12
The Chemistry and Technology of Petroleum
of oil. At this time, oil companies began to roam much farther in the search for oil, and significant
discoveries in Europe, Africa, and Canada thus resulted.
However, what is more pertinent to the industry is that throughout the millennia in which petroleum has been known and used, it is only in the last decade or so that some attempts have been made
to standardize the nomenclature and terminology. But confusion may still exist. Therefore, it is the
purpose of this chapter to provide some semblance of order into the disordered state that exists in
the segment of petroleum technology that is known as terminology.
1.3 DEFINITIONS AND TERMINOLOGY
Terminology is the means by which various subjects are named so that reference can be made in
conversations and in writings and so that the meaning is passed on.
Definitions are the means by which scientists and engineers communicate the nature of a material to each other and to the world, through either the spoken or the written word. Thus, the definition of a material can be extremely important and have a profound influence on how the technical
community and the public perceive that material.
The definition of petroleum has been varied, unsystematic, diverse, and often archaic.
Furthermore, the terminology of petroleum is a product of many years of growth. Thus, the long
established use of an expression, however inadequate it may be, is altered with difficulty, and a new
term, however precise, is at best adopted only slowly.
Because of the need for a thorough understanding of petroleum and the associated technologies, it is essential that the definitions and the terminology of petroleum science and technology be
given prime consideration (Meyer and De Witt, 1990). This will aid in a better understanding of
petroleum, its constituents, and its various fractions. Of the many forms of terminology that have
been used not all have survived, but the more commonly used are illustrated here. Particularly
troublesome, and more confusing, are those terms that are applied to the more viscous materials, for
example the use of the terms bitumen and asphalt. This part of the text attempts to alleviate much of
the confusion that exists, but it must be remembered that the terminology of petroleum is still open
to personal choice and historical usage.
Petroleum is a mixture of gaseous, liquid, and solid hydrocarbon compounds that occur in sedimentary rock deposits throughout the world and also contains small quantities of nitrogen-, oxygen-,
and sulfur-containing compounds, as well as trace amounts of metallic constituents (Bestougeff,
1967; Colombo, 1967; Thornton, 1977; Speight, 1990).
Petroleum is a naturally occurring mixture of hydrocarbons, generally in a liquid state, which
may also include compounds of sulfur nitrogen oxygen metals and other elements (ASTM D4175).
Petroleum has also been defined (ITAA, 1936) as
1. Any naturally occurring hydrocarbon, whether in a liquid, gaseous, or solid state
2. Any naturally occurring mixture of hydrocarbons, whether in a liquid, gaseous, or solid
state
3. Any naturally occurring mixture of one or more hydrocarbons, whether in a liquid,
gaseous, or solid state, and one or more of the following, that is to say, hydrogen sulfide,
helium, and carbon dioxide
The definition also includes any petroleum as defined by paragraphs (1), (2), or (3) that has been
returned to a natural reservoir.
In the crude state, petroleum has minimal value, but when refined it provides high-value liquid
fuels, solvents, lubricants, and many other products (Purdy, 1957). The fuels derived from petroleum
contribute approximately one-third to one-half of the total world energy supply and are used not
only for transportation fuels (i.e., gasoline, diesel fuel, and aviation fuel) but also to heat buildings.
The Chemistry and Technology of Petroleum
of oil. At this time, oil companies began to roam much farther in the search for oil, and significant
discoveries in Europe, Africa, and Canada thus resulted.
However, what is more pertinent to the industry is that throughout the millennia in which petroleum has been known and used, it is only in the last decade or so that some attempts have been made
to standardize the nomenclature and terminology. But confusion may still exist. Therefore, it is the
purpose of this chapter to provide some semblance of order into the disordered state that exists in
the segment of petroleum technology that is known as terminology.
1.3 DEFINITIONS AND TERMINOLOGY
Terminology is the means by which various subjects are named so that reference can be made in
conversations and in writings and so that the meaning is passed on.
Definitions are the means by which scientists and engineers communicate the nature of a material to each other and to the world, through either the spoken or the written word. Thus, the definition of a material can be extremely important and have a profound influence on how the technical
community and the public perceive that material.
The definition of petroleum has been varied, unsystematic, diverse, and often archaic.
Furthermore, the terminology of petroleum is a product of many years of growth. Thus, the long
established use of an expression, however inadequate it may be, is altered with difficulty, and a new
term, however precise, is at best adopted only slowly.
Because of the need for a thorough understanding of petroleum and the associated technologies, it is essential that the definitions and the terminology of petroleum science and technology be
given prime consideration (Meyer and De Witt, 1990). This will aid in a better understanding of
petroleum, its constituents, and its various fractions. Of the many forms of terminology that have
been used not all have survived, but the more commonly used are illustrated here. Particularly
troublesome, and more confusing, are those terms that are applied to the more viscous materials, for
example the use of the terms bitumen and asphalt. This part of the text attempts to alleviate much of
the confusion that exists, but it must be remembered that the terminology of petroleum is still open
to personal choice and historical usage.
Petroleum is a mixture of gaseous, liquid, and solid hydrocarbon compounds that occur in sedimentary rock deposits throughout the world and also contains small quantities of nitrogen-, oxygen-,
and sulfur-containing compounds, as well as trace amounts of metallic constituents (Bestougeff,
1967; Colombo, 1967; Thornton, 1977; Speight, 1990).
Petroleum is a naturally occurring mixture of hydrocarbons, generally in a liquid state, which
may also include compounds of sulfur nitrogen oxygen metals and other elements (ASTM D4175).
Petroleum has also been defined (ITAA, 1936) as
1. Any naturally occurring hydrocarbon, whether in a liquid, gaseous, or solid state
2. Any naturally occurring mixture of hydrocarbons, whether in a liquid, gaseous, or solid
state
3. Any naturally occurring mixture of one or more hydrocarbons, whether in a liquid,
gaseous, or solid state, and one or more of the following, that is to say, hydrogen sulfide,
helium, and carbon dioxide
The definition also includes any petroleum as defined by paragraphs (1), (2), or (3) that has been
returned to a natural reservoir.
In the crude state, petroleum has minimal value, but when refined it provides high-value liquid
fuels, solvents, lubricants, and many other products (Purdy, 1957). The fuels derived from petroleum
contribute approximately one-third to one-half of the total world energy supply and are used not
only for transportation fuels (i.e., gasoline, diesel fuel, and aviation fuel) but also to heat buildings.