A Well Driven Processing Approach for Seismic
Imaging of Subtle Traps
By
Ahmed Abdou1, Tarek Nafie2, Ayman Shabrawi2
(1) Khalda Petroleum Company, Cairo, Egypt (2) WesternGeco, N/A, Egypt
At present the choice of both processing sequence and seismic
processing
parameters relies on the skills and experience on the part of the processing
analyst. Typically, processing parameters selection is performed by inspection
and subjective judgment of
seismic
data processed through a variety of
processing steps and parameters. However, examination of this conventional
processing technique shows that it fails in many cases to provide a good tie
with borehole
seismic
data, which in turn does not allow reliable interpretation
of the
seismic
data. This paper demonstrates an alternative processing technique
for integrating borehole data into the processing parameters selection from the
earliest stage of the processing. The present processing technique is based upon
(1) proper editing of the well acoustic data (sonic and density). The log
editing is based on multi-log approach and is carried out interactively and by
direct interaction between borehole and
seismic
data, and (2) quantitative and
objective evaluation of the processing parameters selection obtained from the
integration of borehole and
seismic
data by means of statistical attributes
calculation of the extracted wavelets. These attributes values define both the
best correlation between the well trace and the corresponding
seismic
trace and
the complexity of the extracted wavelet. The present processing technique is
illustrated with data from an oil field from the Egyptian Western Desert.
Benchmark results have proven the superiority of
seismic
imaging results
obtained by the present processing technique with respect to that obtained by
the conventional processing. The present methodology offers two major advantages
over the conventional processing approach. First,
seismic
data shows a better
focusing of the fault shadows and more certainty of the fault pattern
alignments. Second, it provided an improvement in the tie between the surface
and the borehole
seismic
data so that events on the processed
seismic
data can
be easily identified in terms of polarity and time.