Question

Well testing is to be conducted on the bounded sandstone reservoirs as shown in the figures. All the reservoirs have the same drainage area, rock and fluid properties, and well bore conditions. Which of the following statements are CORRECT for the given reservoirs?

• A. Pseudo steady flow regime will develop first in Reservoir 1.
• B. Infinite acting behavior will stop first in Reservoir 2.
• C. Infinite acting behavior will sustain the longest in Reservoir 1.
• D. Pressure depletion will be the fastest in Reservoir 3.

Hint:

Reservoirs with wells near boundaries enter boundary-dominated flow fastest; wells centered within symmetric geometries remain in infinite-acting radial flow the longest.

Answer 1

The Correct Option is C, D

To determine which statements are correct, we must analyze how the well location and reservoir geometry affect flow regimes. All reservoirs have equal drainage area and identical rock/fluid properties, so differences arise only from geometry and well placement.
Reservoir 1: A circular reservoir with the well located at the center. Because the well is equidistant from all boundaries, the pressure wave takes the longest time to reach the reservoir boundaries. Therefore, infinite acting radial flow lasts the longest in this reservoir. This means Statement (C) is correct.
Reservoir 2: A rectangular reservoir with the well located off-center but not near a boundary. The pressure wave will reach one boundary earlier than in Reservoir 1, so infinite acting behavior ends earlier than in Reservoir 1. However, it does \textit{not} end first compared to Reservoir 3. Thus, Statement (B) is incorrect.
Reservoir 3: A rectangular reservoir with the well located very close to two perpendicular boundaries. The pressure wave reaches the boundaries very quickly. As soon as boundaries are felt, the flow transitions out of infinite acting behavior, and pressure begins to deplete more rapidly. This makes Reservoir 3 the one with the fastest pressure depletion, confirming Statement (D).
Statement (A) is incorrect because pseudo-steady state begins when all boundaries are felt; since Reservoir 1 feels boundaries the latest, it cannot enter pseudo-steady state first.
Thus the only correct statements are (C) and (D).