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Geologic Principles
Published in Stephen M. Testa, Geological Aspects of Hazardous Waste Management, 2020
Effective porosity (Ne) is defined as the percentage of the interconnected bulk volume (i.e., void space through which flow can occur) that is not solid material. () Ne=interconnected pore volumebulk volume×100
Soil Mechanics
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Soil or other material may have high porosity, but unless the pores are connected, the porosity may not lead to high rates of fluid flow (high hydraulic conductivity). Additionally, fractures may increase the void space in a given sample, providing non-pore space for water and air to occupy. So, engineers define effective porosity (generally only for rocks, not for unconsolidated material), which is the porosity that contributes to fluid flow. Effective porosity is a very important property when considering production of oil or water from wells, because it does not matter what the total porosity is if there is no flow. For example, the material depicted in Figure 15.11 has much interconnected pore space, but the fracture ends create stagnant zones with little to no fluid flow. These zones may significantly affect important properties such as reservoir production, and the effective porosity may be considerably less than the total porosity.
Rocks and civil engineering
Published in A.C. McLean, C. D. Gribble, Geology for Civil Engineers, 2017
The effective porosity is the ratio of the volume of interconnected voids to the total volume of the rock. Voids in rocks are most commonly of two types: primary voids (pores) between the fragments of clastic rocks, and secondary voids, produced by later fracturing or chemical weathering. The first is characteristic of the whole rock mass and is its ‘porosity’ by strict definition. The second depends on the rock's subsequent history and is highly variable within the body of rock. Representative values of (true) porosity are given in Table 7.3.
Role of diffusion osmosis on the mechanical and petrophysical alterations of shale when interacting with aqueous solutions
Published in Geosystem Engineering, 2022
Hawra Al-Sarraf, Talal Albazali, Ali Garrouch
Reservoir quality is characterized by two main parameters: porosity and permeability (Busch et al., 2017). Permeability is a measure of ease of fluid flow through porous media, while porosity is defined as the rock’s ability to store fluids. There are two main types of porosities: total and effective porosities. Total porosity is the ratio of the rock’s pore space volume to the rock’s total bulk volume, while effective porosity is related to the connected pore space volume. Effective porosity is considered as one of the most important petrophysical properties of sedimentary rocks since it directly affects permeability and fluid flow (Rahmouni et al., 2014). Water and solute entrance into shale may alter its initial effective porosity and hence its permeability (Kuila et al., 2014). It has been argued that changes in shale’s effective porosity could impact shale’s permeability, compressive and tensile strengths, pore pressure, membrane efficiency and water content which ultimately could lead to shale instability (Al-Bazali et al., 2007; Santos & Perez, 2001).
Pervious concrete as an alternative pavement strategy: a state-of-the-art review
Published in International Journal of Pavement Engineering, 2020
Barnali Debnath, Partha Pratim Sarkar
In general, porosity is defined as the ratio of void to the total volume of the specimen which is further divided as ‘effective porosity’ and ‘inactive porosity’. Montes et al. (2005) first pointed out that all the voids or porous spaces in concrete were not effective in holding and transporting fluid flow and termed these as inactive void (also called isolated void or impermeable void). Effective porosity indicates those voids (effective and permeable voids) that are able to transmit fluid and help in water percolation through porous medium. These observations provide a remarkable conclusion that a higher porosity level does not ensure higher permeability rate for any material, rather it depends on the distribution of pores. Wimberly et al. (2001) stated the effective porosity as the fraction of total porosity that was allowed to drain within 30 minutes and attributed this as ‘rapid flow porosity’, as the fluid would quickly flow from the porous medium.
Assessment Techniques for Studying the Effects of Fire on Stone Materials: A Literature Review
Published in International Journal of Architectural Heritage, 2020
Edite Martinho, Amélia Dionísio
Porosity is a measure of the void space in a material, which makes it one of the most important physical properties for characterizing porous stone media. Because it directly or indirectly influences so many mechanical-physical properties, porosity is also considered the most important stone parameter (Siegesmund and Durrast 2011). It plays an important role in stone decay and is also modified by decay processes. Increased porosity favours processes that lead to stone weathering (Ruedrich et al. 2011; Viles et al. 1997). Different classification systems based on geological origin or pore connectivity, for example, can be used to describe porosity and pore space in stone material. Porosity itself can be classified in terms of total (also termed absolute) or effective (also termed open or connected) pore connectivity (Chaki, Takarli, and Agbodjan 2008). Total porosity is the total void volume per unit volume of stone and includes all existing pores, whether connected or not. Effective porosity is the interconnected pore volume; it contributes to fluid flow through the material and is classically quantified by permeability measurements (Wang et al. 2004). Effective porosity is typically less than total porosity and is of primary interest in decay processes.