Introduction
As one of non-conventional energy resources, oil shale resources
have attracted widespread attention. It is generally thought that oil
shale is a fine-grained sedimentary rock containing significant amounts
of kerogen, from which a significant quantity of oil can be
fractionated. In oil shale, organic matter content is high (greater than
15%) and ash content is high (greater than 40%) as well. Oil shale can
burn. The oil yield of oil shale is usually more than 3.5%, and caloric
value 4.18-16.7 MJ/kg, which approximately amounts to half of the coal.
Both oil yield and caloric value are two important indicators for the
evaluation of oil shale [1-9].
The authors studied oil shale in NW China according to the
Strategic Planning of Western China Development (SPWCD) and the need of
China National Petroleum Corporation (CNPC). The locations of oil shale
in the area mainly comprise Tongchuan City-Binxian County in Shaanxi
province, Huatingxian County--Tanshanling of Tianzhu county--YaoJie of
Lanzhou City in Gansu province, Tanshan of Guyuan City-Shangxiaheyan of
Zhongwei County in Ningxia Hui Autonomous Region, Xiaoxia of Xining City
in Qinghai province, Yaomoshan and Shuimogou of Urumqi City--Loucaogou
of Changji City-Sangonghe of Fukang County in Xinjiang Uygur Autonomous
Region, and Bagemaode of Wulatehouqi County in Inner Mongolia Autonomous
Region. The total number of oil shale occurrences is 13 (Fig. 1). Oil
shale resources in Northwest China are abundant, and the total amount of
predicted resources of oil shale is at least 31,000 x [10.sup.8] t which
is equivalent to about 2000 x [10.sup.8] t of shale oil.
These areas are mostly highland, the Gobi-desert areas and drought.
In comparison to the eastern region, the economy is underdeveloped.
While with the pace of development in West China, except the Bagemaode
oil shale deposit in Wulatehouqi County (Inner Mongolia), other oil
shale deposits and mineral occurrences are located near the railway and
highway, transportation is convenient. Moreover, some oil shale deposits
mentioned above are located near large and medium cities in the area,
therefore, the development and utilization conditions would be better,
and the benefits to be acquired would also be better.
[FIGURE 1 OMITTED]
Methods and results
Investigations were made for the above 13 oil shale deposits in NW
China, and some information was obtained from literature [2, 6, 8-15].
Therefore, Table 1 includes also the data on oil shale resources studied
by others. The data on oil shale resources in the Ordos Basin are given
by the authors basing on field survey, geological mapping and analysis
for samples and logging data of oil fields [14, 15].
For identified distribution, quality, size, reserve and utilization
conditions of oil shale deposits in the area, the research has been
completed to survey field geological sections in a relatively detailed
way, by geological mapping in some standard areas and trenching exposure
in the cover area. Researches were also conducted to observe the
attitude, size, distribution and geological characteristics of oil shale
in field. For the results see Table 2. Some important specimens were
collected and sent to the Gansu Coal Quality Supervision Examine Station
for oil yield analysis and to the Test Center of Geophysical and
Chemical Exploration Research Institute, Ministry of Land and Resources,
for determination of macro, micro and rare-earth elements. Oil yield of
oil shale was determined by Engineer Liu Bingyuan using the method of
Gray-King low-temperature distillation according to the standard
GB-T1341-2007.
The results of analysis are given in Tables 3-5 and in Fig. 2
[FIGURE 2 OMITTED]
Discussion
Large resource potentials and low verification levels
Table 1 shows that the total amount of predicted resources of oil
shale in NW China is about 31,000 x [10.sup.8] t, which is equivalent to
about 2000 x [10.sup.8] t of shale oil. Oil shale resources in the Ordos
Basin account for 99% of this amount and can be compared to oil shale
resources in the Green River area of western North America. The latter
also reach about 2000 x [10.sup.8] t shale oil [9, 10]. However, the
amount of proved and controlled economic reserves (121b + 122b + 2m22)
is about 22.86 x [10.sup.8] t, which is equivalent to about 1.5 x
[10.sup.8] t shale oil (burial depth is less than 300 m). The amount of
identified resources is near to 131.56 x [10.sup.8] t. The ratio of
proved reserves of oil shale is significantly lower, and accounts only
for about 6% of the proved oil shale reserves across the country (374 x
[10.sup.8] t) [2, 6, 9].
In the Ordos Basin, the predicted, intrinsic economic resources
(334) are mainly distributed in more than 300 m under the ground [14].
The data above show that the exploration level of oil shale
deposits in the regions is low. Furthermore, oil shale is distributed
unevenly and buried deep, but demonstrates big potential of exploration
and development in these regions.
Temporal and spatial distribution of oil shale in the area
The oil shale in NW China mainly occurrs in different types of
basins from the Late Paleozoic to Mesozoic (littoral-neritic basins and
inland lakes), and generally in a shallow depth. But the oil shale in
the Ordos Basin, which formed in the Middle-Late Triassic in a
half-deep--deep lake, is buried deep, the maximum depth being nearly
2000 m.
