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GOR (Gas-Oil Ratio) Trends
Production — Well Modeling
GOR can be lower, equal, or higher than Rsi depending on the reservoir type and drive mechanism
1. Depletion-Drive (Solution-Gas Drive) Reservoirs
When pressure drops below Pb → gas evolves → flows with oil.
GOR increases above Rsi.
Eventually, GOR can peak, then decline as oil rate drops faster.
✅ GOR > Rsi (typical behavior)
2. Water-Drive Reservoirs
Pressure may stay near bubble point longer.
Less gas liberation.
GOR may remain close to Rsi or even below Rsi if gas is trapped or segregated.
✅ GOR ≈ Rsi or GOR < Rsi
3. Gas-Cap Drive Reservoirs
If gas cap is produced → very high GOR.
If only oil zone is produced → GOR may increase moderately.
GOR can be much higher than Rsi depending on coning or breakthrough.
✅ GOR > Rsi (if gas cap coning occurs)
4. Heavy Oil Reservoirs
Low Rsi to begin with.
Gas mobility is low.
GOR can remain low or increase slowly.
✅ GOR may stay ≤ Rsi for long time
1. Depletion-Drive (Solution-Gas Drive) Reservoirs
When pressure drops below Pb → gas evolves → flows with oil.
GOR increases above Rsi.
Eventually, GOR can peak, then decline as oil rate drops faster.
✅ GOR > Rsi (typical behavior)
2. Water-Drive Reservoirs
Pressure may stay near bubble point longer.
Less gas liberation.
GOR may remain close to Rsi or even below Rsi if gas is trapped or segregated.
✅ GOR ≈ Rsi or GOR < Rsi
3. Gas-Cap Drive Reservoirs
If gas cap is produced → very high GOR.
If only oil zone is produced → GOR may increase moderately.
GOR can be much higher than Rsi depending on coning or breakthrough.
✅ GOR > Rsi (if gas cap coning occurs)
4. Heavy Oil Reservoirs
Low Rsi to begin with.
Gas mobility is low.
GOR can remain low or increase slowly.
✅ GOR may stay ≤ Rsi for long time