Print this pageModeling Diagenesis of Icehouse Platforms Using CARB3D+
Paterson, Richard1,
Peter Smart1, Fiona Whitaker1, Gareth Jones2,
Graham Felce1 (1)
A fundamental challenge in carbonate reservoir characterization
is predicting the spatial distribution of early diagenesis, which in turn can
have a critical control on porosity and permeability heterogeneity. During
icehouse times, high-amplitude sea level oscillations cause repeated vertical
migration of the water table and underlying hydrological zones, and large
variations in vadose zone thickness. The consequent diagenetic overprinting
generates a complex pattern of cementation and secondary porosity and
permeability in the reservoir, which is difficult to predict from seismic data
or interpolation between cored wells.
CARB3D+ is an innovative 3D forward modelling program that can
predict the co-evolu-tion of sedimentary facies and early diagenesis in a
sequence stratigraphic context. This can improve the accuracy of predictions
and yield multiple scenarios of reservoir quality for input to geological
models.
Preliminary results from CARB3D+ show complex icehouse
overprinting generates spatial and temporal patterns in hydrological zone
residence times that can be linked explicitly into the sequence stratigraphic
framework. Model output can be tied directly to well-core via exposure
surfaces. Results also show the importance of ‘missed beats’ in the creation of
major exposure horizons, with different hydrological zone residence time
patterns occurring for progressive higher order sea level fluctuations. Because
relative sea level is an important control on both sequence stratigraphy and
diagenesis, the simulated sequence stratigraphic framework provides a useful
constraint on prediction of early diagenetic evolution.
Through a
process-based modelling approach, it is now possible to predict complex diagenetic
overprint patterns through carbonate platforms, during icehouse times.