Porosity is the quality of being porous, or full of tiny holes. Liquids go right through things that have porosity. It is shown as a fraction of the volume of voids over the total volume, which is between 0 and 1, or between 0% and 100% as a percentage. Primary and secondary porosity can be read directly from neutron, density, and sonic logs.
1. Soran University
Faculty of Engineering
Department of Petroleum Engineering
Petroleum Geology
Title: Porosity Measurement
Lab Number: 2
Name: Raboon Redar Muhammed
Lab Date: 13/10/2019
Supervisor(s): Mr. Foad Yousefi
Ms. Meriam
2. 1 | P o r o s i t y M e a s u r e m e n t
1. Aim
The main aim of this experiment is to find out the porosity of a rock.
2. Introduction
Porosity is the quality of being porous, or full of tiny holes. Liquids go right through things that have
porosity. (Vocabulary.com, 2019) It is shown as a fraction of the volume of voids over the total volume,
which is between 0 and 1, or between 0% and 100% as a percentage. Primary and secondary porosity can be
read directly from neutron, density, and sonic logs. (En.wikipedia.org, 2019) These tools do not measure
pore volume directly, rather they measure physical parameters of the formation and relate them to porosity
mathematically or empirically. (day,R,L and marsh,B,K, 1988). Below, the effective porosity is being
calculated which refers to the fraction of the total volume in which fluid flow is effectively taking place and
includes catenary and dead-end pores but excludes closed pores. This is very important for groundwater and
petroleum flow, as well as for solute transport.
3. Materials
1- Graduated cylinder
2- Water
3- Electric Balance
4- Slime
5- Bunsen burner
6- Beaker
7- Igneous Rock
4. Procedure
1. Measure the mass of the rock.
2. Measure the mass of one slime.
3. Use 2 or 3 slimes to cover the rock completely.
4. Measure the mass of the slime that was used to cover the rock completely.
5. Measure the volume of one slime, pour water into graduated cylinder, then put the slime into the
cylinder and measure the displaced water, displaced water is equal to the volume of the slime.
6. Find the density of the slime by the rule (ρ=mass of one slime / volume of one slime)
7. Use the density of the slime to find the volume of the covered slime that used to cover the rock by
knowing its mass and density (volume of all slime = mass of all slime / density of slime)
8. Put the rock covered with slime into a beaker filled with water, and measure the displaced water
which is equal to the volume of the rock covered with slime.
3. 2 | P o r o s i t y M e a s u r e m e n t
9. Subtract the slime volume from the rock covered with slime volume to get the bulk volume (rock
volume) by the rule (V bulk = V of rock covered with slime – V of slime).
10. Take out the rock’s slime, and use Bunsen burner to clear the rock from slime.
11. Put the rock into another beaker filled with water and measure the displacement water that is the
volume of the grains and the isolated pores.
12. Find porosity by that rule (φ = (Vbulk – Vgrain )/ Vbulk )
5. Calculations
Mass of the rock = 17.75g
Mass of the one slime = 9.1798g
Mass of the rock covered by slime = 55.05g
Mass of the covered slime used to cover the rock = mass of rock with slime - mass of the rock →
55.05g – 17.75g = 37.3g
Volume of one slime = displaced water = 7 cm3
Density of the slime = ρ = mass of one slime / volume of one slime = 9.1798/7 = 1.3114 g/cm3
Volume of the covered slime = mass of the covered slime / density of the slime →
37.3/1.3114 = 28.442 cm3
Volume of the rock covered with slime = displaced water = 31.55 cm3
Bulk volume = V of the rock covered with slime – V of slime = 31.55 – 28.442 = 3.108 cm3
Grain volume = displaced water = 2.5 cm3
Φ = (Vbulk – Vgrain)/ Vbulk = (3.108 – 2.5) / 3.108 = 0.19 × 100 = %19
6. Results
Rock Coated Rock One Slime Coated Slime Porosity Φ
Mass 17.75g 55.05g 9.1798g 37.3g
%19
Volume 2.5cm3 28.442cm3 7cm3 28.442cm3
Density 1.3114g/cm3 1.3114g/cm3
Table 1: Results of the experiment in a table.
4. 3 | P o r o s i t y M e a s u r e m e n t
7. Discussion
Be careful, putting the rock into a water without coating and measuring the displacement doesn't give the
volume of the bulk or the grains.
8. Conclusion
Pumic rocks usually have a porosity range between 64-85%, but human and random errors may have
occurred such as the inability to take accurate reading on the beaker. It can be said that the porosity of pumic
rock is always big because of its lithology, But that does not mean a reservoir with pumic rock is a good
reservoir, because factors such as fluid conductivity or permeability also effect too much.
9. References
Vocabulary.com. (2019). porosity - Dictionary Definition. [online] Available at:
https://www.vocabulary.com/dictionary/porosity [Accessed 19 Oct. 2019].
En.wikipedia.org. (2019). Porosity. [online] Available at: https://en.wikipedia.org/wiki/Porosity [Accessed
19 Oct. 2019].
Day, R.L. and Marsh, B.K., 1988. Measurement of porosity in blended cement pastes. Cement and Concrete
Research, 18(1), pp.63-73.