Which term describes the portion of porosity that allows fluid flow due to connectivity?

• A. Porosity
• B. Residual
• C. Effective Porosity
• D. Irredeemable Porosity

Answer: (C)

The key idea is that not all pore space can carry fluids—only the interconnected channels contribute to flow. Effective porosity is exactly that: the portion of the total porosity that forms a connected pathway for fluids to move; it excludes isolated pores and pores where fluids are trapped. So, even if a rock has a lot of pore space overall, if a large part isn’t connected, the amount that actually enables flow is smaller. That’s why this term best describes the flow-capable portion of porosity. Porosity is the total pore volume, including non‑connected voids; residual porosity refers to the portion that remains trapped and isn’t mobile, and irredeemable porosity is used less commonly to describe porosity that can’t be produced, not the connected flow portion.