ABSTRACT: 3-D seismic imaging and interpretation of thin gas sandstone reservoirs
using multi-attribute
analysis on post-stack and AVO data, Offshore SE Sumatra Indonesia
Hidalgo, Rolando, Sigit Haryono , YPF-Maxus International Upstream, Jakarta, Indonesia
AVO and post-stack multi-attribute
analysis on 300 Km2 of 3D pre-stack time
migrated seismic data has been successfully used to define the internal character of a gas
sandstone reservoir. The reservoir in the Banuwati field comprises the Early Miocene, A
and B sandstones of the Upper Gita Member, Talang Akar Formation. Average depth is 5500
ft; channel sandstones range in thickness from 20 to 70 ft and the gas column is 200 ft. A
multistory, tectonically-controlled channel system is clearly outlined by the amplitudes
computed in a 12 to 30 ms window below the top TAF horizon. Neural network analysis
depicts the channel complex more clearly, showing significant detail such as channel and
floodplain depositional features. Stratigraphic ray tracing modeling along with AVO and
post-stack
attribute
analysis was conducted in order to delineate individual sandstones.
Interpretations of amplitude and isochron maps are consistent with results of neural
network seismic facies, matching extensive well data and conventional core description in
the Banuwati A-3 well interpreted as a tidally and marine influenced distributary channel.
Among the AVO attributes analyzed, the shear wave reflectivity subtracted from the
compressional wave reflectivity seems to be the most effective one in discriminating these
sandstones. This study has allowed making both an accurate risked reserves estimation and
a well location optimization for the Banuwati field.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia