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The AAPG/Datapages Combined Publications Database
Ohio Geological Society
Abstract
OGS-AAPG
Structural Influences on Oil and Gas Reservoirs: Third Annual Technical Symposium, October 25,
ABSTRACT: ADVANCED SEISMIC INTERPRETATION OF ROSE RUN REMNANTS IN OHIO
ABSTRACT
The variety of Rose Run trap styles has outgrown simple interpretation on a black-and-white paper seismic section. A Rose Run remnant (or what looks like a remnant?) is easily identified with moderately good quality seismic data, but the critical details of the prospect remain concealed within the seismic data. The key to greater drilling success in the Rose Run play is to first understand the geology, relate the geology to the seismic data, and then interpret that data to exploit the concealed details within by using advanced seismic interpretation techniques.
The advanced seismic interpretation process begins with
quality seismic acquisition and processing
. Acquisition and
processing
should be designed on the signal and for high
frequency content. The second step is to phase-correct the
seismic data and, if applicable, enhance frequencies (whiten
data) using
interpretive
wavelet
processing
that requires a
sonic log. A sonic log provides reflection coefficients which
are used to correct for phase (and reflection identification in
wildcat areas). Once the correct phase is established, the
amplitude spectra are analyzed for frequency range and
balance. The amplitude spectra are easily whitened if the
seismic data contain high frequencies and is not
high-frequency cut. After identification and interpretation
of key reflectors is complete, isochron graphing is compared
to known geology and can indicate thickening or thinning of
rock section at the Knox Unconformity. Next, analysis of
individual reflectors is performed to enhance details in
seismic waveform and amplitude. Waveforms exhibit different
character with different frequencies and with different
geology and can provide clues to formation thickness
and geologic sequence. Detailed wavelet character is interpreted
by understanding the relationship of the local geology
to the seismic information, regional geology and the
frequency content of the seismic data. Amplitude graphs
support lithology interpretations and can indicate changes
in reservoir porosity and fluid/gas content. Time picks from
reflection interpretations are then used to construct time-
structure maps of two or more seismic lines and show local
and/or regional geological relationships between remnants.
Time picks are also used to show 2-D seismic anomaly
shapes and are interpreted for clues to paleotopography
and remnant trends (important for guiding lease and seismic programs).
Rose Run seismic anomalies typically exhibit
a low-angle dip slope (backside) and an escarpment
face (frontside). Finally, detailed seismic modeling is the
answer for questions concerning seismic anomalies, detailed
seismic character, and amplitude tuning.
ADVANCED SEISMIC INTERPRETATION PROCEDURE (ASIP) FOR ROSE RUN REMNANTS
- Do seismic acquisition and
processing
designed for a broad range frequency content.
- Phase-correct seismic data.
- Analyze amplitude spectra and whiten seismic data.
- Identify key reflectors.
- Integrate geology from local and/or regional wells.
- Isochrons
- Waveform
- Amplitude
- Isochrons
- Time-structure mapping