In the Late Palaeozoic, oil shale formed mainly in the coastal
basins on the passive continental margin southwest of the palae North
China Plate and in the environment of inland lakes in the suturing zone
between the palae Tarim Plate and palae Junggar Plate (Fig. 1). The
former takes Shangxiaheyuan oil shale deposit in Zhongwei County,
Ningxia, formed in the Late Carboniferous for an example, and the later
takes Yaomoshan oil shale deposit in near Urumqi city Xinjiang, formed
in the Late Permian for an example. The environment under which they
formed was significantly different. The former formed mainly in a marine
environment and the latter in a terrestrial environment. Though the
Shangxiaheyan oil shale deposit in Zhongwei County is located in the
North Liupanshan Basin, the environment when oil shale was forming was a
coastal basin on the passive continental margin in the Late Paleozoic
[17-20]. At first, the paleo environment in which the oil shale near
Urumqi city (Jimusaer country) formed was considered to be marine, but
because later the freshwater lamellibranch was found in the oil shale
strata, then paleo environment was considered to have been terrestrial.
In the Mesozoic, oil shale mainly occurred in inland lakes after
the collision of the palae North China Plate with the palae South China
Plate. As for inland lake basins, the Ordos Basin formed mainly owing to
pushing and shoving by Indosinian movement in south. Oil shale occurring
in the Ordos Basin is also the main source rock of the superlarge Ordos
oil field [17]. But in the Jurassic and Cretaceous, the development of
inland lakes was mainly affected by subduction of the ancient Izanagi
Plate in the east side or the Tethyan oceanic Plate in the south side
[18, 19]. Tanshan oil shale formed in the Yan'an Formation in the
early stage of the Middle Jurassic, and Tongchuan oil shale (including
the oil shale which occurs in the Tongchuan oil shale peripheral region)
formed in the Yanchang Formation in the Middle-Late Triassic. Yaojie oil
shale, Tanshanling oil shale and Xiaoxia oil shale formed in the Minhe
Basin and the Xining Basin, respectively, in the early stage of the
Middle Jurassic [10, 11], and the two basins are genetically related
belonging to the same basin in the early stage of the Middle Jurassic in
essence. Bagemaode oil shale formed in Bayingobi Formation in the
north-east edge of the Suhongtu Basin, which formed in the late period
of the Early Cretaceous (Table 2).
Types of oil shale deposits and ancient environment
There are mainly three types of oil shale deposits in NW China: (i)
littoral-neritic facies sedimentary deposits in the Late Carboniferous;
(ii) residual lake bay-lake phase sedimentary deposits of the Late
Permian; (iii) inland lake system sedimentary deposits (including lake
facies and delta phase).
In the Late Carboniferous, paleoclimate in the region was
interchanging between mild--wet and dry--wet, and ancient organisms
belonged to Cathaysia Lepidodendropsis flora. In the late Permian,
paleoclimate was semi-humid, and ancient organisms included Angara
flora, ostracods, bivalves, conchostracan and freshwater lamellibranch.
In the Middle-Late Triassic, paleoclimate was hot--humid, and ancient
organisms were ginkgo, ferns, cycads, pine, conchostracan, ostracods,
bivalves, fish, and, etc. In the Middle Jurassic, paleoclimate in the
region was humid, and ancient plants were pteris, ginkgo, equisetites,
coniopteris, neocalamites and, etc. In the Early Cretaceous,
paleoclimate was alternating between dry--wet pertaining to temperate
zone to subtropical zone, and ancient plants were Coniferophyta,
Classopollis, Granodiscus, Granulatus and, etc (Table 2).
Area and thickness of oil shale beds
The areas of different oil shale deposits differ significantly. For
example, the area of oil shale deposits in the Ordos Basin was about
29,400 [km.sup.2] [14] in the Middle-Late Triassic, and exceeded 100,000
[km.sup.2] in the Middle Jurassic [5, 18], but less than 35 [km.sup.2]
in the Minhe Basin (Table 2). The area of proved oil shale reserves is
generally between 3.3 and 520 [km.sup.2] (Table 2). Oil shale monolayer
is generally thin--1-5 m, though, in the Middle-Late Triassic, in the
Ordos Basin, the main layers of oil shale were 3-36 m thick [5, 6].
Thickness of different oil shale deposits varies largely (Table 2), for
example Yaomoshan oil shale deposit in Urumqi, Xinjiang, is 71 m thick,
but only 4 m thick is the Tanshan oil shale in Ningxia.
