Which term refers to the rate at which fluid can flow through a rock under a given pressure gradient?

Which term refers to the rate at which fluid can flow through a rock under a given pressure gradient?

• A. Porosity
• B. Permeability
• C. Viscosity
• D. Saturation

Answer: (B)

Permeability is the ability of rock to transmit fluids. It governs how easily a fluid can flow through the interconnected pore spaces when there’s a pressure difference. In a simple sense, a rock with high permeability acts like a loose network of channels, letting fluid move quickly under the same pressure gradient, while low-permeability rock resists flow. To connect it to related concepts: porosity measures how much void space the rock has to store fluid, but not how easily that fluid can move. Viscosity is the fluid’s internal resistance to flow, so even with high permeability, a very thick fluid will move slowly. Saturation tells you how much of the pore space is filled with the fluid of interest, which affects how much fluid is available to flow but not the intrinsic rate at which flow occurs through the rock. So the term that best describes the rate at which fluid can flow through a rock under a given pressure gradient is permeability.

Permeability is the ability of rock to transmit fluids. It governs how easily a fluid can flow through the interconnected pore spaces when there’s a pressure difference. In a simple sense, a rock with high permeability acts like a loose network of channels, letting fluid move quickly under the same pressure gradient, while low-permeability rock resists flow.

To connect it to related concepts: porosity measures how much void space the rock has to store fluid, but not how easily that fluid can move. Viscosity is the fluid’s internal resistance to flow, so even with high permeability, a very thick fluid will move slowly. Saturation tells you how much of the pore space is filled with the fluid of interest, which affects how much fluid is available to flow but not the intrinsic rate at which flow occurs through the rock. So the term that best describes the rate at which fluid can flow through a rock under a given pressure gradient is permeability.