scholarly journals Occurrence of Irreducible Water and Its Influences on Gas-Bearing Property of Gas Shales From Shallow Longmaxi Formation in the Xishui Area, Guizhou, Southern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian Sun ◽  
Xianming Xiao ◽  
Qiang Wei ◽  
Peng Cheng ◽  
Hui Tian

Systematic studies are quite rare on the gas-bearing property and its controlling factors of the shallow Longmaxi shale outside the Sichuan Basin. In a previous study, the gas in place contents of a suit of Longmaxi shale samples with a depth range of 362–394 m from the well XK2, which was drilled in the Xishui area, Guizhou, southern China, were reported. In the present study, the pore structure parameters and irreducible water occurrence characteristics of those samples, and their influences on the gas-bearing property were further investigated. The results show that, compared to the dry sample, the non-micropore specific surface areas and micropore volumes of the moist sample are significantly reduced by an average value of 61 and 30%, respectively, and that the water averagely occupies 82 and 41% of the inorganic and organic non-micropore specific surface areas, respectively, and 44 and 18% of the inorganic and organic micropore volumes, respectively. The shallow shale reservoir is dominated by adsorbed gas. It accounts for 66–93% of the total gas. The water significantly decreases the adsorption capacity of the inorganic matte (mainly clay minerals) pores, but has a limited influence on that of the organic matter pores. The adsorbed gas occurs mostly in the organic matter nanopores, and even if the shales were highly saturated with the water, they can still store a certain amount of the adsorbed gas. These results are to provide some guides for the evaluation and exploration of the shallow Longmaxi shale located in the strongly tectonic transformation areas of southern China.

Soil Science ◽  
1992 ◽  
Vol 153 (4) ◽  
pp. 293-299 ◽  
Author(s):  
CHRISTIAN FELLER ◽  
ELISABETH SCHOULLER ◽  
FABIEN THOMAS ◽  
JAMES ROUILLER ◽  
ADRIEN J. HERBILLON

Clay Minerals ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 437-448 ◽  
Author(s):  
S. Kumpulainen ◽  
M.-L. Räisänen ◽  
F. Von Der Kammer ◽  
T. Hofmann

AbstractThe transformation of schwertmannite to goethite was studied by ageing one synthetic and five natural schwertmannites in water at room temperature. Additionally, one synthetic and two natural schwertmannites were kept at variable pH (2, 4, 6 and 8). After one year, only the synthetic sample and one natural schwertmannite had transformed to goethite. However, the oxalate solubility of Fe and trace elements in all the samples decreased, whereas the total Fe/S ratios and specific surface areas of all samples increased. Arsenic and organic matter appeared to suppress the schwertmannite-to-goethite phase transformation. At pH 2, synthetic schwertmannite fully-transformed to goethite, but at pH 4–6 only minor transformation occurred. Depending on pH, many trace elements were released into solution during ageing of the natural schwertmannites. In general, Co, Mn, Zn and Si were released to solution, whereas As was enriched in the remaining iron oxide fraction. Al was dissolved at pH <4.


2019 ◽  
Vol 8 (3) ◽  
pp. 38
Author(s):  
Weldi Gnowe Djonga ◽  
Eric Noubissié ◽  
Inna Samomssa ◽  
Guy Bertrand Noumi

The treatment of slaughterhouse effluents is a problem for our municipalities and residents. The objective of this work is to contribute to the protection of the environment through a test treatment of the effluent from the slaughterhouse of cows by adsorption on adsorbents made from sawdust. To achieve this, two adsorbents were produced based on sawdust of Ayous (Triplochiton scleroxilon) and Iroko (Milicia excelsa), and were characterized. The effluent was sampled in a Ngaoundéré slaughterhouse and then characterized in its turn. Finally, discolouration tests by adsorption of this effluent were carried out. At the end of this work, it appears that both adsorbents produced had an acidic character. They are micro and macroporous with specific surface areas from 14.77 m2/g to 69.56 m2/g for Iroko and Ayous, respectively. The effluent from the slaughterhouse of cows sampled in the city of Ngaoundéré is highly conductive and turbid with an organic matter evaluated at 4.15 ± 0.18%. The adsorbent based on sawdust of Ayous is more effective, globally allowed the reduction of more than 70% of all the organic and inorganic loads of the slaughterhouse effluent after treatment. A discolouration rate estimated at more than 90% obtained at the scale of the laboratory, these adsorbents are effective for the treatment of the slaughterhouse effluents. These two adsorbents can therefore be used for the treatment of slaughterhouse effluent in any country in the world.


Author(s):  
Robert E. White

Minerals and organic matter comprise the solid phase of the soil. The geological origin of the soil minerals, and the input of organic matter from plants and ani­mals, are briefly discussed in section 1.2.1. A basic knowledge of the composition and properties of these materials is fundamental to understanding how a soil in­fluences the growth of grapevines. A striking feature of soil is the size range of the mineral matter, which varies from boulders (>600 mm diameter), to stones and gravel (600 to >2 mm diameter), to particles (<2 mm diameter)—the fine earth fraction. The fine earth fraction is the most important because of the type of miner­als present and their large surface areas. The ratio of surface area to volume de­fines the specific surface area of a particle. The smaller the size of an object, the larger is the ratio of its surface area to volume. This can be demonstrated by con­sidering spherical particles of radius 0.1 mm, 0.01 mm, and 0.001 mm (1 mi­crometer or micron, μm). The specific surface areas of these particles are 30, 300, and 3000 mm2/mm3, respectively. In practice, the specific surface area is mea­sured as the surface area per unit mass, which implies a constant particle density (usually taken as 2.65 Mg/m3). A large specific surface area means that more mol­ecules can be adsorbed on the surface. Representative values for the specific sur­face areas of sand, silt, and clay-size minerals are given in table 2.1. Note the large range in specific surface area, even for the clay minerals, from as little as 5 m2/g for kaolinite to 750 m2/g for Na-montmorillonite. Because specific surface areas are important, we need to know the size distri­bution of particles in the fine earth fraction. This is expressed as the soil’s texture. The types of minerals that make up the individual size fractions are also impor­tant because they too influence the reactivity of the surfaces. Both these topics are discussed here. All soils show a continuous distribution of particle sizes, called a frequency dis­tribution. This distribution relates the number (or mass) of particles of a given size to their actual size, measured by the diameter of an equivalent sphere.


RSC Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 1253-1259 ◽  
Author(s):  
Jing Lin ◽  
Lulu Xu ◽  
Yang Huang ◽  
Jie Li ◽  
Weijia Wang ◽  
...  

Ultrafine porous boron nitride nanofibers with high aspect ratios, high specific surface areas and large pore volumes has been synthesized in large quantity via a freeze-drying and post pyrolysis process.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Gang Zhou ◽  
Han Qiu ◽  
Qi Zhang ◽  
Mao Xu ◽  
Jiayuan Wang ◽  
...  

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.


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