Effect of water-based SiO2 nanofluid on surface wettability of raw coal

Zou, Quanle; Zhang, Tiancheng; Ma, Tianshu; Tian, Shixiang; Jia, Xueqi; Jiang, Zebiao

doi:10.1016/j.energy.2022.124228

Cited by 75 publications

(28 citation statements)

References 36 publications

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“…The measured residual coal seam content Figure 15: Extracted gas concentration before and after implementing hydraulic fracturing measures. 10 Geofluids was 2.95 m 3 /t~5.6 m 3 /t. The measured residual gas pressure of the coal seam was 0.10 MPa~0.41 MPa, which was lower than the threshold values stipulated in the "coal and gas outburst prevention and control regulations" and the requirements of Henan Province.…”

Section: Outburst Elimination Effectmentioning

confidence: 93%

“…The coal and gas outburst dynamics are the result of the combined effects of ground stress, gas pressure, and coal mechanical properties [1][2][3][4][5][6]; it always threatens the safety of underground production as a serious mine disaster [7][8][9][10][11][12]. In some soft outburst coal seams with low permeability in China, the coal seam has suffered from strong structural compression deformation due to the influence of multistage geological structure, and its primary structure has been damaged seriously, and the coal body strength and coal seam permeability are low [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

et al. 2022

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The No. 21 coal seam in the Zhengzhou mining area is a soft, three-layer, low-permeability coal seam prone to outbursts. The three-layer structure includes the coal seam and the roof and floor layers, which exhibit high gas contents and poor permeability. The dynamic hazards caused by coal and gas outbursts are very serious. A new permeability-increasing fracturing technique that combines hydraulic perforation and hydraulic fracturing was developed specifically for the geologic conditions of the gas-bearing No. 21 coal seam. Numerical simulations were developed to study the influence of the technique on the stress distribution and permeability of the coal around the borehole. In addition, the extracted borehole gas concentrations and extraction amounts at multiple sites were investigated before and after using the technique. The study shows that the permeability-increasing fracturing technique destroys the concentrated stress coal pillars via the development of fractures between boreholes in exposed hydraulically perforated coal. The coal stress within the zone with an effective increase in permeability decreased by 30%. Furthermore, the permeability in this zone increased by three times, and the average extracted gas concentration increased by over six times. The gas pressure in the No. 21 coal seam decreased from 1.1 MPa to 0.4 MPa, and the gas content decreased from 15.96 m3/t to 5.6 m3/t. All outburst prediction indexes measured on site did not exceed their respective limits. The technique not only effectively eliminated the dynamic hazards caused by coal and gas outbursts but also achieved efficient gas extraction in the Zhengzhou mining area.

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Section: Outburst Elimination Effectmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

et al. 2022

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“…Since the tensile strength and compressive strength of rock cannot be calibrated by this contact model at the same time, this paper only uses the uniaxial compression test results of rock to calibrate the parameters. The mechanics parameters of siltstone are calibrated, and the parameters of coal and mudstone are obtained by the engineering analogy method to match the actual material 33 . The structural plane of the model is set from the Jianshanying deformation body, considering the bedding plane and three preferred structure planes, namely, C:280°∠15°, J1:54°∠74°, J2:157°∠65°, and J3:105°∠67°.…”

Section: Test Schemementioning

confidence: 99%

Experimental study on the evolution law of mining‐induced fractures and deformation rock mass structure of gently inclined layered slope

Zhao

et al. 2022

Energy Science & Engineering

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Landslide induced by underground mining is the main type of geological disaster in Guizhou Province. The spatial position of the mined‐out area is the key factor affecting the deformation evolution of mining landslides. Three typical mining‐induced slopes in western Guizhou Province are selected to establish the engineering geological model. The orthogonal experimental design is carried out with the position of the mined‐out area relative to the slope shoulder (PM) and the slope height (SH) as variables, and the discrete element simulation test is carried out. The influence of the two variables on the evolution of overlying strata fractures and the structure of slope surface deformed rock mass is analyzed by gray relational method. The results show that under the effect of mining, the overlying strata rock on the mined‐out area gradually collapses and produces cracks through the surface. The force chain arch gradually develops from the lower part to the surface rock layer, and the slope surface rock layer is transformed from a cantilever beam embedded at one end to a multisegment articulated beam. Depending on the number of segments of the articulated beam structure, it can be divided into three categories, and the rock mass where the slope collapse occurs is mainly concentrated at the end of the multisegment articulated beam. The central subsidence of the subsidence basin, the length of the end of the articulated beam, the position of the fulcrum, and the rotation angle of the beam structure are the key indicators affecting the stability of the multisegment articulated beam. Gray relational analysis shows that PM is the primary factor to control the output of these indicators. The multiple linear regression model of gray relational degree between PM and SH was constructed, and the prediction formula of gray relational grade was obtained, which realized the multiobjective prediction of the overlying strata rock structure model under the same slope parameters. The results provide the theoretical basis for disaster prevention and mitigation of gently inclined layered mining slopes.

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“…Coalbed methane (CBM) is an associated gas produced during coal mining, 1 which is a kind of gas energy associated with coal, 2 , 3 but it is also a greenhouse gas (GHG) that causes environmental pollution. 4 , 5 In particular, large quantities of GHG are emitted during coal mining due to geomechanical instability.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Evolution of Gas Flow during Coalbed Methane Recovery to Reduce Greenhouse Gas Emission: A Case Study

et al. 2022

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Gas pre-extraction technology in a coal reservoir can not only reduce greenhouse gas (GHG) emissions but also effectively recover coalbed methane (CBM). In this work, we use a geomechanical-coupled gas flow (GCF) model to simulate and analyze the pre-extraction effect of a mining-disturbed coal seam. First, the simulation results of the GCF model are compared with field test data to verify the correctness and reliability of our model. Then, the evolution law of the stress field, permeability field, and gas flow field in the extraction process is analyzed through a case study. The results show that the first principal stress of coal in a mining area increases first and then decreases slowly and reaches the peak value at 5 m. The third principal stress increases gradually at first and becomes stable after 10 m. As the distance from the mining face increases, the permeability and gas pressure of the coal seam show continuous and asymmetric “U”-shaped and “n”-shaped distribution characteristics, respectively. In addition, the recovery effect and abnormal emission factors of CBM are discussed. This study can provide theoretical guidance for optimizing the CBM recovery effect and reducing GHG emissions during mining.

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Effect of water-based SiO2 nanofluid on surface wettability of raw coal

Cited by 75 publications

References 36 publications

Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

Permeability Enhancement Technology for Soft and Low-Permeability Coal Seams Combined with Hydraulic Perforation and Hydraulic Fracturing

Experimental study on the evolution law of mining‐induced fractures and deformation rock mass structure of gently inclined layered slope

Dynamic Evolution of Gas Flow during Coalbed Methane Recovery to Reduce Greenhouse Gas Emission: A Case Study

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