What Does Interconnected Porosity Mean?
Interconnected porosity is a network of pores on a coating surface.
There are two kinds of porosity - open and closed:
- Open porosity, also known as interconnected porosity, is the ratio of the volume of void space within the material that is accessible from the exterior to the bulk volume.
- Closed porosity, also known as internal porosity, is the ratio of the volume of void space within the material that is not accessible from the exterior to the bulk volume.
The total porosity of a material is the sum of the open and closed porosity.
Corrosionpedia Explains Interconnected Porosity
Porosity can be classified based on either its geological origin or pore connectivity. In terms of pore connectivity, porosity can be either total or effective
- Total porosity includes all existing pores regardless of whether they are connected or not.
- Effective porosity only includes interconnected pores. The effective porosity is of great importance in considering the suitability of rocks or sediments as oil or gas reservoirs, or as aquifers.
The interconnected porosity is a part of the total porosity of sintered products. As in the case of total porosity, the degree of interconnected porosity, distribution of pores in the material and their size depend on numerous factors, of which the main ones are:
- Compaction pressure
- Temperature and time of sintering
- Quality of metal powder and manner of its manufacture
- Particle size and distribution
- Factors affecting pressure distribution in the compact
The most important factor controlling the porosity degree, including the interconnected porosity, is the compacting pressure.
It should be noted that the porosity does not give any information concerning:
- Pore sizes
- Pore distribution
- Degree of pore connectivity
Thus, rocks of the same porosity can have widely different physical properties. An example of this might be a carbonate rock and sandstone. Each could have a porosity of 0.2, but carbonate pores are often largely unconnected, resulting in its permeability being much lower than that of the sandstone.
The initial porosity is affected by micro-structural parameters:
- Grain size
- Grain packing
- Particle shape
- Distribution of grain sizes
However, the initial porosity is rarely that found in real rocks, as these have subsequently been affected by secondary controls on porosity such as compaction and dilation processes.
Porosity is of primary importance in reservoir engineering because it is a measure of the space available for storage of commercial fluids within a reservoir rock. If the dimensions of the reservoir are known (area and thickness), the total volume of fluids stored in the reservoir can be calculated.
Reservoir rock has interconnected pores filled with fluid (oil, gas, water) that can flow through the rock. A range of differently defined porosities are recognized and used within the hydrocarbon industry.