Porespace

Porespace, also known as pore space, refers to the void fraction of a porous material—the volume not occupied by solid material that can hold or transmit fluids. It is usually expressed as porosity, the ratio of pore volume to total sample volume, and is influenced by the arrangement and size of solid grains, as well as the presence of cracks or voids.

Not all pore space is equally accessible; connected porosity includes voids that can exchange fluids with the surroundings, while isolated pockets may store fluids but not contribute to flow.

Measurement and characterization of porespace employ laboratory tests and imaging. Common methods include gravimetric or volumetric porosity measurements, gas or liquid permeability tests, and surface area analysis. Imaging techniques such as X-ray computed tomography, magnetic resonance imaging, or electron microscopy reveal pore networks and size distributions. Mercury intrusion porosimetry and gas sorption provide pore size distribution data but may alter delicate samples.

In geology and engineering, porespace governs fluid storage and movement in soils, rocks, ceramics, catalysts, and membranes. It affects groundwater table and contaminant transport, oil and gas recovery, filtration efficiency, battery materials, and environmental remediation.

Factors modifying porespace include compaction, cementation, mineral weathering, swelling clays, thermal cycling, and chemical alteration. Practical interpretation must distinguish total porosity from connected porosity and consider anisotropy and pore throat distributions.