Effectiveness
of Grain Coatings on Preserving Reservoir Quality in High-Temperature, Deep
Burial Settings
Tobin, Rick1 (1) BP America,
Inc,
Grain-coating clays and early diagenetic
cements help to preserve reservoir quality in sandstones by forming barriers to
quartz cement nucleation. Reservoir quality modeling software are useful for
quantitatively predicting the effect of grain coating completeness on porosity
preservation in high-temperature, deep burial settings. The effect of grain coating
completeness was evaluated for various formations in the deep gas trend in the
Model simulations and natural
observations further indicate that the minimum degree of grain coating
completeness required to retard quartz cementation also depends on grain size
and framework composition. For sandstones buried to equivalent temperatures,
the degree of grain coating completeness required to retard cementation is
greater for sandstones that are rich in detrital quartz than for lithic or
feldspathic varieties. Similarly, fine-grained sands require more complete
grain coatings to retard quartz cement than coarse-grained sands.
Reservoir quality risk analysis in
high-temperature, deep-burial settings must take into account the degree of
grain coating completeness along with textural and compositional variability.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California