Page 34 - Handbook of Natural Gas Transmission and Processing Principles and Practices
P. 34
FIGURE 1.2 Pressure–temperature diagram for a typical natural gas mixture.
The natural gas phase behavior is a function of the composition of the gas mixture and is strongly
6
influenced by the concentration of the heavier hydrocarbons, especially hexane plus. The presence
of heavier hydrocarbons will increase the phase envelope and failure to include them in a phase
calculation will underpredict the phase envelope. There is also an essential need for proper
characterization of the heavy ends. In fact, although some different fluid descriptions match to
some extent the behavior of the reservoir fluids at reservoir conditions, they exhibit larger
variations once surface simulators are used and the fluids are subjected to process conditions.
34
