should, together with environmental authorities
and nuclear power companies, bear people’s
interests in mind and create long-term health
records to eliminate unnecessary fears. In addition, thermal pollution and electricity tariffs
should be researched, and benefits and compensation awarded.
6.6 Unconventional Gas
6.6.1 Current Developments
and Trends in Global
Unconventional Gas
(1) Definition and classification of unconventional gas
Unconventional gas refers to gas resources that
previously could not be explored and exploited
economically by conventional methods and
techniques. It is characterised by its abundance,
poor physical properties of reservoir (porosity:
less than 10%; permeability: lower than
1 Â 10
−3
lm
2 ).
Unconventional gas usually includes tight gas
(short for tight sandstone gas), shale gas, coalbed
methane and natural gas hydrate. Tight gas
means that the natural gas deposits in sandstone
(carbonatite, volcanic) strata are tighter than in
conventional reservoirs. In China, tight gas is
called low, very low or ultra-low permeability
gas. Coalbed methane refers to the gas absorbed
on the surface of coal and in micro-fissures in the
coal bed. Shale gas means that natural gas exists
in a free state in minute pores or fissures inside
the shale and adsorbed on the surface of minerals
and organics. Natural gas hydrate is a solid
crystalline compound composed of water and
natural gas formed at low temperature and high
pressure, also called combustible ice.
(2) Current developments in unconventional
gas in major countries
First, tight gas. Tight gas resources are abundant
(about 210 Â 1,012 m
3 ) across the globe and
distributed widely in Asia-Pacific, North
America, Latin America, the former Soviet
Union, the Middle East and North Africa. Survey
results from the U.S. Geological Survey show
that around 70 basins with tight gas have been
discovered in the world.
A dozen or so countries and regions, including the USA, Canada, Australia, Mexico, Venezuela, Argentina, Indonesia, China, Russia and
Egypt are exploring and exploiting tight gas
deposits. The USA and Canada are leaders in this
regard. Tight gas exploration and exploitation in
the USA started in the late 1970s when national
gas output decreased substantially, aggravating
the imbalance between supply and demand. So,
the US government introduced a series of tax
incentives and subsidy policies to encourage the
development of unconventional gas and
low-permeability gas deposits, leading to significant breakthroughs. As a result of the support
policies, tight gas became a major part of US gas
production, hitting 60 billion cubic meters
(bcm) and 100 bcm in 1990 and 1998 respectively and amounting to 175.4 bcm in 2010
(accounting for about 29% of total US gas output). Currently, in the USA, tight gas is being
developed in the Greater Green River, Denver,
San Juan, Piceance, Powder River, Uintah,
Appalachian and Anadarko basins in the Rocky
Mountains region. Canada’s tight gas is mainly
distributed in Alberta in west Canada. Canada
drilled its first industrial tight gas well in 1976.
The Hoadley and the Milk River gas fields discovered later are promising prospects for tight
gas. Some 6,400 km
2 of land have tight gas
deposits in Canada, with a geological reserve of
42.5 Â 10
12 m
3
.
Breakthroughs in key technologies are an
important driver behind the rapid development of
tight gas in North America. The comprehensive
application of horizontal well drilling, underbalanced drilling, well completion and gas reservoir
protection technologies in the 1990s boosted gas
yield sharply, resulting in rapid increases in tight
gas production in North America.
Second, shale gas. Shale gas resources have
not been evaluated worldwide yet. Most of the
volume data is estimated from existing geological information. Incomplete estimates by Rogner
Special Report 3: A Study of China’s Technology Revolution
377
and nuclear power companies, bear people’s
interests in mind and create long-term health
records to eliminate unnecessary fears. In addition, thermal pollution and electricity tariffs
should be researched, and benefits and compensation awarded.
6.6 Unconventional Gas
6.6.1 Current Developments
and Trends in Global
Unconventional Gas
(1) Definition and classification of unconventional gas
Unconventional gas refers to gas resources that
previously could not be explored and exploited
economically by conventional methods and
techniques. It is characterised by its abundance,
poor physical properties of reservoir (porosity:
less than 10%; permeability: lower than
1 Â 10
−3
lm
2 ).
Unconventional gas usually includes tight gas
(short for tight sandstone gas), shale gas, coalbed
methane and natural gas hydrate. Tight gas
means that the natural gas deposits in sandstone
(carbonatite, volcanic) strata are tighter than in
conventional reservoirs. In China, tight gas is
called low, very low or ultra-low permeability
gas. Coalbed methane refers to the gas absorbed
on the surface of coal and in micro-fissures in the
coal bed. Shale gas means that natural gas exists
in a free state in minute pores or fissures inside
the shale and adsorbed on the surface of minerals
and organics. Natural gas hydrate is a solid
crystalline compound composed of water and
natural gas formed at low temperature and high
pressure, also called combustible ice.
(2) Current developments in unconventional
gas in major countries
First, tight gas. Tight gas resources are abundant
(about 210 Â 1,012 m
3 ) across the globe and
distributed widely in Asia-Pacific, North
America, Latin America, the former Soviet
Union, the Middle East and North Africa. Survey
results from the U.S. Geological Survey show
that around 70 basins with tight gas have been
discovered in the world.
A dozen or so countries and regions, including the USA, Canada, Australia, Mexico, Venezuela, Argentina, Indonesia, China, Russia and
Egypt are exploring and exploiting tight gas
deposits. The USA and Canada are leaders in this
regard. Tight gas exploration and exploitation in
the USA started in the late 1970s when national
gas output decreased substantially, aggravating
the imbalance between supply and demand. So,
the US government introduced a series of tax
incentives and subsidy policies to encourage the
development of unconventional gas and
low-permeability gas deposits, leading to significant breakthroughs. As a result of the support
policies, tight gas became a major part of US gas
production, hitting 60 billion cubic meters
(bcm) and 100 bcm in 1990 and 1998 respectively and amounting to 175.4 bcm in 2010
(accounting for about 29% of total US gas output). Currently, in the USA, tight gas is being
developed in the Greater Green River, Denver,
San Juan, Piceance, Powder River, Uintah,
Appalachian and Anadarko basins in the Rocky
Mountains region. Canada’s tight gas is mainly
distributed in Alberta in west Canada. Canada
drilled its first industrial tight gas well in 1976.
The Hoadley and the Milk River gas fields discovered later are promising prospects for tight
gas. Some 6,400 km
2 of land have tight gas
deposits in Canada, with a geological reserve of
42.5 Â 10
12 m
3
.
Breakthroughs in key technologies are an
important driver behind the rapid development of
tight gas in North America. The comprehensive
application of horizontal well drilling, underbalanced drilling, well completion and gas reservoir
protection technologies in the 1990s boosted gas
yield sharply, resulting in rapid increases in tight
gas production in North America.
Second, shale gas. Shale gas resources have
not been evaluated worldwide yet. Most of the
volume data is estimated from existing geological information. Incomplete estimates by Rogner
Special Report 3: A Study of China’s Technology Revolution
377