Metamorphic Processes
Sedimentary Structures
Outline
The ability of rocks to store (porosity) and transmit (permeability) fluids is one of the most important properties of sediments in economic and engineering terms. Sediments at the time of deposition are extremely porous with very high volumes of voids (space) per unit volume of sediment.
Cementation tends to reduce pore volume (porosity) and pore interconnection (permeability). Calcite, silica aand iron oxides are the common cements in sediments.
If pore space is infilled by finer sediments, both porosity and permeability are reduced massively. Clean sands free from fines (silt and clay) make the best aquifers and reservoir rocks. Dirty sands have the porosity plugged by fine particles.
Metamorphic Processes
Sedimentary Structures
Outline