Here's why:
* Permeability refers to the ability of a rock or soil to allow fluids (like water, oil, or gas) to pass through its pores and fractures.
* Porosity, on the other hand, refers to the amount of empty space within a rock.
* While a rock can have high porosity, it might not be permeable if the pores are not interconnected.
Examples of permeable rocks:
* Sandstone: Has large, interconnected pores.
* Fractured limestone: Cracks and fissures allow fluid flow.
* Gravel: Large spaces between the particles allow easy fluid movement.
Examples of impermeable rocks:
* Granite: Very dense and lacks interconnected pores.
* Shale: Fine-grained, with tiny pores that are not interconnected.
* Clay: Has very small pores and often acts as a barrier to fluid flow.
