OIL AND GAS

Question 1

Initial reservoir pressure (pi) > bubble-point pressure (pb).

Answer 1

Undersaturated Oil Reservoir:

Question 2

: Initial reservoir pressure (pi) = bubble-point pressure (pb)

Answer 2

Saturated Oil Reservoir

Question 3

: Initial reservoir pressure (pi) < bubble-point pressure (pb).

Answer 3

Gas-cap (Two-phase) Reservoir

Question 4

Gas-Oil Ratio (GOR): 200 – 700 scf/STB
Oil Gravity: 15 – 40 API
Color: Brown to Dark green

Answer 4

Ordinary Black Oil:

Question 5

Oil Formation Volume Factor: < 1.2 bbl/STB
GOR: < 200 scf/STB
Oil Gravity: < 35° API
Color: Black or deeply colored

Answer 5

Low-Shrinkage Crude Oil:

Question 6

Oil Formation Volume Factor: < 2 bbl/STB
GOR: 2,000-3,200 scf/STB
Oil Gravity: 45-55° API
Color: Greenish to orange

Answer 6

Volatile (High-Shrinkage) Crude Oil

Question 7

Oil Formation Volume Factor: ≥ 2 bbl/STB
GOR: ≥ 3,200 scf/STB

Answer 7

Near-Critical Crude Oil:

Question 8

Reservoir Temperature (T) between critical temperature (Tc) and cricondentherm (Tct).
GOR: 8,000 – 70,000 scf/STB
Condensate Gravity: > 50° API
Stock-tank liquid: Water-white or slightly colored

Answer 8

Retrograde Gas-Condensate Reservoir:

Question 9

Reservoir Temperature near critical temperature.

Answer 9

Near-Critical Gas-Condensate Reservoir:

Question 10

Reservoir Temperature above cricondentherm.
GOR: 60,000 to 100,000 scf/STB
Stock-tank Oil Gravity: > 60° API
Liquid: Water-white in color

Answer 10

Wet Gas Reservoir:

Question 11

Hydrocarbon mixture exists as a gas in reservoir and surface facilities.
Only liquid associated is water.
GOR: > 100,000 scf/STB

Answer 11

Dry Gas Reservoir: