Seismic
Amplitude Anomalies at Mestena Grande Field
Richard Burnett
Mestena Grande field is located in northeast Jim Hogg County, Texas. Gas and
condensate are produced from the middle lobe of the middle Eocene Queen City
Formation. The Queen City is approximately 100 ft thick and the middle lobe, the
main reservoir, is only 30 ft thick, which is well below tuning thickness.
Porosities in the producing sands are generally 15-25% and permeabilities are
usually 15-25 md, the maximum about 80 md. The most recent seismic
data exhibit
amplitude anomalies that have some correspondence with the production. The
strongest amplitudes are from the vicinity of the better wells and increase with
offset. Most of the dry holes are on weak amplitudes that decrease with offset.
Modeling
the AVO response of a productive well, however, has predicted an ampl
tude decrease with offset. This disagreement is attributed to the lack of
accurate shear wave velocities and the very thinly laminated sands.
AAPG Search and Discovery Article #91029©1989 AAPG GCAGS and GC Section of SEPM Meeting, October 25-27, 1989, Corpus Christi, Texas.