58 PETROLEUM TECHNOLOGY, ECONOMICS, AND POLITICS
Speight, 2007b). In fact, associated natural gas is believed to be the
most economical form of ethane (Farry, 1998). Natural gas has no
distinct odor and the main use is for fuel, but it can also be used to
make chemicals and liquefied petroleum gas.
At the time of writing, world natural gas reserves are on the
order of 6.6 quadrillion cubic feet (6.6 x 10
15
cubic feet), of which
the United States has 244.7 trillion cubic feet (244.7 x 10
12
cubic
feet) or 3.7% of the total world reserves (BP, 2010).
It should also be remembered that the total gas resource base, like
any fossil fuel or mineral resource base, is dictated by economics.
Therefore, when resource data is quoted, some attention must be
given to the cost of recovering those resources. Most importantly,
the economics must also include a cost factor that reflects the willingness to secure total, or a specific degree of, energy independence.
Two new and possibly large sources of methane that can be
expected to extend the availability of natural gas are methane
hydrates (also called gas hydrates) and coal bed methane (Berecz
and Balla-Achs, 1983; Sloan, 1997; Gudmundsson et al, 1998; Max,
2000; Sloan, 2000). Their production technologies have only recently
been developed and these sources are now becoming economically
competitive.
Methane-rich gases are also produced by the anaerobic decay of
non-fossil organic material and are referred to as biogas. Sources of
biogas include swamps, marshes, and landfills, as well as sewage
sludge and manure (Speight, 2008).
Natural gas is a vital component of the world's supply of energy
and it is one of the cleanest, safest, and most useful of all energy
sources. However, it needs to be understood that the word gas has
a variety of different uses, and meanings. Fuel for automobiles is
also called gas (being a shortened version of gasoline) but that is
a totally different fuel. The gas used in a barbecue grill is actually
propane (C,H g ), which, while closely associated with and commonly found in natural gas and petroleum, is not really natural gas.
2.6.3 Heavy Oil
Thus, the generic term heavy oil is often applied inconsistently
to petroleum that has an API gravity of less than 20°(Chapter 1).
Other definitions classify heavy oil as having API gravity less than
22°API, or less than 25°API, and usually, but not always, sulfur
content higher than 2% by weight (Ancheyta and Speight, 2007).
Speight, 2007b). In fact, associated natural gas is believed to be the
most economical form of ethane (Farry, 1998). Natural gas has no
distinct odor and the main use is for fuel, but it can also be used to
make chemicals and liquefied petroleum gas.
At the time of writing, world natural gas reserves are on the
order of 6.6 quadrillion cubic feet (6.6 x 10
15
cubic feet), of which
the United States has 244.7 trillion cubic feet (244.7 x 10
12
cubic
feet) or 3.7% of the total world reserves (BP, 2010).
It should also be remembered that the total gas resource base, like
any fossil fuel or mineral resource base, is dictated by economics.
Therefore, when resource data is quoted, some attention must be
given to the cost of recovering those resources. Most importantly,
the economics must also include a cost factor that reflects the willingness to secure total, or a specific degree of, energy independence.
Two new and possibly large sources of methane that can be
expected to extend the availability of natural gas are methane
hydrates (also called gas hydrates) and coal bed methane (Berecz
and Balla-Achs, 1983; Sloan, 1997; Gudmundsson et al, 1998; Max,
2000; Sloan, 2000). Their production technologies have only recently
been developed and these sources are now becoming economically
competitive.
Methane-rich gases are also produced by the anaerobic decay of
non-fossil organic material and are referred to as biogas. Sources of
biogas include swamps, marshes, and landfills, as well as sewage
sludge and manure (Speight, 2008).
Natural gas is a vital component of the world's supply of energy
and it is one of the cleanest, safest, and most useful of all energy
sources. However, it needs to be understood that the word gas has
a variety of different uses, and meanings. Fuel for automobiles is
also called gas (being a shortened version of gasoline) but that is
a totally different fuel. The gas used in a barbecue grill is actually
propane (C,H g ), which, while closely associated with and commonly found in natural gas and petroleum, is not really natural gas.
2.6.3 Heavy Oil
Thus, the generic term heavy oil is often applied inconsistently
to petroleum that has an API gravity of less than 20°(Chapter 1).
Other definitions classify heavy oil as having API gravity less than
22°API, or less than 25°API, and usually, but not always, sulfur
content higher than 2% by weight (Ancheyta and Speight, 2007).