ABSTRACT: Reservoir characterization in Kaji-Semoga Field, South Sumatra, Indonesia,
using seismic inversion
and geostatistics
Tribuanawati, Dyah , P.T. Exspan Sumatera, Jakarta, Indonesia
An integrated reservoir modeling
study of the Baturaja Limestone has been conducted
using 2-D seismic
data
from Kaji-Semoga Field, South Sumatra, Indonesia, The work was
designed to aid prediction of the lateral extent of the reservoir, to build a porosity
model for use in flow simulation and reserve assessment and to evaluate uncertainty in
reserve estimation. The method involved study of seismic attributes, followed by
geological interpretation and Seismic
Inversion
modeling
using wavelet estimation from a
number of wells near the build-up. Several geo-statistical techniques for integrating well
log porosity with quantitative average porosity derived from a constrained sparse spike
inversion
method were applied in the reservoir
modeling
.
The spatial distribution of porosity in inter-well regions has been estimated based on
variogram ranges and azimuth. Continuous petrophysical properties within each facies type
were determined by application of kriging and co-kriging mapping simulation methods
.
Co-kriging was initially tested on a numerically simulated reservoir model and compared
with kriging, then a conventional least squares product technique relying only on local
correlation between porosity and acoustic impedance was applied. As compared to kriging,
the seismically assisted geo-statistical method detects subtle lateral variations in
porosity that cannot be mapped from sparse well
data
alone.
The result of the study shows that if a reservoir is seismically resolved and properly
imaged, sparse spike inversion
can be used in conjunction with geo-statistical
methods
to
obtain a more complete reservoir description.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia