Question

Question 5. Distinguish between primary, secondary and effective porosity (6 marks) Question 6. Explain the following key terms in a percolation process: Conductivity flow and Diffusivity flow (4 marks) miany

Question 5 please my teachers please

Answer 1

Q-5) A) Primary porosity:- Primary porosity is associated with the original texture of the sediment that formed during deposition. So in simple words primary porosity is the amount of empty space caused by the creation of the rock itself. It's of two type:-

(i)Primary intergranular porosity:- It's the pore space in between the detrital grains inside the depositional matrix.

(ii) Primary intragranular porosity:-It's the pore space inside fossil fragments or holes inside the mineral grains that existed before deposition.

B) Secondary porosity:- It's the porosity that developed after deposition and burial of the sediment in the sedimentary beds or due to other tectonic activity. Secondary porosity results due to dissolving of grains like fossil or shell materials, depositional material or cementitious material which bound the grains together to form the rock in early stage.

C) Effective porosity:- It's that portion of the total void space inside a porous material through which transmission of fluids take place. Effective porosity excludes isolated pores and volume of the pores occupied by adsorbed water on clay minerals or other soil grains.