Importance of
Facies-Based Earth Models for Understanding Flow Behavior in Carbonate
Reservoirs
Levy, Marjorie1, William
Milliken1, Paul Harris1, Sebastien Strebelle1,
Eugene Rankey2 (1) Chevron Energy Technology Company,
Reservoir models attempt to mimic the
distribution of reservoir properties in subsurface systems, and in carbonate
reservoirs should capture geologically meaningful and realistic heterogeneity.
Comparing SGS-generated models with facies-based Multiple-Point Statistics
(MPS)/Facies Distribution Models (FDM) highlights the importance of
incorporating facies into models. These facies-based models provide a template
to test which carbonate characteristics have the greatest impact on subsurface
flow.
To explore different types of carbonate
platforms, reef- and grainstone-dominated systems were simulated using training
images, FDM cubes and MPS simulations. On the basis of modern analogs from the
Two types of flow experiments are run:
(1) the impact of depositional facies is tested keeping all other parameters
the same; and (2) an experimental design guided set of experiments varying a)
proportions of reservoir facies vs non-reservoir facies, b) proportions of bar
flank/bar crest reservoir facies, c) dimensions of facies, d) diagenetic zones,
e) stratigraphic cyclicity, f) spatial distribution of reservoir facies
(distributed across platform vs. localized), g) shape of reservoir facies (bars
vs. crescents), h) porosity histogram, and i) permeability transform. Each
model was tested using reservoir simulation and considered different
development scenarios and recovery processes. Models were compared on the basis
of static measures of OOIP, reservoir connectivity, and permeability
heterogeneity; and on the basis of dynamic measures of recovery factor vs.
time, recovery factor vs. pore volumes injected, net present oil, cumulative
oil produced, and water breakthrough time.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California