Characteristics of oil shale samples and material composition
Oil shale is of light gray yellow, or light brown color in Eastern
China [9], but mostly brown-black or black in NW China. Oil shale in NW
China is characterized by slightly grease shiny and flaky, layered
structure with irregular-conchoidal fractures and low hardness. If
carving the surface of oil shale with a nail, you can see obvious brown
bright streaks and plant debris. Oil shale looks like a brown paper with
developed foliation and low hardness after it has been weathered, and
some brown paper-thin sheets can directly burn. The surface of oil shale
in the Tongchuan region looks maroon due to iron oxidation and is
slightly rough due to the presence of sandy minerals. Fresh oil shale
surfaces are black. In contrast to the oil shales of the other areas,
both maroon color and roughness give the oil shale in the Tongchuan
regions a certain appearance [14, 15]. The feature of layers and red
surface prove that the oil shale in the Ordos Basin formed in the
Middle-Late Triassic in inland deep water--half-deep water lake facies.
Because it contains some clastic material, the oil shale should have
been formed in a proximal material supply at setting. In microscope,
clear angular fragments of feldspar can be seen. The oil shale is
characterized by blastopelitic texture and tabular structure. It
consists mainly of clay, silt, debris and iron. Both silt and debris
contain quartz and plagioclase. Mineral part of oil shale consists of
92% clay, 3% silt and debris, and 5% iron. Mineral is lineated and of
formed tabular structure. Microstructure of aphanitic clay is less
sericitizated and is obviously orientational. Iron and aphanite fill in
the clay. Silt and debris are angular, subangular or rounded, with a .
diameter of 0.03-0.06 mm, some are about 0.15 mm, up to sand grade
level. Clay and arene gathered differently, so different composition of
layers formed and, therefore, platy cleavage in the rock developed [14,
15]. Also, one of the signs of the Black Sea model is obviously
characteristic of stratification [15].
Major and trace elements present in oil shale in the area
Abundance of macro elements, rare-earth elements and trace elements
in oil shale in NW China are shown in Tables 4, 5, and distribution
patterns of rare-earth elements are shown in Fig. 2.
From Table 4 it is clear that the main materials in oil shale
composition are Si[O.sub.2] (20.44-54.68% of the rock) and
[Al.sub.2][O.sub.3] (8.51-21.43% of the rock), both the total about
52.54% of the rock, indicating that the shale belongs to the medium ash
type [3, 7]. The share of other components is small. Ash is mostly
composed of silica and oil shale is of silica type (the standard of
silica type is 40-70% Si[O.sub.2], 8-30% [Al.sub.2][O.sub.3],
[Fe.sub.2][O.sub.3] < 20%, CaO < 20%) [3, 7]. If comparing the
Fushun oil shale (61.59% Si[O.sub.2], 23.36% [Al.sub.2][O.sub.3] [3])
with the oil shale in NW China, excluding the oil shale in the Shuimogou
district in the Junggar Basin which contains more Si[O.sub.2], the
others in NW China contain less Si[O.sub.2], [Al.sub.2][O.sub.3]. The
above indicates that the ash yield of the oil shale in NW China is
relatively low, generally less than 83%, which is the limit value of oil
shale ash content (if it exceeds the limit value, oil shale would become
"oil-bearing shale" [3]).
Study of trace elements in oil shale conduces comprehensive use of
useful elements and treatment of harmful ones, so improving the level of
oil shale utilization. It also can provide a basis for protecting the
environment. The trace element content of oil shale is given in Table 5.
The oil shale in the area contains significantly more As, Pb, and Se,
while the content of Cu, Co, Ni is equivalent or lower than abundance in
Continental crust (Taylor value) [3].
It is noteworthy that a significantly higher content of Mo, U, V of
the oil shale in the Ordos Basin indicates that there may be a certain
connection between the oil shale and large uranium deposits in the Ordos
Basin. It is suggested that as the next step there should also be a
search for molybdenum and vanadium minerals in the basin. In addition,
oil shale in Ordos Basin has a ratio of Mn/Ti equivalent to 0.01, far
less than 0.1, indicating that oil shale was deposited in a proximal
deposit environment; whereas the ratio of Sr/Ba 0.17 indicates that the
oil shale deposited in a lower-salinity lake; and the ratio of V/Ni 16
is not only related to the redox potential of water but also to the
content of organic matter, indicating that the water was rich in organic
matter and the environment was strongly reducing. In summary, the oil
shale in the Ordos Basin deposited in an strongly reducing environment
of freshwater and coastal water rich organic matter.
The distribution patterns of REE in oil shale in the areas are
consistent with the distribution patterns of REE in sedimentary rocks
formed in Post-Late Archean. Both distribution curves are parallel, and
the value of [La.sub.N]/[Yb.sub.N] is 13.6 [+ or -] 2, with Eu anomaly,
[delta]Eu value is 0.67[+ or -]0.05. Figure 2 shows that younger oil
shale strata contain progressively more REE, and distribution patterns
of rare-earth elements are similar to those of the North-American shale.
Compared with the North-American shale, the oil shale in the Ordos
Basin lacks rare-earth elements, and, compared with chondrite, it is
enriched with a significant amount of Ce (Fig. 2).
Like oil shales formed at different times and in another parts of
China, the oil shale in the Ordos Basin is characterized by high H/C and
low O/C values [10].
