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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
Applied Physics, Delft University of Technology, Lorentzweg 1, Delft, 2600 GA, Netherlands,
phone: +31152786105, [email protected]
The Common Focus Point (CFP) technology provides a unique solution to imaging challenges attributed to the complex
near-surface. This solution is based on a wavefield propagation approach aiming at determining one-way focusing
operators from the data itself via an iterative updating process. In other words, this is obtained without deriving a complex
near-surface velocity model. The latter can be determined subsequently by tomographic inversion of the focusing operators.
The CFP technique aims at simulating a walk-away VSP experiment where the receiver is positioned at the subsurface
gridpoint under consideration and the sources are located at the acquisition
surface. Via an updating procedure a set of
one-way focusing operators is obtained, describing the wave propagation between the surface locations and points at a
chosen target reflector below the complex near surface.
In part one of this paper, two different approaches of how to estimate the focusing operators will be described, being the
automatic modelling approach and the focusing approach. The latter assumes subsurface consistency while the automatic
approach assumes surface consistency. The automatic approach is based on parameterization of the one-way focusing
operators and can be used as a good initial estimate for the focusing approach. One important aspect of the focusing
approach is that picking of events is done after inverse wave field extrapolation which gains a great deal from the
summation processes involved, and hence, resulting in an improved the signal to noise ratio. The two approaches will be
illustrated using 2D land
seismic data.