Fluid Phase Behavior for Conventional and Unconventional Oil and Gas Reservoirs

4.3. Composition Retrieval

Compositions of the fluid vary significantly in some processes such as gas injection, gas–oil displacement, and gas cycling. For example, the first column of Table 4.4 gives the composition of a black oil. The composition of equilibrated phase in the first contact of a test where the 120 cm³ of a rich gas is added to 60 cm³ of the original fluid at the temperature 373K and pressure 20.79 MPa is given in the second and third column of Table 4.4. It can be seen that the composition of the original fluid varied. In these cases, the results of phase behavior prediction obtained from the group properties that were generated from the original fluid may be inaccurate. The accuracy could be improved by retrieving the fluid composition ...