2
Origin and Occurrence of Oil
Petroleum has been used as an energy resource for more than 6,000
years (Chapter 1) and it is by far the most commonly used source
of energy, especially as the source of liquid fuels and use of petroleum is projected to continue at least in current amounts for at
least two decades (Speight, 2007a; BP, 2008; World Energy Council,
2008; Speight, 2011) (Figure 2.1). In recent years, the average quality of crude oil has become worse. This is reflected in a progressive
decrease in API gravity (i.e., increase in density) and a rise in sulfur
content (Swain, 1991,1993,1997,2000). It is now believed that there
has been a recent tendency for the quality of crude oil feedstocks to
stabilise. Be that as it may, the nature of crude oil refining has been
changed considerably.
The declining reserves of light crude oil have resulted in an
increasing need to develop options to upgrade the abundant supply of known heavy oil reserves. In addition, there is considerable
focus and renewed efforts on adapting recovery techniques to the
production of heavy oil and tar sand bitumen (Speight, 2007a).
Fossil fuels are those fuels, namely coal, petroleum (including
heavy oil and bitumen), natural gas, and oil shale produced by the
31
An Introduction to Petroleum Technology, Economics, and Politics
by James G. Speight
Copyright © 2011 Scrivener Publishing LLC.
Origin and Occurrence of Oil
Petroleum has been used as an energy resource for more than 6,000
years (Chapter 1) and it is by far the most commonly used source
of energy, especially as the source of liquid fuels and use of petroleum is projected to continue at least in current amounts for at
least two decades (Speight, 2007a; BP, 2008; World Energy Council,
2008; Speight, 2011) (Figure 2.1). In recent years, the average quality of crude oil has become worse. This is reflected in a progressive
decrease in API gravity (i.e., increase in density) and a rise in sulfur
content (Swain, 1991,1993,1997,2000). It is now believed that there
has been a recent tendency for the quality of crude oil feedstocks to
stabilise. Be that as it may, the nature of crude oil refining has been
changed considerably.
The declining reserves of light crude oil have resulted in an
increasing need to develop options to upgrade the abundant supply of known heavy oil reserves. In addition, there is considerable
focus and renewed efforts on adapting recovery techniques to the
production of heavy oil and tar sand bitumen (Speight, 2007a).
Fossil fuels are those fuels, namely coal, petroleum (including
heavy oil and bitumen), natural gas, and oil shale produced by the
31
An Introduction to Petroleum Technology, Economics, and Politics
by James G. Speight
Copyright © 2011 Scrivener Publishing LLC.