Some problems in the development for oil shale in Northwest China
Analysis of development conditions of oil shale paragenesis with
coal
The oil shales in Xiaoxia, Yaojie, Tanshanling, and Tanshan and
Shangxiaheyan are paragenetically related to coal beds. There are 5 m
thick good-quality oil shale layers, with 7.8-% oil yield and complete
preservation in Xiaoxia. In Yaojie, there are 31 m thick oil shale
layers in which the 4th oil layer is 4.73 m thick. In Tanshan, there are
12 m thick oil shale layers, with 200 million tonnes of industrial
reserves (121b, detected economic resources) (Tables 1 and 2). The
favorable factors of development and utilization are that oil shale can
be mined simultaneously with coal. Doing so can reduce costs and improve
mining efficiency. However, new techniques are needed because in Tanshan
and Yaojie mining has caused some damage. In the newly-mined coal area,
oil shale can be mined simultaneously with coal, and the mining depth
may be increased considerably.
Mining of oil shale deposits in environmentally protected areas
Near Urumqi city, including Shuimogou, Yaomoshan, Lucaogou,
Sangonghe, Jiucaiyuanzi, and other deposits, oil shale reserves amount
to 4 x [10.sup.8] t, and forecasting resources to 114 x [10.sup.8] t.
Thickness of oil shale layers is 47 m in Shuimogou, 71 m in Yaomoshan,
66 m in Lucaogou, and 281 m in Sangonghe with 3.69-13.7% oil yield on
average. In Tongchuan, the southern Ordos Basin, there are 9 x
[10.sup.8] t of oil shale industrial reserves (121b, detected economic
resources) with an average 6.6-% oil yield (Tables 1 and 2). Although
there are certain guaranteed reserves, many of them are located in the
area overlaid by a meadow or forest, or even in a park zone, such as
Shuimogou. Open-pit mining is unlikely, as it considers using vertical
in-situ recovery (MISR), a process jointly developed by the Occidental
Oil Shale Company and Ralph M, Parson Corporation, used in commercial
scale by Occidental companies in Colorado.
Opencast mining
In 1958, Bagemaode oil shale in Inner Mongolia was generally
investigated by Geological survey of Inner Mongolia. Afterwards, partial
drilling was done. It was shown that the Bagemaode oil shale deposit
consists of 6 single layers, altogether 50 m thick, with 8119 x
[10.sup.4] t proven reserves, 300 x [10.sup.8] t forecast resources,
with 10-15% oil yield, maximum 25% oil yield, 14.63-16.72 MJ/kg caloric
value, 49.85% volatile content (Tables 1 and 2), physical properties are
good with a high mining and utilization value. Geological structure of
the mine area is simple, thick deposit is well exposed, mine beds are
stable, with small inclination (6-8[degrees]), hydrogeological
conditions are simple, stripping ratio of 0.53 [m.sup.3]/t within 0-300
m, and therefore, opencast mining would be suitable.
Conclusions
Oil shale in NW China consists of 1-36-m single layers with stratum
distribution. Oil shale is mostly dark brown, black, at some places
having a brown-red surface and slightly greasy luster. It contains clay
minerals and silt-sized detrital minerals (feldspars and quartz) and is
characterized by medium ash, average 1.5% to 13.7% oil yield, 1.66-20.98
MJ/kg calorific value, 1.55 to 2.46 apparent gravity. Younger oil shale
strata have progressively higher REE abundances. Oil shale deposits can
be classified into mainly three types: the littoral-neritic facies
sedimentary deposits of the Middle and Late Carboniferous, remnant lake
bay-lacustrine facies sedimentary deposits of the Late Permian, and
inland lacustrine-delta facies sedimentary deposits of the Mesozoic. Oil
shale which formed in inland deep water--half deep water lacustrine
facies in the Mesozoic belongs to the major industrial type and its
origin is similar to "the Black Sea model." The oil shale
layers are also the main oil source rocks in the Ordos Basin. Oil shale
which formed in deltaic environments in the Middle and Late
Carboniferous and Jurassic are mostly paragenetically related to coal.
In the area, the total amount of predicted resources of oil shale are at
least 31,000 x [10.sup.8] t, equivalent to about 2000 x [10.sup.8] t of
shale oil, oil shale resources in the Ordos Basin account for 99% of the
total and can be compared to oil shale resources in the Green River area
of western North America. In Northwest China, identified oil shale
deposits are located in the vicinity of large and medium-sized cities,
with good development prospects. If the problems of environmental
pollution will be solved and appropriate techniques are used, immense
economic benefits can be obtained.
doi: 10.3176/oil.2011.3.03
Acknowledgements
In this paper, the author has quoted the oil shale data from the
Land and Resources Department of Shaanxi Province, Gansu Province,
Qinghai Province, as well of Inner Mongolia Autonomous Region, Ningxia
Hui Autonomous Region and Xinjiang Uygur Autonomous Region. During
working in Xinjiang, Senior engineers Zhuxia and Feng Jing have offered
various help. Moreover, Ph.D. Kurt Friehauf, Professor of Geology,
Department of Physical Sciences, Kutztown University, US, has revised
the abstract and Ph.D. Jenna Merrill the whole paper.
