10,372
edits
Changes
Jump to navigation
Jump to search
Line 111:
Line 111: − +
→Geological reef reservoir model
===Geological reef reservoir model===
===Geological reef reservoir model===
The geological reef model is a composite of the upward-shoaling subtidal-supratidal and karst-collapse reservoir models. The difference is that the facies tracts are compressed onto a carbonate shelf of limited aerial extent with high relief above the seafloor and with steeply sloping sides. The interior shelf or lagoon facies (Figure 2) located landward of the shelf edge normally contains a high percentage of mud. Grainstones, packstones, and boundstones associated with the reef facies are typically found along the shelf edge.
The geological reef model is a composite of the upward-shoaling subtidal-supratidal and karst-collapse reservoir models. The difference is that the facies tracts are compressed onto a carbonate shelf of limited aerial extent with high relief above the seafloor and with steeply sloping sides. The interior shelf or lagoon facies ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig2.png|Figure 2]]) located landward of the shelf edge normally contains a high percentage of mud. Grainstones, packstones, and boundstones associated with the reef facies are typically found along the shelf edge.
Compaction and cementation typically destroy the permeability of the lagoonal muds, leaving the grain-dominated sediments and boundstones of the reef edge as reservoir rocks. However, selective leaching, dolomitization, and karsting can significantly alter the permeability patterns, as discussed in previous sections. The reservoir flow units can be very complex due to the numerous possible combinations of depositional and diagenetic events.
Compaction and cementation typically destroy the permeability of the lagoonal muds, leaving the grain-dominated sediments and boundstones of the reef edge as reservoir rocks. However, selective leaching, dolomitization, and karsting can significantly alter the permeability patterns, as discussed in previous sections. The reservoir flow units can be very complex due to the numerous possible combinations of depositional and diagenetic events.