A new method of coring in coal mine: pressure-holding and continuous coring technology

Zhao, Fajun; Deng, Qigen; Fu-chang, Hao; Zuo, Wei

doi:10.1007/s10064-022-03038-7

Cited by 3 publications

(2 citation statements)

References 21 publications

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“…Previous studies have been conducted on the in situ gas content. There are two main types of in situ gas content prediction methods, namely, simulation of lost gas during coring 1,17,19,20 and pressure-holding coring. 21 The first type of method commonly tries to calculate the loss of gas during coring by building mathematical models.…”

Section: Introductionmentioning

confidence: 99%

In Situ Gas Content Prediction Method for Shale

Li,

Jiang,

Xiong

2024

ACS Omega

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Shale gas is a typical unconventional energy source and recently has received great attention around the world. Unlike conventional natural gas, shale gas mainly exists in two forms: free state and adsorbed state. Therefore, geologists have proposed the concept of gas content. The traditional calculation methods of gas content can be summarized as on-site gas desorption, logging interpretation, isothermal adsorption, and so on. However, all of the methods mentioned above have their shortcomings. In situ gas content is a new concept in the calculation of the gas content. In this paper, the in situ gas content is defined as the gas content obtained by direct measurement of core gas production through experimental or mathematical simulation of original reservoir conditions. In this work, a method to calculate the in situ gas content of shale is provided, which includes two parts: numerical simulation of the coring process and a gas content experiment. Compared with previous gas content prediction methods, this article considers the influence of the temperature field on gas content both in mathematical modeling and experiments. Then, the gas content of the Longmaxi Formation shale in the Sichuan Basin was calculated using both methods as an example. The results show that (1) the numerical model was considered to be reliable by analyzing the effects of coring speed and permeability on the loss of gas; (2) the total gas content predicted by numerical simulation of the coring process and the gas content experiment are approximately equal, with values of 5.08 m 3 /t and 4.95 m 3 /t, respectively; (3) the total gas content of the USBM method is only 4.28 m 3 /t, which is significantly lower than the above methods. In summary, this study provides an in situ gas content prediction method for shale from both mathematical modeling and experiments. The mutual verification of theory and experiment makes this method highly reliable.

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Section: Introductionmentioning

confidence: 99%

In Situ Gas Content Prediction Method for Shale

Li,

Jiang,

Xiong

2024

ACS Omega

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“…The effect of core drill design modifications on ice core drill efficiency was observed [92]. A modified pressure holding technology was used to improve core drilling in coal mines [22].…”

Section: Introductionmentioning

confidence: 99%

Predicting the overall equipment efficiency of core drill rigs in mining using ANN and improving it using MCDM

Balakrishnan¹,

Ilangkumaran²,

Sankaran³

2023

Eksploatacja i Niezawodność – Maintenance and Reliability

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In this manuscript, an attempt has been made to predict and improve the overall equipment effectiveness of core drill rigs. A combined Box–Jenkins and artificial neural network model was used to develop a three parameter model (drill pushing pressure, drill penetration rate & average pillar drill pit cycle time) for predicting effectiveness. the overall equipment efficiency of core drill rigs. The values of mean average percentage error, root mean square error, normalized root mean square error, men bias error, normalized mean biased error and coefficient of determination values were found to be 9.462%, 17.378%, 0.194, 0.96%, 0.0014 and 0.923. Empirical relationships were developed between the input and output parameters and its effectiveness were evaluated using analysis of variance. For attaining 74.9% effectiveness, the optimized values of pushing pressure, penetration rate and average pillar drill pit cycle time were predicted to be 101.7 bar, 0.94 m/min and 272 min, which was validated. Interactions, perturbations and sensitivity analysis were conducted.

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Research and Application of Sealed coring Technology in In-situ Coal Seam of Directional Long borehole in Coal mine

Tang,

Wu,

Tang

et al. 2024

Bilimsel Madencilik Dergisi

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In order to accurately obtain the gas content of in-situ coal seams in coal mines, a sealed coring technology for in-situ coal seams in coal mines has been proposed. By utilizing the pressure difference generated by high-pressure water at both ends of the piston, the piston is driven to cut off the positioning pin, which in turn drives the ball valve in the coring device to rotate, achieving the goal of cutting off and sealing the in-situ coal core. Performance tests were conducted on the sealing pressure of the coring device by opening the amount of water holes on the piston and using suspension pins of different materials, verifying the working parameters of the piston opening amount and suspension pins of different materials, providing basic data for subsequent industrial underground tests. Finally, during the industrial test underground, it was found that the gas content in the coal seam measured by closed sampling was 1.9-2.5 times higher than that of the coal seam sampled by the hole, which verified the successful design of the closed sampling device.

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A new method of coring in coal mine: pressure-holding and continuous coring technology

Cited by 3 publications

References 21 publications

In Situ Gas Content Prediction Method for Shale

In Situ Gas Content Prediction Method for Shale

Predicting the overall equipment efficiency of core drill rigs in mining using ANN and improving it using MCDM

Research and Application of Sealed coring Technology in In-situ Coal Seam of Directional Long borehole in Coal mine

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