I5Bsegmentet

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I5B-segmentet

• Vurdering av seismisk AVO-respons i slumpområder

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Top Cook depth map. Seismic profiles indicated as
red lines
L2881
3
Line 2881, I4 segment
1999 full stack
mid
far
near
Increasing amplitudes with offset indicates
oilfilled reservoir
Top Statfjord
Top Brent
Top Cook
Base Crt.
Yellow/red represents a decrease in acoustic
impedance
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Randomline, I4 segment
1999 full stack
mid
far
near
Note the opposite avo response due to the
pressure effect (blue arrow) and oilfilled
reservoir (red arrow)
Top Statfjord
Top Brent
Top Cook
Base Crt.
Yellow/red represents a decrease in acoustic
impedance
5
Top Cook depth map. Seismic profile indicated as
red line
L2995
Top Statfjord
Top Brent
Top Cook
Base Crt.
Yellow/red represents a decrease in acoustic
impedance
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Line 2995, I5B segment (prospect)
1985
1996
1999
1996
Top Statfjord
Top Brent
Top Cook
Base Crt.
Yellow/red represents a decrease in acoustic
impedance
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Line 2995, I5B segment (prospect), offset stacks
1985, full stack
mid
far
near
Top Statfjord
Top Brent
Top Cook
Base Crt.
Yellow/red represents a decrease in acoustic
impedance
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Cook-2 and Cook-3

• How much does geological setting affect seismic
  response?
• Model the seismic response in a three-layer
  setting with varying thicknesses and fluids

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How much does geological setting affect seismic
response?

• Cook-2 and Cook-3 are very different reservoirs,
  both in a geological sense and from a production
  point of view
• Cook-2 is 50-60 meters thick, while Cook-3 is
  15-50 meters thick, both thinning towards north
• In the east the formation is eroded by the BCU.
• We know that we can observe pressure build-up in
  Cook on 4D seismic
• We want to predict how water flooding will appear
  in the 4D seismic, but our model has probably
  been to coarse, mixing Cook-2 and Cook-3
  properties

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How much does geological setting affect seismic
response?

• Interfaces
• Uneroded Drake-gtCook-3
• Uneroded Shetland-gtCook-3
• Eroded Shetland-gtCook-3
• Eroded Shetland-gtCook-2
• Fluids
• Brine, oil, gas
• Thickness variations
• Cook-2 0-60 meters
• Cook-3 0-50 meters

Task Determine the seismic response in a 3-layer
model with varying thicknesses and fluids Get
parameters from geomodel!