TABLE OF CONTENTS Properties of petroleum fluids must be quantified in a reservoir simulator. The range of applicability of a reservoir simulator is defined, in part, by the types of fluids that can be modeled using the mathematical algorithms coded in the simulator. This chapter discusses the general types of fluids that may be encountered in a commercial reservoir environment and that are suitable for flow modeling. For additional information, see Amyx, et al. [1960], Pedersen, et al. [1989], Koederitz, et al. [1989], McCain [1990, 1991], Towler [2002], and Walsh and Lake [2003].
The elemental composition (by mass) of petroleum is approximately 84% to 87% carbon, 11% to 14% hydrogen, 0.6% to 8% sulphur, 0.02% to 1.7% nitrogen, 0.08% to 1.8% oxygen, and 0% to 0.14% metals. The composition of petroleum shows that petroleum fluids are predominantly hydrocarbons. The most common hydrocarbon molecules are paraffins, napthenes, and aromatics because of the relative stability of the molecules. A paraffin is a saturated hydrocarbon, that is, it has a single bond between carbon atoms. Examples include methane and ethane. Paraffins have the general chemical formula C nH 2 n+ 2. Napthenes are saturated hydrocarbons with a ringed structure, as in cyclopentane. They have the general chemical formula C nH 2 n. Aromatics are unsaturated hydrocarbons with a ringed structure that have multiple bonds between the carbon atoms as in benzene. The unique ring structure makes aromatics relatively stable and nonreactive.
A general fluid property diagram of a...
