This document discusses carbonate sedimentology and how it differs from clastic sedimentology. Specifically, it notes that while interpretation techniques used for clastic reservoirs can also be applied to carbonates, carbonates are distinct due to the importance of biogenic processes and their susceptibility to diagenetic modifications. It also outlines some of the classification schemes for carbonate rocks proposed by Dunham and Folk, and lists examples of sedimentary structures that can occur in carbonates, including both biogenic and diagenetic structures.

1. Carbonate sedimentology/1
• Interpretation techniques applied to clastic
reservoirs can also be applied to carbonate
depositional systems.
• Carbonates however, differ from clastics due to
the importance of biogenic processes and their
susceptibility to diagenetic modifications.
Carbonates versus clastics

2. Carbonate sedimentology/3
Dunham (1962)
Carbonate classification

3. Carbonate sedimentology/4
Folk (1962)
Carbonate classification

4. Carbonate sedimentology/5
• All primary sedimentary structures recognised in
siliciclastic rocks can occur in carbonates
(e.g. cross-bedding in ooid shoals, slumps etc.)
• In addition there may be:
– Biogenic structures (reefs etc.)
– Diagenetic structures unique to carbonates
Sedimentary structures

5. Carbonate sedimentology/6
Carbonate lithofacies – core calibration
Vertical well
Boundary between FMI facies FMI7 and FMI4. The
burrowed surface is clearly visible (arrowed) as are the
packstone-filled burrows below.
Burrowed contact (dashed line)
between FMIF7 and FMIF4. Burrows
(squares) are filled with packstone.
Possible hardground.
FMIF7
FMIF4
Static image Dynamic image Slabbed core

6. Carbonate sedimentology/7
Carbonate lithofacies
FMI image facies associations vs Ka
0.01
0.10
1.00
10.00
100.00
1000.00
0 1 2 3 4 5 6
FMI image facies association
Ka
(mD)
FMIA1
FMIA2
FMIA3
FMIA4
FMIA5

7. Carbonate sedimentology/8
Conductive fracture
Resistive fracture
Fractures in carbonates
Vertical well

8. Carbonate sedimentology/9
The ultimate goal