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Presented by E. Reinsalu
Received January 5, 2011
BAI YUNLAI (a) *, TANG HUA (b), YAN KAI (c)
(a) Northwest Geological Research Institute(NWGI), PetroChina,
Lanzhou 730020, China
(b) Xi'an Institute of Geology and Mineral Resources, 710054
Xi'an, China
(c) School of the Earth Sciences and Resources, China University of
Geosciences (Beijing ), 100086 Beijing, China
* Corresponding autor: e-mail baiy16666@sina.com
Table 1. Statistics of total resources of each occurrence
area of oil shale in Northwest China (unit x[10.sup.8]t)
Basin and Site
age
Minhe YaoJie in Lanzhou, Gansu [2, 6, 9-11]
basin- Tanshanling in Tianzhu, Gansu [2, 6, 9-11]
Xining Xiaoxia in Xining, Qinghai [2, 6, 9-11]
Basin (J-K) Whole basin
Liupanshan Shangxiaheyan in Zhongwei, Ningxia [2, 6, 9, 10]
Basin (C2) Whole basin [2, 6, 9, 10, 13]
Junggar Yaomoshan in Urumuqi, Xinjiang [2, 6, 9, 10, 12]
Basin (P) Shuimogou in Urumuqi, Xinjiang [2, 6, 9, 10, 12]
Lucaogou in Miquan, Xinjiang [2, 6, 9, 10, 12]
Jiucaiyuanzi in Jimushaer, Xinjiang [2, 6, 9, 10, 12]
Sangonghe in Fukang, Xinjiang [2,6,9,10,12]
Whole basin
Suhongtu Bagemaode in Inner Mongolia [2, 6, 9, 10]
Basin Whole basin
([K.sub.1])
Ordos Tanshan in Guyuan, Ningxia [2, 6, 9, 10, 14, 15]
Basin Tongchuan in Shannxi [2, 6, 9, 10, 14, 15]
([T.sub.2-3]) Bin county in Shaanxi [6, 9]
Whole basin
Total
Total
Resources
Basin and Potential
age mineral Detected mineral resources
resources
Detected or controlled
Resource extent basic reserve
Predicted in- Detected Controlled
trinsic economic economic
economic resources resources
resources (121b) (122b)
(334)
Minhe 10 1.8
basin- 15 2.68
Xining 5 0.45
Basin (J-K) 30
Liupanshan 10 0.04
Basin (C2) 10
Junggar 30 1.2
Basin (P) 20
30
20
14
114
Suhongtu 300 0.8
Basin 300
([K.sub.1])
Ordos 102 4
Basin 30000.92 9
([T.sub.2-3]) 280
30382.92
30836.92 4.93 15.04
Total
Resources 30991.34 (Equivalent to 2045.43 t of
shale oil, 6.6% of oil yield)
Basin and Detected mineral resources
age
Detected or controlled
basic reserve Resources
Controlled Total Inferred or
sub-economic controlled intrinsic
resources economic resources
(2m22) (333)
Minhe 1.8
basin- 2.68
Xining 0.45
Basin (J-K)
Liupanshan 0.04 4
Basin (C2)
Junggar 0.97 2.17
Basin (P) 0.97 0.97 8.8 (Controlled)
0.89 0.89
37.26
44
Suhongtu 0.8 26.5 (Inferred)
Basin
([K.sub.1])
Ordos 4 11
Basin 9
([T.sub.2-3]) 0.06 0.06
2.89 22.86 131.56
Total
Resources 30991.34 (Equivalent to 2045.43 t of
shale oil, 6.6% of oil yield)
Table 2. Main geological characteristics of oil shale deposits
in Northwest China (supplemental literature [2, 10])
Era Typical Basin type Sedimentary
deposits environment
Early Bagemode Rift- Inland lake
Cretaceous in Inner depressed
Mongolia
Middle Xiaoxia in Rift- Intermontane
Jurassic Xining depressed lake
Qinghai
Yaojie in Fault- Intermontane
Lanzhou depressed, lake
Gansu depressed
Tanshanling Fault- Intermontane
in Tianzhu depressed, lake
Gansu depressed
Tanshan in Foreland Piedmont
Guyuan basin lake
Ningxia
Middle-Late Ordos Depression Inland lake
Triassic basin
Late Permian Yaomoshan Foreland Lake-bay
in Urumqi basin
Xinjiang
Lucaogou in Foreland Lake-bay
