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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
Phase
and Polarity Issues in Modern Seismic Interpretation
Consulting Reservoir Geophysicist, 1911 Country Brook Lane, Allen, TX 75002, phone: +1-214-544-7183,
fax: +1-214-544-0452, [email protected]
Zero phase
is the objective of almost all seismic data processing today and its interpretive benefits are well known.
However it is difficult to achieve. No more than 50% of seismic data achieves zero
phase
sufficiently closely for its benefits
and accuracy to be properly enjoyed. Furthermore 90 degree
phase
is a remarkably common accident and, if not identified,
can cause havoc to detailed seismic interpretation.
All interpreters should know how to visually assess the phase
and polarity of their data. I regularly meet those who discover
late in the interpretation that the data has a different
phase
or opposite polarity to what was first thought. In this paper
recommendations for
phase
and polarity assessment will be made, and several
phase
circles will be presented.
For zero phase
data time and amplitude are colocated, and many interpretive procedures on modern workstations are
based on this fact. For other phases complications arise, because time and amplitude are in different locations. Suggestions
will be offered for handling the all-too-common 90 degree
phase
data.