Is porosity affected by packing?
Particles’ shapes and sizes affect how they aggregate, including how tightly they can pack together, which affects a rock’s porosity—a property that is the ratio of the volume of a rock’s empty spaces to its total volume.
What is intragranular porosity?
(viii) Intragranular porosity The porosity due to voids within the rock grains. (ix) Dissolution porosity The porosity resulting from dissolution of rock grains. (x) Fracture porosity The porosity resulting from fractures in the rock at all scales.
What is the porosity of sandstone?
10 to 40%
Almost all hydrocarbon reservoirs are composed of sedimentary rocks in which porosity values generally vary from 10 to 40% in sandstones and from 5 to 25% in carbonates.
How is porosity calculated?
Porosity = ( ( Total Volume – Volume of the Solid ) / Total Volume ) x 100%. A larger percentage means that the rock has the ability to hold more water.
Which soil has maximum void ratio?
Typical values of soil void ratio for different soils
| Description | USCS | Void ratio [-] |
|---|---|---|
| max | ||
| Well graded gravel, sandy gravel, with little or no fines | GW | 0.46 |
| Poorly graded gravel, sandy gravel, with little or no fines | GP | 0.46 |
| Silty gravels, silty sandy gravels | GM | 0.28 |
Which is the most common type of porosity in sandstone?
A classification of porosity in sandstones is proposed to recognize primary and secondary porosity. Secondary porosity caused by dissolution of framework grains is very common in sandstones.
What is void ratio of soil?
Void ratio of a soil sample is defined as the ratio of the space occupied by the voids i.e. volume of voids to the space occupied by solids i.e. volume of solids. We can also write volume of solids as total soil volume minus volume of voids. Void ratio is NOT expressed in percentage like water content.
How is the porosity of Sand determined from physics?
From physics and soil mechanics, we know that the field porosity of sand is comprised between some minimum and maximum values. In the case of equal spheres, crystallography teaches that the simple cubic packing porosity is 25.95% whereas the hexagonal packing porosity is 47.64% (Smith et al., 1929).
How are pore size and porosity of soil related?
A soil’s porosity and pore size distribution characterize its pore space, that portion of the soil’s volume that is not occupied by or iso-lated by solid material. The basic character of the pore space affects and is affected by criti-cal aspects of almost everything that occurs in the soil: the movement of water, air, and other
How does porosity of unconsolidated materials depend on?
The porosity of unconsolidated materials depends on: Grain shape Grain packing Grain sorting Grain size distribution Compaction The porosity of consolidated materials depends mainly on the degree of cementation and consolidation but also on the above mentioned parameters. Grain shape and packing
How is the porosity of rocks related to fluid migration?
A pore-structure concept for rocks (Figure 2‑5) was presented (Katsube and Collett, 1973) in the 1970s, which consisted of total connecting porosity (φC) for connecting pores that contribute mainly to fluid migration and of storage porosity (φS) for storage pores that contribute mainly to fluid storage, where their sum is effective porosity (φe):