Miquan, basin
Xinjiang
Shuimogou Foreland Lake-bay
in Changji basin
Xinjian
Late Shangxiaheya Littoral- Coastal
Carboniferous n in neritic sea
Zhongwei basin
Ningxia
Era Paleoclimatic Ancient plant
conditions combination
Early Warm zone- Coniferophyte
Cretaceous subtropical dry Classopollis
and humid Granodiscus
alternating Granulatus
transition
Middle Warm zone, Pteris Ginkgo,
Jurassic humid Coniopteris
Warm zone, Pteris Ginkgo,
humid Equisetites,
Coniopteris,
Neocalamites
Warm zone, Equisetites,
humid Coniopteris,
Neocalamites
Warm zone, Ginkgo, Ferns
humid
Middle-Late Humid and hot Ginkgo, Ferns,
Triassic Cycads, Pine,
Conchostracan,
Ostracods,
Bivalves,Fish
Late Permian Warm zone, Angara flora,
semi-humid Ostracods,
Bivalves,
Conchostracan
Freshwater
lamellibranch
Warm zone,
semi-humid
Warm zone,
semi-humid
Late Tropical and Cathaysia
Carboniferous subtropical, Lepido-
humid dendropsis
Era Character of oil shale bed
Total Thickness, m Oil yield, Area,
number of % [km.sup.2]
layers
Early 6 49.4 6 520
Cretaceous predicted
42
identified
Middle 2 4.28-6.18 7.85 5.015
Jurassic 5.06 average
4 8.35-11.36 4.6-9 19
30.73 total
2 11.6 5.98-7.98 10.375
4 4.22 11.2 300 predicted
Middle-Late 3 4-36 1.5-13.7 29000
Triassic
Late Permian 10 71 (Single 5.79-8.14 3.3
layer 2-5)
23 66.18 7.08 11.49
(Single
layer 210)
23 47 (Single 5.4-10.3 4.34
layer 210)
Late 6 8.9 4.68
Carboniferous
Era Character of oil shale bed
Burial Rank of
depth, m coexisting
coal
Early 0-200
Cretaceous
Middle 0-50 Long-flame
Jurassic coal
10-300 Long-flame
coal Non-
caking coal
10-250 Long-flame
coal
100-300 Long-flame
coal
Middle-Late 0-1800
Triassic
Late Permian 0-500
0-500
0-500
Late Anthracite coal
Carboniferous
Table 3. Analysis of macro, micro and rare-earth elements
in oil shale (made by Xu Shanfa in 2009)
Analysis technique Element
Flameless atomic absorption Au
spectrometry (AAN)
Emission spectroscopy (ES) Ag, B, Sn
Atomic fluorescence As, Ge, Hg, Sb, Se
spectrometry (AFS)
Pressed disc method-X-ray Ba, Br, Cl, Cr, Ga, Mn, Nb, Ni, P,
fluorescence spectra (XRF) Pb, Rb, Sr, Ti, CaO, [K.sub.2]O,
Si[O.sub.2], [Al.sub.2][O.sub.3],
[Fe.sub.2][O.sub.3], TS (total
sulfur)
Inductively coupled plasma Be, Bi, Cd, Co, Cs, Cu,
optical spectrographic method Li, Mo, Sc, [Na.sub.2]O, MgO
(ICP-OES)
Inductively coupled plasma- Hf, Ta, Te, Th, Ce, Dy,
mass spectrography (ICP-MS) Er, Eu, Gd, Ho, La, Lu,
Nd, Pr, Sm, Tb, Tm, Y,
Yb, In
Catalytic spectrophotometry I
(COL)
Oxidative-thermolysis-gas N, total C
chromatography
Electrometric method Organic C
Analysis technique Qualifi- Laboratory
cation
rate
Flameless atomic absorption 100% The Test Center of
spectrometry (AAN) Geophysical
and Chemical
Emission spectroscopy (ES) Exploration
Research Institute,
Atomic fluorescence Ministry of Land and
spectrometry (AFS) Resources
Pressed disc method-X-ray
fluorescence spectra (XRF)
Inductively coupled plasma
optical spectrographic method
(ICP-OES)
Inductively coupled plasma-
mass spectrography (ICP-MS)
Catalytic spectrophotometry
(COL)
Oxidative-thermolysis-gas
chromatography
Electrometric method
Table 4. Chemical composition of oil shale in Northwest
China (%)
