There exists a limiting gas-liquid ratio where the decrease in hydrostatic pressure will be offset by what?

There exists a limiting gas-liquid ratio where the decrease in hydrostatic pressure will be offset by what?

• A. Increase in frictional pressure drop
• B. Increase in reservoir temperature
• C. Increase in gas viscosity
• D. Decrease in oil saturation

Answer: (A)

The main idea is how pressure losses along a wellbore balance out when gas comes out of solution. As the gas-liquid ratio rises, the liquid column becomes lighter, so the hydrostatic pressure grade decreases. But the flow becomes two-phase with more gas, which increases the frictional pressure losses along the tubing because the mixture flows with greater resistance. At a certain gas-liquid ratio, the extra frictional drop exactly offsets the drop in hydrostatic pressure, creating a limiting condition where further increases in gas do not reduce the bottom‑hole pressure. So the offset comes from an increase in frictional pressure drop. Increasing reservoir temperature or increasing gas viscosity would affect fluid properties, but they don’t describe the balancing mechanism as directly. Decreasing oil saturation affects relative permeability more than the pressure balance in this context.

The main idea is how pressure losses along a wellbore balance out when gas comes out of solution. As the gas-liquid ratio rises, the liquid column becomes lighter, so the hydrostatic pressure grade decreases. But the flow becomes two-phase with more gas, which increases the frictional pressure losses along the tubing because the mixture flows with greater resistance. At a certain gas-liquid ratio, the extra frictional drop exactly offsets the drop in hydrostatic pressure, creating a limiting condition where further increases in gas do not reduce the bottom‑hole pressure. So the offset comes from an increase in frictional pressure drop.

Increasing reservoir temperature or increasing gas viscosity would affect fluid properties, but they don’t describe the balancing mechanism as directly. Decreasing oil saturation affects relative permeability more than the pressure balance in this context.