HOW TO TIE SYNTHETIC FROM WELLS TO THE SEISMIC LINES THEY
in the introduction to the web site, sequence stratigraphy is
used to subdivide the sedimentary section into geometric packages
bounded unconformities and internal surfaces, and infer the
relationship of these geometries to changes in base level (sea
level and tectonic movement) and rates of sedimentation.
inferences and sequence stratigraphic analyses are often based
on seismic cross-sections, well logs and outcrop studies of
sedimentary rocks and are used to predict the continuity and
extent of their lithology. Usually seismic provides the regional
control on the geometries of sequences and wells are used to
determine the lithology of these geometries. To achieve this
latter a tie must be made between local wells and local seismic.
purpose of the exercise below is to introduce the common method
for tying the local stratigraphy of a region to seismic cross-sections
that dissect it.
A SYNTHETIC SEISMIC TRACE IS GENERATED
Your task is to take a well (the Zablotny #1) drilled in the
Little Knife Oil Field in the Williston Basin and tie this to
a North South seismic line across this field. To achieve the
latter a synthetic seismic trace had be generated for the Zablotny
line used in this exercise was provided by the Gulf Oil Company
and was interpreted in the two publications by Lindsay, and
Kendall l985, and Rafavich, Kendall, & Todd l984.
gain access to the un-interpreted seismic section click on the
image to left to download it or print it (click
here for a smaller version of same section). Print the file
of the seismic and the well log and follow the procedures outlined
gain access to the Synthetic trace image, click on the images
to left to download it or print it.
exercise use colored pencils to mark the location of the tops
of the Green Horn Formation, Piper Lime Formation, Spearfish
Formation, Amsden Formation, Base of Last Salt, Mission Canyon
Formation, Duperow Formation, Red River Formation, Winnepeg
Formation, Deadwood Formation and Basement on the synthetic.
Now fold the synthetic trace at the seismic trace and overlay
this on the seismic line at the location of the Zablotny #1
well. Mark the various tops on the seismic, correlate and color
these so they can be traced across the seismic line. List the
formation names of the tops where they intersect the edges of
the seismic line.
step in the exercise should be to write up a short analysis
describing the steps you have taken and the conclusions you
made based on your interpretation of the seismic line and the
gain access to the interpreted seismic section and match it
with your interpretation click on the image to left to download
it or print it (click
here for a smaller version of same section).
more information on impedance, reflection coefficients and synthetic
seismic review the Schumberger Oil Field Glossary) and Acoustic Impedance.
Kansas Geological Survey, Open File Report 96-50
provides more details on synthetics and tying of wells to seismic
University of Southern Ontario provides good introduction
to Synthetics and Seismic Interpretaion.
The Ocean Drilling Program (ODP) provides excellent
section on Seismic Stratigraphy and Synthetics.
The Geophysical Corner of AAPG EXPLORER has a good
section on various geophysical concepts. (this is an example
link to principles of VSP).
ESIinfo basic geophysical terminology.
University Fault/Horizon Interpretation Using Kingdom Suite
Tech Seismic Resources on the World Wide Web
wave theory in the US: 1991--1994: Jeffrey Park from Yale
University/Department of Geology and Geophysics provides a good
review of seismic wave theory complete with references.
(The Consortium For Research in Elastic Wave Exploration Seismology)
provides excellent bried introduction of wave conversion with
outstanding graphics for clarifying concepts.
- Relating Boreholes or Outcrops to Seismic Data: Synthetic
Seismograms and Other Tools. This is an excellent introduction
to creating synthetics with many images illustrating the various
tools and obtained images.
of Lausanne page that deals with Teaching seismic interpretation
provides introduction to reflection seismology and 3D seismic
School of Mines Reservoir Characterization Project/Chapter
on Surface Seismic Calibration deals with how synthetic seismograms
are created and how they can be utilized for seismic interpretation.
Geological Survey section on Seismic records and the synthetic
seismogram provides clear steps needed to compute synthetic
seismograms using sonic logs.
R.F., and C.G.St.C.Kendall, Depositional facies, diagenesis,
and reservoir character of Mississippian cyclic carbonates in
the Mission Canyon Formation, Little Knife Field, Williston
Basin, North Dakota: in P.O. Roehl and P.W. Choquette eds. Carbonate
petroleum reservoirs: Springer Verlag New York, p. l75-l90.
l984 Rafavich, F., C.G.St.C.Kendall,
and T.P. Todd, The relationship between acoustic properties
and the petrographic character of carbonate rocks: Geophysics,
v. 49, p. l622-l636