scholarly journals Nitrogen Injection To Flush Coal Seam Gas Out Of Coal: An Experimental Study

2015 ◽  
Vol 60 (4) ◽  
pp. 1013-1028 ◽  
Author(s):  
Lei Zhang ◽  
Naj Aziz ◽  
Ting Ren ◽  
Jan Nemcik ◽  
Shihao Tu
Keyword(s):  
Coal Seam ◽  
Clean Energy ◽  
Gas Content ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Recovery ◽  
Nitrogen Injection ◽  
Gas Desorption ◽  
Effective Role ◽  
Study Laboratory

Abstract Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.

Impact of in-seam drilling performance on coal seam gas production and remaining gas distribution

2019 ◽  
Vol 59 (1) ◽  
pp. 328
Author(s):  
Fengde Zhou ◽  
Glen Fernandes ◽  
Joao Luft ◽  
Kai Ma ◽  
Mahmoud Oraby ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Gas Content ◽  
Gas Distribution ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Saturation ◽  
Drilling Performance ◽  
Permeability Anisotropy ◽  
The Impact

Drilling horizontal wells in low permeability coal seams is a key technology to increase the drainage area of a well, and hence, decrease costs. It’s unavoidable that some parts of the horizontal section will be drilled outside the targeted coal seam due to unforeseen subsurface conditions, such as sub-seismic faulting, seam rolls, basic geosteering tools, drilling practices and limited experiences. Therefore, understanding the impact of horizontal in-seam drilling performance on coal seam gas (CSG) production and remaining gas distribution is an important consideration in drilling and field development plans. This study presents a new workflow to investigate the impact of horizontal in-seam performance on CSG production and gas distribution for coal seams with different porosity, permeability, permeability anisotropy, initial gas content (GC), initial gas saturation and the ratio of in-coal length to in-seam length (RIIL). First, a box model with an area of 2 km × 0.3 km × 6 m was used for conceptual simulations. Reduction indexes of the cumulative gas production at the end of 10 years of simulations were compared. Then, a current Chevron well consisting of a vertical well and two lateral wells, was selected as a case study in which the impact of outside coal drilling on history matching and remaining gas distribution were analysed. Results show that the RIIL plays an increasing role for cases with decreasing permeability or initial gas saturation, while it plays a very similar role for cases with varied porosity, permeability anisotropy and GC. The size and location of outside coal drilling will affect the CSG production and remaining gas distribution.

COAL SEAM GAS IN THE SOUTHERN SYDNEY BASIN, NEW SOUTH WALES

1997 ◽  
Vol 37 (1) ◽  
pp. 415 ◽  
Author(s):  
M.M. Faiz ◽  
A.C. Hutton
Keyword(s):  
Coal Seam ◽  
New South ◽  
Geological Structure ◽  
Gas Content ◽  
Gas Composition ◽  
Late Permian ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
South Wales ◽  
Coal Measures

The coal seam gas content of the Late Permian Illawarra Coal Measures ranges from Methane that occurs within the basin was mainly derived as a by-product of coalification. Most of the CO2 was derived from intermittent magmatic activity between the Triassic and the Tertiary. This gas has subsequently migrated, mainly in solution, towards structural highs and accumulated in anticlines and near sealed faults.The total desorbable gas content of the coal seams is mainly related to depth, gas composition and geological structure. At depths

scholarly journals Advanced Computational Methods for Mitigating Shock and Vibration Hazards in Deep Mines Gas Outburst Prediction Using SVM Optimized by Grey Relational Analysis and APSO Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiang Wu ◽  
Zhen Yang ◽  
Dongdong Wu
Keyword(s):  
Coal Seam ◽  
Grey Relational Analysis ◽  
Gas Content ◽  
Gas Release ◽  
Coal Seam Gas ◽  
Relational Analysis ◽  
Gas Outburst ◽  
Gas Desorption ◽  
Svm Model ◽  
Grey Relational

Gas outburst poses a huge threat to the safe production of coal mines. Therefore, the prediction of gas outburst has always been a hot topic for researchers. In recent years, the use of artificial intelligence algorithms for gas outburst prediction has made progress, such as using BP neural network, GA algorithm, and SVM algorithm. Despite these progresses, predicting the gas outburst more accurately and efficiently still remains a great challenge. In this work, an algorithm based on grey relational analysis and SVM using adaptive particle swarm optimization (APSO-SVM) for gas outburst prediction is proposed. Grey relational analysis was used to extract the four most relevant ones from nine gas outburst prediction parameters (geological structure zone distance, coal seam gas content, gas release initial velocity, gas desorption index-K1, drill cuttings volume, coal seam depth, coal seam thickness, coal destruction type, and coal firmness coefficient) to give the needed parameters for SVM model. Higher prediction accuracy was then obtained with the selected parameters composed by coal seam gas content, gas release initial velocity, gas desorption index-K1, and drill cuttings volume. Moreover, adaptive particle swarm optimization (APSO) was used to optimize the penalty factor and kernel parameters of the support vector machine to improve the global search ability and avoid the occurrence of the local optimal solutions. The APSO-SVM model was applied to the prediction of gas outburst in 31004 tunneling face of Xinyuan Coal Mine, Yangquan City, Shanxi Province, China. We further introduced the criteria of accuracy, precision, recall, and F 2 -score to evaluate the prediction results of different models. The results show that, in the gas outburst prediction, the accuracy of the APSO-SVM model is 98.38%, the precision and recall are both 100%, and F 2 -score is 1. Comparative studies confirm that APSO-SVM displayed better performance than SVM and PSO-SVM models for the applied grey relational analysis assisted gas outburst prediction. These obtained results indicate the validity of APSO-SVM model for gas outburst prediction.

