How do you calculate effective porosity?
The volume of water required to fill the voids is the VI and effective porosity is computed as ne = VI / VT .
What are the effects of an effective porosity?
An effective porosity is defined as the ratio of volume of interconnected pore space to total volume of a porous sample. It controls the magnitude of fluid flow and is a key parameter in the assessment of recoverable resources.
What do you mean by effective porosity?
Effective porosity is that portion of the total void space of a porous material that is capable of transmitting a fluid. Total porosity is the ratio of the total void volume to the total bulk volume.
What is the difference between porosity and effective porosity?
1. n. [Geology] Effective porosity excludes isolated pores and pore volume occupied by water adsorbed on clay minerals or other grains. Total porosity is the total void space in the rock whether or not it contributes to fluid flow. Effective porosity is typically less than total porosity.
Is core porosity total or effective?
The standard reported core porosity, ϕc, is, therefore, a total porosity including the effective porosity, ϕe, and the clay-mineral adsorbed water volume, Vclϕcl or Vshϕsh. OBM-core Sw determined using Dean-Stark water-volume extraction is also accomplished with boiling toluene at approximately 110°C.
How do you measure porosity of a rock?
Imbibition method: This property is used to determine effective porosity of the rock. In this method the weight of a dry sample is measured and then the sample is immersed under vacuum in water or any other fluid that rock has the tendency to imbibe.
What is ineffective porosity?
1. n. [Geology] The interconnected pore volume or void space in a rock that contributes to fluid flow or permeability in a reservoir. Effective porosity excludes isolated pores and pore volume occupied by water adsorbed on clay minerals or other grains.
What is the difference between effective porosity and permeability?
More specifically, porosity of a rock is a measure of its ability to hold a fluid. Mathematically, it is the open space in a rock divided by the total rock volume (solid and space). Permeability is a measure of the ease of flow of a fluid through a porous solid.
What is absolute and effective porosity?
The interconnected pores that support the flow of fluids make up the effective porosity, which is numerically less than the absolute porosity, that is, the intercommunicating porosity excluding the pores containing irreducible fluid saturation.
What are the four types of porosity?
Four basic porosity types can be recognized in sandstones: (1) intergranular (primary), (2) microporosity, (3) dissolution (secondary), and (4) fracture (Figure 2). Intergranular porosity exists as space between detrital grains.
Which rock has the highest porosity?
Clay is the most porous sediment but is the least permeable. Clay usually acts as an aquitard, impeding the flow of water. Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.
What is the maximum porosity?
Porosity is the percentage of void space in a rock. It is defined as the ratio of the volume of the voids or pore space divided by the total volume. It is written as either a decimal fraction between 0 and 1 or as a percentage. For most rocks, porosity varies from less than 1% to 40%.
How do you calculate porosity and permeability?
To calculate the permeability of a porous material, use Darcy’s law equation:
- Multiply together the fluid discharge rate, dynamic viscosity, and distance traveled.
- Divide the result from Step one by the cross-sectional area of the material multiplied by the pressure difference on either side of the material.
What are the three factors that affect porosity?
The porosity of a soil depends on several factors, including (1) packing density, (2) the breadth of the particle size distribution (polydisperse vs. monodisperse), (3) the shape of particles, and (4) cementing.
Which of the following is likely to have the greatest porosity?
Which of the following is likely to have the greatest porosity? porosity than coarse-grained sediments. Silt, which is a fine-grained sediment, is likely to have the greatest porosity of the listed materials.
What is the porosity of shale?
Shales are characterized by very low porosity (typically less than 5%) and very low permeability (typically less than 1,000 nD), which make them challenging in recovering economically viable hydrocarbons.