BroadSeis
Subsalt Illumination
Truly broadband data bring high resolution and layer differentiation. The reduced sidelobes create sharper wavelets for greater clarity. The six octaves of data recorded in the Gulf of Mexico provide detailed images of the near surface.
In order to achieve sufficient bandwidth in areas where high frequencies are limited, it is necessary to extend the low frequencies. Lower frequencies are affected less by attenuation, and provide greater accuracy and stability for seismic inversion.
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This 2D example from the Gulf of Mexico shows significant improvements in deep imaging, |
Conventional marine streamer acquisition lacks sufficient signal-to-noise ratio in the 2-7 Hz bandwidth due to streamer depth, streamer tow noise, source array configuration, source depth and source bubble. Using BroadSeis we routinely record frequencies down to 2.5Hz, providing three octaves of data below 20Hz.
Gulf of Mexico Examples
20Hz Salt Flood RTM showing improved illumination of the subsalt
Offshore West Africa - Gabon
BroadSeis improves penetration. In this example from the complex salt and carbonate province offshore Gabon, there is more strength in the base carbonate and salt events. The addtional character of BroadSeis data is again apparent, making layer differentiation and discrimination of different packages easier.
The main target here is below the salt and carbonate province, where the improved penetration from the low frequency content and better signal-to-noise ratio provides improved images. Pre-stack depth migration of 3D BroadSeis data would provide a further uplift beyond this be pre-stack time migration of a 2D test line.
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 Slide to compare |
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In this example from Gabon, there is more strength in the base carbonate and salt events. |
