The E&P Synthesis
on Clastic Reservoirs addresses practical
distinction of different clastic play
types and understanding of the various
controls on reservoir performance and
recovery efficiency using 200 clastic
field analogs worldwide. We classified
various clastic reservoir plays with
emphasis on reservoir distribution and
architecture. Six major play types have
been defined: 1) fluvial plays, 2) desert
plays, 3) lacustrine plays, 4) coastal
plays, 5) deep-marine plays, and 6)
glaciogenic plays. For each play type,
important exploration lessons are summarized
by: 1) examining the pre-discovery concepts,
including evolution of concepts and
discovery methods and 2) analysing the
test results of exploration wells and
their implications. These are followed
by detailed discussions on the various
play elements (i.e., reservoir distribution
and external geometry, depositional
facies and reservoir architecture, reservoir
quality, source rock characteristics,
trapping configuration) and their coordination
in petroleum systems to provide better
exploration approaches and strategies
for the various play types.
For the purpose of field development,
the studied reservoirs have been grouped
by examining their production history.
The geological, fluid and engineering
features within each of the groups are
analyzed to find out the most important
factors in producing the observed production
consequences. This approach has produced
five groups of clastic reservoirs: 1)
heavy oil/tar reservoirs, 2) low-permeability
conventional-oil reservoirs, 3) intermediate-permeability
conventional-oil reservoirs, 4) high-permeability
conventional-oil reservoirs, and 5)
gas and gas condensate reservoirs. For
each reservoir type, multi-variable
statistical analyses have been carried
out in order to understand the relationship
between recovery efficiency on the one
hand, and API gravity, viscosity, well
spacing, reservoir depth, field size,
depositional facies, reservoir architecture,
net/gross ratio, drive mechanism and
poro-perm characteristics. Systematic
analysis and comparison of depletion
curves for the different reservoir types
and/or under different producing mechanisms
have allowed a better understanding
of the various controls on reservoir
performance and recovery efficiency. [view
outline]
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