Print this page ABSTRACT: Integrating Sequence Stratigraphic Analysis and 
Reservoir
Petrophysics : a
value-added approach to Reservoir Characterization in Central Sumatra
Logan, James P. and Victor H. Noguera , Caltex Pacific Indonesia, Rumbai, Indonesia
The value of a sequence stratigraphic framework and its applications to characterizing
HC reservoirs in a given field must be measured by two critical yardsticks: 1) how
well the framework depicts the actual architecture of both reservoir and non-reservoir
rocks and 2) how well it contributes to predicting the present distribution of gas, oil
and water in the subsurface. We propose that reservoir characterization practices can be
greatly improved by the methodical integration of sequence stratigraphic analysis and
petrophysical evaluation.
Sedimentary facies models resulting from core studies during sequence analysis can help
control reservoir petrophysical models. Fundamental reservoir properties such as:
porosity, permeability, bound fluid volumes, residual oil saturation, and fluid contacts
are all quite frequently dictated by grain size variability and hence by sedimentary
facies. In sandstone reservoir systems initial formation water salinity may change based
on the architecture and connectivity of the permeable sands and the distribution of
intervening maximum flooding surface shales. These flooding surfaces can assist the
formation evaluation geologist in defining zoned petrophysical and fluid properties at the
sequence, parasequence set and parasequence (sand pay) levels. Conversely, recognition of
fluid contacts from petrophysical evaluations can assist the stratigrapher in identifying
sequence boundaries, flooding surfaces, hardgrounds, erosional lags and other important
surfaces.
This paper discusses examples from the Central Sumatra Basin which illustrate these
relationships. It also proposes a work flow that optimizes the value of reservoir
characterization studies by building on the iteration between the sequence stratigraphic
and the petrophysical work.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia