Foxhound and Artemis appear to broadly bring the amplitudes into balance between the three

surveys. There is however some unknown amplitude treatment that has been applied to the Foxhound dataset. Furthermore lateral velocity variations are evident and matching at the survey boundaries cannot be achieved with a single/simple function. The gross correction that has been applied is sufficient to allow further analysis of the data

Recommendations:• It is likely that a different dataset will be supplied for the Foxhound survey, so this analysis will have to be revisited when that

dataset is available. • It has been suggested that to account for the lateral variations in amplitudes between the surveys a CDP based balance

calculated in a window surrounding the target zone be used. MEO has suggested that they supply the horizon grids to define the window.