Print this pageSeismic Expression of Marts Field (Silurian Reef) in Sullivan County, Indiana
H. J. Renick, Jr., R. M. Rene, N. C. Hester, F. L. Stanonis
The Marts field of Sullivan County, Indiana, is associated with a Silurian
reef that is part of the Terre Haute bank on the eastern flank of the Illinois
basin. Gas production has come from Pennsylvanian sandstones at Marts field, and
oil is presently being produced from limestones of the Devonian Muscatatuck
Group. Hydrocarbons were trapped in the Devonian limestones because of
structural
drape over the reef. A 2.8-km (1.8-mi) north-south 24-CDP reflection
seismic profile across the Marts field was obtained by using a
hydraulic-assisted weight drop with a source array interval of 16.7 m (55 ft).
The data were digitally processed through statics corrections, deconvolution,
stack, and migration. These data clearly image drape in Carboniferous and
Devonian strata, a characteristic chang in reflection pattern at the reef
flanks, and diffractions associated with the reef flanks. Near Marts field, one
well penetrates Silurian strata, and a synthetic seismogram for this off-reef
well is tied to the seismic section.
Using well data from Marts and other reefs, mirror-imaged cross-plots of
depths to tops of formations vs. depth to top of the Devonian limestone aid in
examination of the drape. These plots of "transformed cross sections"
approximate those of vertically stacked right circular cones indicative of the
linear relationships between depths to formations.
AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.
