ABSTRACT
Petroleum reservoir fluids from a very generic standpoint broadly refer to the hydrocarbon phase and the water phase that exist under a variety of temperature and pressure conditions in subsurface formations or petroleum reservoirs. Water or specifically formation water or brine or oil field water is present in an interstitial form. However, its influence on the phase behavior and properties of hydrocarbon phase is of minor consideration,1 especially given their low mutual solubilities. Therefore, from a practical, conventional reservoir engineering perspective, the term petroleum reservoir fluids generally refers to the hydrocarbon phase in a petroleum reservoir, since it is treated independent of the water phase.1 Basic characteristics of formation waters are introduced in this chapter; however, a more detailed discussion on their properties is included in Chapter 17.
