42
The Chemistry and Technology of Petroleum
It is even more confusing when an increase in boiling point is directly equated to an increase in
the number of rings. Such a system often fails to acknowledge that an increase in boiling point of
any ring compound can also (and more likely in the case of petroleum constituents) be equated to an
increase in the number or size of the substituents on the ring (Speight, 2005).
Another classification method (Burg et al., 1997) involves the use of chromatographic data.
This method evaluates the individual interactions that can take place at the molecular level to
determine the strength of these interactions. The result is the classification of crude oil on the
basis of polarity and relation of polarity to behavior. Petroleum wax has also been classified using
techniques such as gas chromatography, Fourier transform infrared spectroscopy, proton magnetic
resonance, urea adduction, and solid–liquid chromatography (Mohamed and Zaky, 2005). The
multitechnique approach used for wax reflects the potential problems that can arise for classifying
petroleum, especially when the complexity of petroleum vis-à-vis wax is considered. The multitechnique approach also indicates the lack of authenticity when no physical parameter is used to
classify petroleum.
There have also been several attempts to classify kerogen in addition to the general type classification (Chapter 5) that already exists. However, an interesting set of criteria derived from
pyrolysis-gas chromatography has shown that hydrocarbon generation can be quantified. It is also
interesting to note from this work that hydrogen deficiency in the original kerogen is not directly
equated to a low oil-producing propensity. This, and other work, will not only assist in more accurate descriptions (classification) of kerogen but also offer the potential for a more detailed description of organic facies.
In summary, any attempt to classify petroleum, heavy oil, and bitumen on the basis of a single
property is no longer sufficient to define the nature and properties of petroleum and petroleumrelated materials, perhaps being an exercise in futility. Such an attempt would be analogous to
classifying the human race on the basis of the physical characteristics of a sumo wrestler, thereby
omitting many other anthropological characteristics.
2.4 RESERVOIR CLASSIFICATION
A conventional petroleum reservoir is a dome or vault of impermeable rock, formed by folding or
faulting of the rock layers or by the rise of salt domes, with permeable rocks beneath it. In those
permeable rocks, there may be a layer of natural gas on top, with petroleum below. Beneath the oil
is usually a layer of rock soaked with water or brine. However, not all reservoirs have these characteristics and there are also unconventional or continuous reservoirs in which the oil is not trapped as
described earlier. Therefore, reservoir characterization is an essential part of petroleum technology
and offers an understanding or indication of the applicable method(s) of recovery.
2.4.1 IdentIFICAtIon And QuAntIFICAtIon
Petroleum reservoir characterization is the process of identifying and quantifying those properties of a given petroleum reservoir that affect the distribution and migration of fluids within that
reservoir. These aspects are controlled by the geological history of the reservoir. Furthermore, the
ultimate goal of a hydrocarbon reservoir characterization study is the development of a reasonable
physical description of a given reservoir. This physical description can then be used as a basis for
simulation studies, which, in turn, are used to assess the effectiveness of various recovery strategies. An accurate physical description of the reservoir often will lead to the maximum production
of hydrocarbons from the reservoir.
The type of reservoir from which it originates and the method of recovery appear to be the most
appropriate method(s) for classifying petroleum, heavy oil, and tar sand bitumen. Thus, a general
classification scheme has been developed for petroleum reservoirs contained in US Department of
The Chemistry and Technology of Petroleum
It is even more confusing when an increase in boiling point is directly equated to an increase in
the number of rings. Such a system often fails to acknowledge that an increase in boiling point of
any ring compound can also (and more likely in the case of petroleum constituents) be equated to an
increase in the number or size of the substituents on the ring (Speight, 2005).
Another classification method (Burg et al., 1997) involves the use of chromatographic data.
This method evaluates the individual interactions that can take place at the molecular level to
determine the strength of these interactions. The result is the classification of crude oil on the
basis of polarity and relation of polarity to behavior. Petroleum wax has also been classified using
techniques such as gas chromatography, Fourier transform infrared spectroscopy, proton magnetic
resonance, urea adduction, and solid–liquid chromatography (Mohamed and Zaky, 2005). The
multitechnique approach used for wax reflects the potential problems that can arise for classifying
petroleum, especially when the complexity of petroleum vis-à-vis wax is considered. The multitechnique approach also indicates the lack of authenticity when no physical parameter is used to
classify petroleum.
There have also been several attempts to classify kerogen in addition to the general type classification (Chapter 5) that already exists. However, an interesting set of criteria derived from
pyrolysis-gas chromatography has shown that hydrocarbon generation can be quantified. It is also
interesting to note from this work that hydrogen deficiency in the original kerogen is not directly
equated to a low oil-producing propensity. This, and other work, will not only assist in more accurate descriptions (classification) of kerogen but also offer the potential for a more detailed description of organic facies.
In summary, any attempt to classify petroleum, heavy oil, and bitumen on the basis of a single
property is no longer sufficient to define the nature and properties of petroleum and petroleumrelated materials, perhaps being an exercise in futility. Such an attempt would be analogous to
classifying the human race on the basis of the physical characteristics of a sumo wrestler, thereby
omitting many other anthropological characteristics.
2.4 RESERVOIR CLASSIFICATION
A conventional petroleum reservoir is a dome or vault of impermeable rock, formed by folding or
faulting of the rock layers or by the rise of salt domes, with permeable rocks beneath it. In those
permeable rocks, there may be a layer of natural gas on top, with petroleum below. Beneath the oil
is usually a layer of rock soaked with water or brine. However, not all reservoirs have these characteristics and there are also unconventional or continuous reservoirs in which the oil is not trapped as
described earlier. Therefore, reservoir characterization is an essential part of petroleum technology
and offers an understanding or indication of the applicable method(s) of recovery.
2.4.1 IdentIFICAtIon And QuAntIFICAtIon
Petroleum reservoir characterization is the process of identifying and quantifying those properties of a given petroleum reservoir that affect the distribution and migration of fluids within that
reservoir. These aspects are controlled by the geological history of the reservoir. Furthermore, the
ultimate goal of a hydrocarbon reservoir characterization study is the development of a reasonable
physical description of a given reservoir. This physical description can then be used as a basis for
simulation studies, which, in turn, are used to assess the effectiveness of various recovery strategies. An accurate physical description of the reservoir often will lead to the maximum production
of hydrocarbons from the reservoir.
The type of reservoir from which it originates and the method of recovery appear to be the most
appropriate method(s) for classifying petroleum, heavy oil, and tar sand bitumen. Thus, a general
classification scheme has been developed for petroleum reservoirs contained in US Department of