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See also
rock physics
computer mapping
depth conversion
well to seismic ties

Two examples of how some interpretation technologies, especially AVO, have been used.

Being brought up to date
Example 1. Mapping the Areal Extent of the Oil-Water Contact of a North Sea Oil Field
The acoustic impedance between the Forties Sandstone and the overlying Sele Shale is reduced when the Forties sst reservoir is filled with hydrocarbons.

Seismic Profile
Reduction of the Top Forties [arrowed]
acoustic impedance due to hydrocarbon fill.
A simple amplitude extraction of the picked Top Forties seismic horizon, [Map A], readily shows the outline of the oil-water contact as the contrast between strong and weak amplitudes.
The white contour shows the position of the oil-water contact derived from well logs, after depth conversion of the Top Forties time pick.

This image of the contact has been "sharpened" up, [Map B] by normalizing the extracted amplitudes against those from a geologically consistent unit which is also reasonably close,  in vertical seperation terms.

Map A
Amplitude extraction of Top Forties seismic pick.

Map B
Sharpened image after amplitude normalization.


Example 2. Intra Chalk Amplitude Anomaly of the North Sea's Central Graben

Gas in the Hod unit of the Cretaceous Chalk can be an exciting commercial possibility.  Equally, it can be a dangerous and costly hazard for wells testing the deeper, pre Cretaceous, high temperature and high pressure reservoirs, if it is not detected before drill planning.
These anomalies can be very quickly mapped using standard volume tracking programs or the latest voxel based trackers.

Here, such an anomaly has been analysed in terms of its AVO response.

Offset Stacks
Amplitude comparisons of near, mid and far traces.

Comparisons of the amplitudes at increasing seismic offsets show that the amplitude in fact decreases with offset suggesting that this anomaly may be associated with lithological change rather than with fluid fill.  Further AVO modelling studies based on the nearest offset wells is necessary to evaluate the anomaly further.