Serial Sampling site Sample number Si[O.sub.2]
number
1 Xiaoxia, Qinghai XX-1 41.75
2 Xiaoxia, Qinghai XX-2 34.19
3 Tanshanling, Gansu TSL-1 54.68
4 Tanshanling, Gansu TSL-4 52.13
5 Yaojie, Gansu YJ-1 48.15
6 Yaojie, Gansu YJ-3 35.51
7 Bagemode, Inner Mongolia BGMD-1 41.01
8 Bagemode, Inner Mongolia BGM-2 33.06
9 Tanshan, Ningxia Tanshan-1 20.44
10 Tuangchuan, Shaaxi Tongchuan-1 52.02
Serial Sampling site [Al.sub.2][O.sub.3]
number
1 Xiaoxia, Qinghai 14.00
2 Xiaoxia, Qinghai 10.27
3 Tanshanling, Gansu 15.85
4 Tanshanling, Gansu 15.07
5 Yaojie, Gansu 21.43
6 Yaojie, Gansu 12.09
7 Bagemode, Inner Mongolia 15.44
8 Bagemode, Inner Mongolia 8.51
9 Tanshan, Ningxia 7.12
10 Tuangchuan, Shaaxi 13.42
Serial Sampling site [Fe.sub.2][O.sub.3] FeO MgO
number
1 Xiaoxia, Qinghai 3.22 1.01 0.32
2 Xiaoxia, Qinghai 3.40 1.69 0.26
3 Tanshanling, Gansu 5.88 0.17 2.24
4 Tanshanling, Gansu 4.56 0.26 2.11
5 Yaojie, Gansu 5.87 0.25 0.62
6 Yaojie, Gansu 0.16 0.57 0.24
7 Bagemode, Inner Mongolia 8.35 2.40 1.54
8 Bagemode, Inner Mongolia 0.94 2.25 0.37
9 Tanshan, Ningxia 6.36 1.50 0.83
10 Tuangchuan, Shaaxi 5.01 2.02 1.12
Serial Sampling site CaO [Na.sub.2]O [K.sub.2]O
number
1 Xiaoxia, Qinghai 0.34 0.46 1.09
2 Xiaoxia, Qinghai 1.62 0.78 0.73
3 Tanshanling, Gansu 2.07 1.15 2.68
4 Tanshanling, Gansu 4.20 1.13 2.37
5 Yaojie, Gansu 0.14 0.55 2.39
6 Yaojie, Gansu 0.09 0.08 0.98
7 Bagemode, Inner Mongolia 5.99 0.41 1.90
8 Bagemode, Inner Mongolia 0.58 0.46 0.40
9 Tanshan, Ningxia 0.27 0.27 1.12
10 Tuangchuan, Shaaxi 0.78 1.66 2.96
Serial Sampling site MnO [P.sub.2][O.sub.5]
number
1 Xiaoxia, Qinghai 0.01 0.15
2 Xiaoxia, Qinghai 0.03 0.11
3 Tanshanling, Gansu 0.04 0.40
4 Tanshanling, Gansu 0.06 0.18
5 Yaojie, Gansu 0.05 0.19
6 Yaojie, Gansu 0.00 0.00
7 Bagemode, Inner Mongolia 0.17 0.21
8 Bagemode, Inner Mongolia 0.03 0.28
9 Tanshan, Ningxia 0.013 0.05
10 Tuangchuan, Shaaxi
Serial Sampling site Ti[O.sub.2] [LOI.sup.*]
number
1 Xiaoxia, Qinghai 0.96 36.15
2 Xiaoxia, Qinghai 0.71 46.31
3 Tanshanling, Gansu 0.81 14.15
4 Tanshanling, Gansu 0.72 16.62
5 Yaojie, Gansu 0.76 18.94
6 Yaojie, Gansu 1.16 48.77
7 Bagemode, Inner Mongolia 0.92 21.14
8 Bagemode, Inner Mongolia 0.75 52.03
9 Tanshan, Ningxia 0.32 61.73
10 Tuangchuan, Shaaxi
Serial Sampling site T[Fe.sub.2][O.sub.3] C[O.sub.2]
number
1 Xiaoxia, Qinghai 4.13 1.49
2 Xiaoxia, Qinghai 5.18 1.99
3 Tanshanling, Gansu 5.78 1.00
4 Tanshanling, Gansu 4.71 1.39
5 Yaojie, Gansu 5.97 0.09
6 Yaojie, Gansu 0.80 3.80
7 Bagemode, Inner Mongolia 11.02 6.13
8 Bagemode, Inner Mongolia 3.44 0.89
9 Tanshan, Ningxia 8.01
10 Tuangchuan, Shaaxi
Serial Sampling site TS Total
number
1 Xiaoxia, Qinghai 0.45 99.46
2 Xiaoxia, Qinghai 0.20 100.10
3 Tanshanling, Gansu 0.39 100.12
4 Tanshanling, Gansu 0.30 99.41
5 Yaojie, Gansu 0.48 99.34
6 Yaojie, Gansu 0.72 99.65
7 Bagemode, Inner Mongolia 1.43 99.48
8 Bagemode, Inner Mongolia 0.09 99.66
9 Tanshan, Ningxia 0.43 100.02
10 Tuangchuan, Shaaxi 1.16
* Loss on ignition
Table 5. Trace elements and rare-earth elements in oil shale in
Northwest China (most x [10.sup.6], Au, Ag x [10.sup.9])
Trace elements
Sampling site Sample number Au Ag As Ba
Xiaoxia mining XX-1 1.8 87 38.3 466
area
XX-2 2.5 92 23.4 304
