Development and Application of Sedimentary Rules in Stratigraphic Prediction of Deepwater Reservoir Presence and Architecture
Stratigraphy correlates and modulates sedimentary attributes
used to characterize subsurface reservoirs. Important attributes include lithology, process facies, sedimentation units, sedimentary bodies and
sedimentation regions. These sedimentary responses are hierarchical and scale
to parameters, like slope stability and flow confinement, describing different
frequency and magnitude processes. Attributes from many examples provide a
temporal and spatial framework used to establish differences in initial
boundary conditions for parameters associated with general deepwater system
responses. These parameters represent the surface and sediment forces governing
the energy and architecture of sedimentary systems. Surface forces preserve,
shape and confine, while sediment forces modify, modulate and transform
sedimentary response. Gradient
and turbidite event magnitude govern mass
dispersion and form the principal components used to group multiple parameters
describing surface and sediment forces in deepwater systems.
The principal components are formulated into three
sedimentary rules combining co-varying parameters and hierarchical attributes
to account for nonuniform and unsteady changes in system energy. Sedimentary
systems are not self-similar or fractal because different boundary conditions
control the formation of similar features, like ripples and dunes.
Consequently, grain size limiting ripple formation cannot predict dunes scaling
to turbulent boundary layers. Though scaling to different parameters, these
sedimentary attributes do correlate to fluid properties in multipartite
turbidity currents dependent on the down-flow gradient
, the effect of turbidite
event magnitude on the cross-flow
gradient
, and longer-term longitudinal
gradient
adjustments to deposition and deformation.
Sedimentary rules correlate scalar parameters to attributes generated from observation, comparison, and verification of consistently classified outcrop examples recording known differences in initial conditions. Rule application enables larger scale patterns to be correlated to smaller scale features, or the inverse (e.g., use channel stacking pattern to predict the presence of channel-base drapes). Rule-based sedimentological detection and stratigraphic modulation of pattern variation utilizes principle components to predict complex system responses to the multiple co-varying parameters governing reservoir presence and multiple scales of heterogeneity.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California