LNG Book

Petroleum fluids for Subsea Wells

Main Petroleum Components

Natural Gas Compositions

[table id=22 /]

Reservoir considerations

  • Oil and gas reservoirs formed in porous sedimentary rock many millions of years ago.
  • Some reservoirs are close to the earth’s surface whilst others are deep in the formation.
  • Some have very high pressure and temperatures whilst other do not.
  • The range of hydrocarbons varies, as does their concentration.
  • Need to classify !!

– Phase behavior: compositions

– Fluid characteristics: API gravity

– Reservoir flow characteristics: phase diagram

Phase behavior – Pure component

Phase behavior – Multicomponents

  • Reservoir fluids have a huge number of components.
  • Their phase behavior is complex compared to single components.
  • Instead of a single curve separating liquid from vapor phases, there is a broad region where both vapor and liquid exist .
  • The two-phase region is bounded on one side by the dew point curve and on the other side by the bubble point curve.
  • The critical point is where the two curves meet

Phase behavior – Natural Gas

Multicomponent Phase Diagram

Fluid characteristics

[table id=20 /]

Black oil phase diagram


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