Environmental Engineering Reference
In-Depth Information
Table 1 China gas shale depositional settings and their distribution in time and
space.
Depositional
setting
Age and formation
Distribution area
Lacustrine
Cenozoic
Neogene
Qaidam Basin
Paleogene
Bohai Bay Basin, Qaidam
Basin
Mesozoic
Cretaceous
Songliao Basin
Jurassic
Turpan-Hami, Junggar,
Tarim, Qaidam,
Sichuan Basin
Triassic
Ordos Basin, Sichuan
Basin
Paleozoic
Late Permian
Junggar, Turpan-Hami
Transitional
(coastal setting
associated with
coal)
Paleozoic
Late Permian
(Longtan Fm)
Yangtze Platform
including Sichuan in
Upper Yangtze
Early Permian
(Taiyuan,
Shanxi Fm)
North China
Late Carboniferous
(Benxi Fm)
North China
Marine
Paleozoic
Early Silurian
(Longmaxi Fm)
Yangtze Platform
including Sichuan in
Upper Yangtze
Late Ordovician
(Wufeng Fm)
Yangtze Platform
including Sichuan in
Upper Yangtze, Tarim
Basin
Early Cambrian (e.g.
Qiongzhusi Fm)
Yangtze Platform, Tarim
Basin
Pre-Cambrian
Sinian (e.g.
Doushantuo Fm)
Upper and Middle
Yangtze Platform
stratigraphic intervals are important in China. The unconventional shale gas
reserves in China are ten times greater than the current proven conventional
gas reserves. These huge shale gas resources represent a vast, long-term and
very important energy source for China, which suggests there is a great
opportunity to emulate the shale gas revolution in the U.S.
Geological investigations for resource assessment and exploration show
that organic-rich marine shales in China have good shale gas play potentials
based on high organic matter content, high maturity, high content of brittle
minerals (see Figure 2) and high intra-organic nano-porosity (see Figure 3).
For example, the Qiongzhusi shale of the Lower Cambrian in Yangtze Plat-
form, including the Sichuan Basin, has an average thickness of 120 metres
over the region with average total organic carbon (TOC) of 2.8% and average
vitrinite reflectance (Ro, a measure of the thermal history of hydrocarbon
source sediments) of 3%. The Longmaxi formation shale of the Lower
Silurian has an average thickness of 100 metres across the region with an
average TOC of 2.6% and Ro between 2% and 3%. Both of these two typical
 
 
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