Which reservoir type has the predominant producing mechanism defined as fluid expansion?

Which reservoir type has the predominant producing mechanism defined as fluid expansion?

• A. Primary Recovery Reservoir
• B. Water Flood Reservoir
• C. Depletion Drive Reservoir
• D. Gas Cap Drive Reservoir

Answer: (C)

In a depletion-drive reservoir, the energy that pushes oil to the well comes from the fluids themselves as reservoir pressure falls. When production draws pressure down, the remaining oil and any dissolved gas expand. This expansion creates the natural push that drives oil toward the wellbore, making fluid expansion the dominant producing mechanism. There’s no external influx of water (as in a waterflood) and the gas-cap expansion isn’t the primary driver for most depletion-drive cases, whereas primary recovery encompasses multiple natural-energy processes. So, the mechanism most characterizing this type is the expansion of the remaining fluids as pressure declines.

In a depletion-drive reservoir, the energy that pushes oil to the well comes from the fluids themselves as reservoir pressure falls. When production draws pressure down, the remaining oil and any dissolved gas expand. This expansion creates the natural push that drives oil toward the wellbore, making fluid expansion the dominant producing mechanism. There’s no external influx of water (as in a waterflood) and the gas-cap expansion isn’t the primary driver for most depletion-drive cases, whereas primary recovery encompasses multiple natural-energy processes. So, the mechanism most characterizing this type is the expansion of the remaining fluids as pressure declines.