A new monitoring-while-drilling method of large diameter drilling in underground coal mine and their application

Zhang, Wenlong; Li, Chen; Jin, Junxiao; Qu, Xiaohui; Fan, Shuo; Xin, Chongwei

doi:10.1016/j.measurement.2020.108840

Cited by 29 publications

(21 citation statements)

References 33 publications

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“…9 Therefore, the most fundamental way is to take out the coal to achieve pressure relief effects, and the permeability of the coal will be greatly improved after pressure relief. 10 However, the measures of pressure relief and antireflection through a large number of boreholes have huge quantities and high cost.…”

Section: Introductionmentioning

confidence: 99%

“…However, for coal seams without a protective layer or single coal seam, only other antireflection measures can be taken, for example, high-pressure hydraulic fracturing, deep-hole loose blasting, dense drilling, cross drilling, hydraulic slotting, hydraulic punching cavitation, and other antireflection measures. − However, for soft and low-permeability coal seams such as structural coal, the measures such as high-pressure hydraulic fracturing and deep-hole loose blasting are not applicable because the cracks generated by such measures are difficult to maintain in coal seam, which leads to a poor antireflection effect and the risk of inducing outburst . Therefore, the most fundamental way is to take out the coal to achieve pressure relief effects, and the permeability of the coal will be greatly improved after pressure relief . However, the measures of pressure relief and antireflection through a large number of boreholes have huge quantities and high cost.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Simulation of Integrated Mechanics of Drilling and Mechanical Cavitation in Coal Seam

Linghu

Yue

2022

ACS Omega

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For coal and gas outburst and difficult extraction in soft, low-permeability, and high-gas seam, the integration technology of drilling and mechanical cavitation is put forward to relieve pressure and improve permeability of coal seam. Through the test of mechanical parameters of the coal body, the physical model of drilling and cave-making in coal seam is established, and the mechanical characteristics of drilling and mechanical cavitation are simulated numerically. The results show that the peak strength of coal increases linearly with confining pressure. When the drill bit just touches the coal, the maximum stress occurs at the center of the coal sample. With the increase in the drilling depth of the drill bit, the maximum stress point shifts to the depth. When the coal at the center of the sample is broken, the position of the maximum stress shifts to the surrounding. With the increase of drilling depth, the maximum contact number between the drill bit and coal body increases sharply. When the bit body basically enters the coal body, the maximum contact number between the drill bit and coal body remains unchanged. When the drill pipe rotates, the reaming tool collides with the hole wall at the reaming position on the axis. In general, the contact area increases with the opening of the reaming tool, but the contact between the reaming tool and the hole wall is random. As time increases, the contact force begins to increase and then basically stabilizes; at this time the reaming tool has been fully opened.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Integrated Mechanics of Drilling and Mechanical Cavitation in Coal Seam

Linghu

Yue

2022

ACS Omega

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“…At present, research on rock bursts mainly focuses on their occurrence mechanism [ 9 ], monitoring methods [ 10 , 11 ], early warning indicators [ 10 ] and treatment measures [ 9 , 12 ]. Among the above, the occurrence mechanisms should be studied clearly first, to form the basis of follow-up monitoring, early warning and treatment measures.…”

Section: Introductionmentioning

confidence: 99%

The Revealed Mechanism of Rock Burst Based on an Innovative Calculation Method of Rock Mass Released Energy

Zhang

Feng

Shi

2022

IJERPH

Self Cite

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It is very necessary to study the mechanism of rock burst, which is related to the safe construction of many geotechnical projects. Previous studies have shown that small trigger stress will lead to large energy release, but the specific conditions that cause the release and how to quantify the energy are urgent problems to be solved. In this study, an innovative calculation method of rock mass energy release is proposed, and the calculated release energy is consistent with the monitoring results of field monitoring equipment. The revealed mechanism of rock burst reflected is that under the condition of a large-ratio pre-state stress field (mostly > 2.5), a small trigger stress field will lead to a large amount of energy release under “late butterfly shape” or “final butterfly shape” of the plastic zone. This study reveals the key factor of rock burst, which plays an important reference role for the mechanism research, subsequent monitoring and treatment method of rock burst.

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“…The existing research on the use of drilling information has been carried out, showing that the nature of coal rock will affect the drilling signal, which has a practical role in practical engineering [19][20][21][22]. Some scholars decompose and transform drilling signals and use different methods to analyze and process them, finding some practical rules of drilling signal processing [23][24][25][26]. The current research method can judge the formation information and drilling tool working state by drilling string vibration signals, but there are still some problems when judging roof information by drilling vibration signals in roadway.…”

Section: Introductionmentioning

confidence: 99%

Experiment Analysis of Drilling Feedback Signal from Simulation of Roadway Roof

Guo

Zhao

et al. 2022

Geofluids

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To simulate the condition of unstable rock formation in the stable rock formation of the roadway roof, the complete and broken rock formations on the roadway roof were simulated by superimposing and combining complete specimens and broken specimens, hence providing an appropriate way to obtain the drilling vibration signals to find regular patterns which can be used to judge the state of the rock layers. The Fourier transform analysis method and the wavelet transform analysis method are, respectively, used for the vibration signals to extract the eigenvalues of the vibration signals that are quite different in the complete layer and broken layers. Effective values, kurtosis factor, pulse factors, and gravity amplitude were used to construct the eigenvectors, which were most suitable as the basis for judging the integrity of rock formation after analysis, providing an effective way to deal with drilling signal. The wavelet threshold denoising could adaptively reduce the noise of the signals, and the unbiased likelihood estimation threshold rule had the best denoising effect. Well, through the extraction and comparison of the wavelet feature-scale entropy values, it is concluded that the wavelet analysis can be used as a reference rather than a decisive factor to determine the complete and broken layers. And more research is needed to determine the selection method of wavelet.

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A new monitoring-while-drilling method of large diameter drilling in underground coal mine and their application

Cited by 29 publications

References 33 publications

Numerical Simulation of Integrated Mechanics of Drilling and Mechanical Cavitation in Coal Seam

Numerical Simulation of Integrated Mechanics of Drilling and Mechanical Cavitation in Coal Seam

The Revealed Mechanism of Rock Burst Based on an Innovative Calculation Method of Rock Mass Released Energy

Experiment Analysis of Drilling Feedback Signal from Simulation of Roadway Roof

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