Integrated Reservoir Characterization from Core to
Geomodel:
Example
of a Cretaceous Mixed Clastic/Carbonate Oil
Field
, West
Africa
Duval, Christine 1; Mabille, Cedric 2;
Virgone, Aurelien 2; Rebelle, Michel 1; Vernay, Paul 1
(1) EP/GSR/TG/COP/INT, Total, Pau, France. (2) EP/GSR/TG/ISS/CARB, Total, Pau,
France.
A cretaceous mixed clastic/carbonate oil field
is described
throughout an integrated study from sedimentary context to static reservoir
model.
Core data
understanding of
field
sedimentary and diagenesis
evolution is integrated with petrophysics and log responses to provide
Petro-Geological Groups (PGG). These PGG are to be relevant both for
electro-facies modeling from logs and for geological facies maps and trends
used to populate the geomodels.
On the other hand, Petrophysical Groups (PG), strictly relying on
petrophysical properties, appear to be more pertinent for petrophysical
parameters distribution. Regarding saturation laws, several approaches were
attempted to model them from PC data
(Wooddy-Wright-Johnson; J Leverett
function, Sw as function of height above free water level), the last one being
finally selected for geomodeling purposes.
Petrophysics (porosity, permeability, saturation) will be consequently propagated into the geological model through a relationship between PGG and PG. To establish this relationship was a key issue for geomodeling.
A supervised model of PGG provides a good result in terms of petrophysical characterization and propagation for most of the studied wells. The vertical sequences and lateral evolutions on maps validate their geological consistency. The Similarity Threshold Method (STM) computed for this supervised model highlights the good reliability of the propagation with regards to the log responses. This propagation on all wells is the base for sedimentary and diagenesis maps and evolution trends.
In such a heterogeneous carbonate field
, the comparison between
small scale permeability derived from cores and logs and larger scale
permeability derived from well test demonstrates upscaling rules which are
consequently implemented to improve the reservoir models.
This integrated study provides geological and petrophysical guidelines to populate the reservoir model and improve its overall consistency.
AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.