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Curvature and coherence attributes – a definite
aid in seismic interpretation
Presented by Satinder
Chopra
March 20th or
29th, 2007
11:45 to 1 pm (lunch provided)
Suite 2600, 111 - 5th Ave SW, East Petro-Canada Tower
Limited seating, click here to
RSVP
This
is the second in a series of lunch & learn seminars, see
the sidebar for information on the other topics.
Seismic attributes have proliferated
in the last three decades at a rapid rate and have helped in making
accurate predictions in hydrocarbon exploration and development.
They are widely used for lithological and petrophysical prediction
of reservoir properties. Attribute computation on seismic data is an art.
There are many ways to bring out the features of interest in 3D seismic
data volumes, some subtle and some prominent. Apart from the choice of
the computation parameters, the input data needs to be conditioned, and
the choice of algorithms make a significant difference to the quality of
the results. Some of these ways will be discussed in the presentation.
During the last few years, curvature attributes
have been found to be useful,
for delineating faults and predicting fracture orientation and distribution.
There are different curvature measures that can be used, each having its own
characteristic property. Curvature computation is not only restricted to
horizon-based surfaces, but has been extended to volume computation as well.
The orientations of faults and fracture lineations interpreted on curvature
displays can be combined in the form of rose diagrams, which in turn can be
compared with similar diagrams obtained by FMI well logs to gain confidence
in calibration.
Coherence measurements in three dimensions represent
the trace-to-trace similarity
and therefore produce interpretable changes. Similar traces are mapped with high
coherence coefficients and discontinuities have low coefficients. Regions of
seismic traces cut by faults for example, result in sharp discontinuities in
trace-to-trace coherence, producing delineation of low coherence along fault planes.
Since three-dimensionality is an essential ingredient of coherence computation,
faults or fractures in any orientation are revealed equally well. Stratigraphic
features generate similar discontinuities resulting in sharp detection of reef and
channel boundaries and deltaic sediments. An attractive characteristic of coherence
cubes is that it gives an unbiased view of the features in the seismic volume –
no interpretation is required for viewing them.
Examples will be presented for the application of curvature
and coherence attributes to 3D seismic volumes to show how these attributes can aid the
geophysicist in making more accurate interpretations.
To learn more, attend the
lunch & learn session on March 20 or March 29.
Click here to RSVP.
This course is
available as a free in-house seminar. For more
information contact Florence Janzen, 781-1437 or email
fjanzen@arcis.com. |
