2. P-T Diagram for Multicomponent System
• Cricondentherm (Tct)
• Cricondenbar (pcb)
• Critical point
• Bubble-point curve
• Dew-point curve
3. Oil reservoirs
• Oil reservoirs—If the reservoir temperature T is less than the critical temperature Tc of the
reservoir fluid, the reservoir is classified as an oil reservoir.
Depending upon initial reservoir pressure pi , oil reservoirs can be subclassified into the
following categories
• Undersaturated oil reservoir
• Saturated oil reservoir
• Gas-cap reservoir
Crude oils cover a wide range in physical properties and chemical compositions, and based
upon the properties exhibited, the crude oils commonly classified into the following types:
• Ordinary black oil
• Low-shrinkage crude oil
• High-shrinkage (volatile) crude oil
• Near-critical crude oil
8. Liquid shrinkage for crude oil systems
A :- Ordinary black oil
B :- Low-shrinkage crude oil
C :- High-shrinkage (volatile) crude oil
D :- Near-critical crude oil
9. Gas Reservoirs
• In general, if the reservoir temperature is above the critical temperature of the
hydrocarbon system, the reservoir is classified as a natural gas reservoir.
• On basis of their phase diagrams and the prevailing reservoir conditions, natural gases
can be classified into four categories:
• Retrograde gas-condensate
• Near-critical gas-condensate
• Wet gas
• Dry gas
