LEVEY, RAYMOND A., LIANGQING XUE, and ASAD SATTAR, Bureau of Economic Geology, The University of Texas at Austin, Austin, TX
ABSTRACT: Forward Modeling
of Reservoir Architecture and
Seismic
Response in Third- and Fourth-Order Depositional Sequences: Examples from the Paleogene in the Gulf Coast Basin
Regional-scale forward structural and stratigraphic modeling
is used to evaluate variations in basin architecture and predict the
seismic
response of third- and fourth-order depositional sequences in the offlapping Paleogene sediment wedge in the onshore Gulf Coast Basin. Objectives of these
modeling
studies include the visualization of regional stratigraphic patterns based on well log cross sections and the prediction of corresponding two-dimensional synthetic
seismic
reflection response. Cross sections of resistivity and velocity parameters with variable attributes for vertical and lateral reservoir continuity are modeled with onlap, offlap, and concordant relationships forced to donor major third-order sequence boundaries. Identical cross sections are forward modeled to illustrate
he
seismic
response and are then compared to existing subregional
seismic
reflection lines.
The positions of major Frio plays, fields, and reservoirs are projected
into cross sections from the Rio Grande Embayment, the San Marcos Arch, and the Houston Embayment. Structural and stratigraphic cross sections show the variability in both well log and seismic
response across the Vicksburg fault zone and into the downdip expanded Frio section. A depositional dip-orientedexample from Oligocene third-order depositional sequences in the Rio Grande Embayment shows an onlapping fourth-order reservoir stacking pattern in the basin fill that coincides with fluvial reservoirs that have undergone infield gas reserve growth.
Modeling
results suggest that repetitive patterns attributed to depositional and structural controls on fourth-order reservoir stacking can be recognized and potentially extrapolated to understand the distribution of reservoirs in other seq
ences in the Gulf Coast Basin or other passive margin settings.
AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.