Reservoir Analysis

The main aim of reservoir characterization is to build an all-round understanding of petrophysical properties. The goal of this essay is to understand the laboratory measurements and basic definitions of the petrophysical properties porosity, permeability, relative permeability, capillarity, and saturation. Pore-size distribution is presented as the common link between these properties.

Rock and fluid properties are the building blocks in any reservoir engineering study that lead to the formulation of a successful reservoir management strategy. Sometimes the study involves the estimation of oil and gas reserves based on a simple analytical approach, as demonstrated in this chapter. On a separate note, performance prediction of oil and gas reservoir is done by multidimensional simulation models and robust multiphase. Regardless of the study and related complexity, the reservoir engineer must have a sound understanding of the rock properties involved. What is more important is the knowledge of the variability of rock properties throughout the reservoir and how heterogeneous reservoirs perform in the real world. It is a common observation that rock properties vary from one location to another in the reservoir, often impacting reservoir performance. Some reservoir analyses are based on the assumption that a reservoir is homogeneous and isotropic, implying that the rock properties are nonvariant and uniform in all directions. In fact these conditions are so idealized that are rarely met in the field. Various geologic and geochemical processes leave imprints on a reservoir over millions of years, leading to the occurrence of reservoir heterogeneities that are largely unknown prior to oil and gas production. For example, the occurrence...

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...n be derived from empirical relationships with other measurements such as porosity, NMR and sonic logging.

Rock thickness will have enough permeability to transcend fluids towards a bore well. This characteristic is usually called as “Net reservoir rock.” In the oil and gas industry, another quantity “Net Pay” is computed which is the rock thickness which can transcend hydrocarbons to the bore well at an optimum rate. Reservoir models are built upon their measured and derived properties to estimate the amount of hydrocarbon present in the reservoir, the rate at which that hydrocarbon can be produced to the Earth’s surface through wellbores and the fluid flow in rocks. As far as Industry of Water Resources is concerned, likewise models are utilized to analyse amount of water that can be produced to the surface over long periods of time, without depleting the aquifer.