Which aquifer model is based on the premise that the water influx rate is directly proportional to the pressure drop between the average aquifer pressure and the pressure at the reservoir-aquifer boundary?

Which aquifer model is based on the premise that the water influx rate is directly proportional to the pressure drop between the average aquifer pressure and the pressure at the reservoir-aquifer boundary?

• A. Theis
• B. Dupuit-Forchheimer
• C. Hurst
• D. Fetkovich

Answer: (D)

The key idea is how inflow is driven by the pressure difference across the reservoir boundary and how that driving force evolves with time. In the Fetkovich model, the instantaneous water influx is proportional to the difference between the average aquifer pressure and the boundary pressure, with a time-dependent factor that blends transient diffusion behavior with a boundary-dominated (pseudo-steady) regime. This reflects the physical notion that flow is driven by Δp, but the rate response changes as the system shifts from early-time, diffusion-controlled flow to late-time, boundary-controlled flow. The other models describe flow in different ways. The Theis solution is a purely transient radial-flow description tied to pumping rate and diffusivity, not a simple direct, time-varying proportionality to a boundary pressure drop. Dupuit-Forchheimer emphasizes horizontal, quasi-steady flow in unconfined aquifers and yields relationships more about head differences in a steady-like regime than a time-evolving inflow factor. The Hurst model is a different, less direct framework for transient behavior and does not capture this specific proportionality to Δp with a time-dependent transition.

The key idea is how inflow is driven by the pressure difference across the reservoir boundary and how that driving force evolves with time. In the Fetkovich model, the instantaneous water influx is proportional to the difference between the average aquifer pressure and the boundary pressure, with a time-dependent factor that blends transient diffusion behavior with a boundary-dominated (pseudo-steady) regime. This reflects the physical notion that flow is driven by Δp, but the rate response changes as the system shifts from early-time, diffusion-controlled flow to late-time, boundary-controlled flow.

The other models describe flow in different ways. The Theis solution is a purely transient radial-flow description tied to pumping rate and diffusivity, not a simple direct, time-varying proportionality to a boundary pressure drop. Dupuit-Forchheimer emphasizes horizontal, quasi-steady flow in unconfined aquifers and yields relationships more about head differences in a steady-like regime than a time-evolving inflow factor. The Hurst model is a different, less direct framework for transient behavior and does not capture this specific proportionality to Δp with a time-dependent transition.