Reservoir Characterization of the Fluvial T.A.G.I. Sandstones, Central Ghadames Basin, Algeria
DRUMHELLER, RICHARD E., ROBERT P. DANIELS, and JEFFREY M. YARUS
The reservoir characterization of the Triassic Argileux Greseux Inferieur
(T.A.G.I.) fluvial sandstones in the central Sahara region of Algeria presents
the challenge commonly faced early in the development sequence of petroleum
reservoirs: a significant lack of specific local reservoir data.
The essential description of the reservoir necessary for proper production
planning includes log and core data from the first few wells, indistinct local
seismic
information, production test data, which are complemented by extensive
regional studies of the T.A.G.I., and by analogy with apparently similar fields
elsewhere. The data was incorporated into 3-D stochastic models as it became
available, and numerous geostatistical realizations were constructed for use in
mapping and reservoir simulation studies. The stochastic model has been able to
reasonably well represent the sedimentologic environments and to capture a
measure of the reservoir heterogeneities present in the T.A.G.I.
The output from the stochastic modeling
has proven very useful for all types
of reservoir simulation, both 2-D and 3-D. The
modeling
products provided an
important influence on initial sets of conventional deterministic geologic maps
constructed for the benefit of production planning, and for an enhanced
geological understanding to be applied to local field development and to further
exploration in the region.