Tanshanling TSL-1 10.6 160 21.5 1018
mining area TSL-4 5.2 178 23.4 286
Yao jie mining YJ-1 4 127 17.6 267
area YJ-3 2.1 299 4.8 432
Shuimogou Shuimogou-1 1.06 74 20.5 370
Bagemaode BGMD-1 2.8 79 18 526
mining area BGM-2 2.4 49 7.7 386
Shangxiaheyan SXHY-1 4.8 107 40 630
mining area
Southern of Tongchuan II-2 3.95 171 66.0 1010
Ordos Basin Tongchuan IV-2 1.19 177 38.0 655
(Tongchuan
deposit)
Continental 4 70 1.8 390
crust
Trace elements
Sampling site Co Cu Cs Mo Ni Pb Se
Xiaoxia mining 6.9 39.4 9 2.66 25 31.4 1.0
area
9.4 31.8 5 3.11 49.9 168 1.01
Tanshanling 13.1 42.3 17.5 2.29 33.5 26.5 0.81
mining area 10.9 37.4 15.1 1.45 26.8 22.7 1.04
Yao jie mining 12.5 29.8 6.9 1.29 31.1 28.6 2.94
area 3.8 39.9 16.9 1.24 8.2 29.7 0.12
Shuimogou 13.8 56.3 6.83 2.7 62.9 15.4 0.48
Bagemaode 16.8 36.7 7 1.68 39.1 27.7 0.46
mining area 19.6 27.4 1.8 0.91 46.2 10.6 0.07
Shangxiaheyan 21.3 49.8 10.6 1.05 61.2 28.2 0.73
mining area
Southern of 1.3 71.3 7.94 79.0 6.9 29 1.38
Ordos Basin 4.6 55.7 8.68 73.0 17.3 32 0.42
(Tongchuan
deposit)
Continental 25 55 3 1.5 75 12.5 0.05
crust
Trace elements
Sampling site U V Zn Mn Ti Sr
Xiaoxia mining 5.6 43.5 65.6
area
5 30.8 85.7
Tanshanling 6.3 76 89.9
mining area 4.6 67.4 106
Yao jie mining 12.9 61.3 102
area 5.3 22.6 24.3
Shuimogou 2.13 109.2 103.2
Bagemaode 6.3 64.2 83
mining area 1.9 60 59.7
Shangxiaheyan 4.5 82.7 95.2
mining area
Southern of 36.2 183 13.1 50 2970 146.5
Ordos Basin 26.66 228 29.0 73 2855 146.8
(Tongchuan
deposit)
Continental 2.7 135 70 100 4500 340
crust
Lanthanide series
Sampling site Sample number La Ce Pr Nd Sm
Xiaoxia XX-1 31.4 50 6.5 25.6 5.1
mining area
Tanshanling TSL-1 26.8 56 6.9 27 5.7
mining area
Yao jie YJ-1 54 101 12.4 49.6 10.6
mining area
Bagemaode BGMD-1 54.4 108 13.4 52.2 10.7
mining area
Shangxiaheyan SXHY-1 42 78 9.7 35.9 6.8
mining
area
Southern of 26.31 45.05 5.14 17.28 2.72
Ordos Basin Tongchuan II-2
(Tongchuan Tongchuan IV-2 29.60 50.54 5.88 21.27 3.80
deposit)
North
American 32 73 7.9 33 5.7
shale
Chondrite 0.3 0.91 0.12 0.64 0.2
Lanthanide series
Sampling site Eu Gd Tb Dy Ho Er Tm
Xiaoxia 1.16 4.12 0.66 3.43 0.63 1.86 0.3
mining area
Tanshanling 1.2 5.28 0.93 4.85 0.94 2.74 0.45
mining area
Yao jie 2.33 9.86 1.65 9.07 1.77 5.44 0.96
mining area
Bagemaode 1.99 9.99 1.73 9.54 1.81 5.27 0.82
mining area
Shangxiaheyan 1.45 5.74 0.96 5.08 1.02 3.1 0.54
mining
area
Southern of 0.50 1.94 0.29 1.58 0.32 1.06 0.18
Ordos Basin
(Tongchuan 0.78 3.30 0.53 2.91 0.59 1.96 0.30
deposit)
North
American 1.24 5.2 0.85 6 1.04 3.4 0.5
shale
Chondrite 0.07 0.26 0.05 0.3 0.08 0.2 0.03
Lanthanide series
Sampling site Lu Sc Y
Xiaoxia 0.28
mining area
Tanshanling 0.39
mining area
Yao jie 0.8
mining area
Bagemaode 0.69
mining area
Shangxiaheyan 0.46
mining
area
Southern of 0.21 8.63 9.8
Ordos Basin
(Tongchuan 0.36 7.99 19.8
deposit)
North
American 0.48
shale
Chondrite 0.03
Note: The sample collected by Bai YunLai, Wu Wu-Jun (2005).
Analysis by The Test Center of Geophysical and Chemical
Exploration Research Institute, Ministry of Lands and Resources
(2005); the earth element abundances is Taylor value [16],
except Au, Ag in units of 10 x 10-9, other elements in unit
10 x [10.sup.-6]