18 PETROLEUM TECHNOLOGY, ECONOMICS, AND POLITICS
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. In fact 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. The long established use of an expression,
however inadequate it may be, is altered with difficulty, and a new
term is at best adopted slowly.
In general, the large reservoirs of light oil resources have been
exploited first because larger reservoirs are easier to find and
exploit and lighter oils are more valuable and require less energy
to extract and refine to desirable products. Therefore, over time in
mature regions, lower quality crude oil (often called heavy crude
oil) has often required the exploitation of increasingly small, deep,
and heavy offshore resources. Progressive depletion also means
that oil in older fields that once came to the surface through natural
drive mechanisms, such as gas pressure, must now be extracted
using energy-intensive secondary and enhanced technologies.
Another aspect of the quality of an oil resource is that oil reserves
are normally defined by their degree of certainty and their ease of
extraction, classed as proven, probable, possible or speculative.
In addition, there are unconventional resources such as heavy oil,
deep-water oil, tar sand bitumen (oil sand bitumen in Canada) and
shale oil that are very energy intensive and costly to exploit.
However, the true reserves of a field will be known absolutely
only on the day when it is finally abandoned — when cumulative
production is know with the highest degree of certainty and subject only to counting errors. Prior to that, reserves are known only
within a spectrum of uncertainty that should be expressed in terms
of a probability range. The traditional method, which classifies
reserves as proven, probable, or possible, tends to ignore the range
of uncertainty, giving a single number for each class of reserves.
The Securities and Exchange Commission only accepts the proven
class for financial reporting purposes.
Petroleum is found in various countries (Table 1.3) and is scattered throughout the earth's crust, which is divided into natural
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. In fact 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. The long established use of an expression,
however inadequate it may be, is altered with difficulty, and a new
term is at best adopted slowly.
In general, the large reservoirs of light oil resources have been
exploited first because larger reservoirs are easier to find and
exploit and lighter oils are more valuable and require less energy
to extract and refine to desirable products. Therefore, over time in
mature regions, lower quality crude oil (often called heavy crude
oil) has often required the exploitation of increasingly small, deep,
and heavy offshore resources. Progressive depletion also means
that oil in older fields that once came to the surface through natural
drive mechanisms, such as gas pressure, must now be extracted
using energy-intensive secondary and enhanced technologies.
Another aspect of the quality of an oil resource is that oil reserves
are normally defined by their degree of certainty and their ease of
extraction, classed as proven, probable, possible or speculative.
In addition, there are unconventional resources such as heavy oil,
deep-water oil, tar sand bitumen (oil sand bitumen in Canada) and
shale oil that are very energy intensive and costly to exploit.
However, the true reserves of a field will be known absolutely
only on the day when it is finally abandoned — when cumulative
production is know with the highest degree of certainty and subject only to counting errors. Prior to that, reserves are known only
within a spectrum of uncertainty that should be expressed in terms
of a probability range. The traditional method, which classifies
reserves as proven, probable, or possible, tends to ignore the range
of uncertainty, giving a single number for each class of reserves.
The Securities and Exchange Commission only accepts the proven
class for financial reporting purposes.
Petroleum is found in various countries (Table 1.3) and is scattered throughout the earth's crust, which is divided into natural