Basic Reservoir Management

A: Option A ties the symptoms together: stable BHP with early water points to near-wellbore vertical communication and coning driven by drawdown. Option B explains water, but edge-water usually shows pressure support and a slower ramp. Option C fits decline but not the rapid water cut shift. Option D happens in the field, but it doesn’t create true water production; it just distorts measured rates.

A: Option A runs the back-of-envelope: fractional depletion of 5% per year divided by total compressibility lands in the few‑tens of psi range. Option B drops rock and water compressibility, a common shortcut that breaks at reservoir scale. Option C feels safe but throws away most of the storage term, overshooting badly. Option D ignores how stiff oil-rock systems actually are; small fractional withdrawals still move pressure.

A: Option A follows Archie as written: Sw^n = (a·Rw)/(Rt·φ^m). Option B is the trap of linear intuition; Archie is exponential for a reason. Option C sneaks in default exponents that don’t match the stated rock. Option D reads the log qualitatively and skips the math, which is how saturation errors creep into models.

A: Option A fits the whole picture: bad recombination pushes bubble point high on paper while the reservoir is already two‑phase. Option B explains numbers but not surface gas. Option C creates short-lived effects, not consistent free gas. Option D sounds thermodynamic, but realistic temperature shifts won’t move bubble point by hundreds of psi.

A: Option A lines up with Darcy flow when thickness and viscosity are accounted for. Option B quietly drops h from the equation. Option C keys only on rate and forgets viscosity and radius. Option D equates high drawdown with tight rock, missing the geometric terms that dominate.

A: Option A matches the trio of declining rate, rising GOR, and fast pressure loss. Option B would show pressure support before water. Option C stabilizes pressure longer. Option D exists, but it rarely dominates unless flagged by geomechanics and subsidence data.

A: Option A respects scale: cores miss fractures, stress paths, and fluid interaction captured by field data. Option B trusts lab precision over representativeness. Option C feels balanced but has no physical basis. Option D bakes optimism into forecasts, a quiet risk in depletion planning.

A: Option A fits early GOR sensitivity without full pressure support. Option B would buffer pressure more strongly. Option C ignores how fast GOR moves with minimal depletion. Option D introduces water that simply isn’t there.

A: Option A closes the balance with both oil and gas terms on a consistent reservoir-volume basis. Option B drops the gas contribution entirely. Option C double-counts gas expansion as oil support. Option D assumes the gas cap vanished, a leap that contradicts the stated volumes.