The Application of Crossing and Grid Drainage Boreholes in Floor Tunnel for Coal Roadway Safety Tunneling

2014 ◽  
Vol 962-965 ◽  
pp. 1169-1174
Author(s):  
Hong Qing Zhu ◽  
Bei Fang Gu ◽  
Min Bo Zhang ◽  
Chao Yu ◽  
Zhen Zhang
Keyword(s):  
Coal Seam ◽  
Gas Pressure ◽  
Gas Content ◽  
Dynamic Phenomenon ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Technical Parameters ◽  
Coal Roadway ◽  
Roadway Safety ◽  
The Relationship

In order to reduce the danger of single coal seams outburst during the tunneling in coal roadway and ensure the tunneling of coal seams, this text analyzed the mechanism of crossing drilling against outburst; studied the area measures of floor tunnel crossing and grid drainage boreholes in coal roadway, Designed and optimized the drilling technical parameters; Analyzed the relationship between the drainage concentration and scalar; Calculated the maximum overlying coal seam gas to spare scalar quantity is 224300 m3 ;Used a variety of indicators to investigate the effect of outburst prevention. It shows that Gas content and gas pressure have significant lower than drainage. After the drainage up to standard, all the sensitive indexes is not overrun, during the coal roadway tunneling, it does not appears dynamic phenomenon. Solve the problem of mining imbalances, guaranteed the safety driving of roadway.

scholarly journals Calculation Model and Rapid Estimation Method for Coal Seam Gas Content

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 223 ◽  
Author(s):  
Fakai Wang ◽  
Xusheng Zhao ◽  
Yunpei Liang ◽  
Xuelong Li ◽  
Yulong Chen
Keyword(s):  
Coal Seam ◽  
Coal Sample ◽  
Calculation Model ◽  
New Method ◽  
Gas Content ◽  
Coal Seam Gas ◽  
Rapid Estimation ◽  
Coalbed Gas ◽  
Gas Desorption ◽  
Study Results

Coalbed gas content is the most important parameter for forecasting and preventing the occurrence of coal and gas outburst. However, existing methods have difficulty obtaining the coalbed gas content accurately. In this study, a numerical calculation model for the rapid estimation of coal seam gas content was established based on the characteristic values of gas desorption at specific exposure times. Combined with technical verification, a new method which avoids the calculation of gas loss for the rapid estimation of gas content in the coal seam was investigated. Study results show that the balanced adsorption gas pressure and coal gas desorption characteristic coefficient (Kt) satisfy the exponential equation, and the gas content and Kt are linear equations. The correlation coefficient of the fitting equation gradually decreases as the exposure time of the coal sample increases. Using the new method to measure and calculate the gas content of coal samples at two different working faces of the Lubanshan North mine (LBS), the deviation of the calculated coal sample gas content ranged from 0.32% to 8.84%, with an average of only 4.49%. Therefore, the new method meets the needs of field engineering technology.

scholarly journals Study on Reservoir Properties and Critical Depth in Deep Coal Seams in Qinshui Basin, China

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Guiqiang Zheng ◽  
Bin Sun ◽  
Dawei Lv ◽  
Zhejun Pan ◽  
Huiqing Lian
Keyword(s):  
Coal Seam ◽  
Step Change ◽  
Gas Content ◽  
Burial Depth ◽  
Critical Depth ◽  
Coal Seams ◽  
Reservoir Properties ◽  
Qinshui Basin ◽  
Geological Conditions ◽  
Change Characteristics

Coalbed methane (CBM) reservoir properties and relationship of properties with burial depth were studied based on the data derived from 204 deep CBM production wells in Qinshui Basin, China. Through the study, it is found that permeability and porosity decrease with the increase of burial depth and the decreasing trend shows step-change characteristics at a critical burial depth. They also show divisional characteristics at certain burial depth. Gas content, geostress, and geotemperature increase with the increase of burial depth, and the increasing trend shows step-change characteristics and also have divisional characteristics at certain burial depth. Based on the previous study on the reservoir property changes with burial depth, three series of critical depth using different parameters are obtained through simulating the critical depth using the BP neural network method. It is found that the critical depth is different when using different parameters. Combined the previous study with the normalization of three different parameter types, the critical depth in Qinshui Basin was defined as shallow coal seam is lower than 650 m and transition band is 650–1000 m, while deep coal seam is deeper than 1000 m. In deep coal seams, the geological conditions and recovery becomes poor, so it can be defined as unfavorable zones. Therefore, other development means, for example, CO2 injection, need to be used to accelerate the deep coal methane development.

Quantifying the impact of capillary trapping on coal seam gas recovery

2020 ◽  
Vol 83 ◽  
pp. 103588
Author(s):  
Yiran Zhu ◽  
Huilin Xing ◽  
Victor Rudolph ◽  
Zhongwei Chen
Keyword(s):  
Coal Seam ◽  
Coal Seam Gas ◽  
Gas Recovery ◽  
Capillary Trapping ◽  
The Impact

Quantitative Evaluation of Coal Seam Gas Content Estimate Accuracy

1995 ◽  
Author(s):  
Matthew J. Mavor ◽  
Timothy J. Pratt ◽  
Charles R. Nelson
Keyword(s):  
Coal Seam ◽  
Quantitative Evaluation ◽  
Gas Content ◽  
Coal Seam Gas

COAL SEAM GAS—PETROLEUM OR MINERAL

1997 ◽  
Vol 37 (1) ◽  
pp. 589
Author(s):  
D.J. Gately
Keyword(s):  
Private Sector ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Resource Development ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Commercial Use ◽  
Private Sector Investment ◽  
History Of ◽  
Policy Shift

1996 was a watershed year for gas exploration in Queensland: the increasing private sector investment in the search for and commercial use of methane gas from coal seams received legislative endorsement. Coal seam gas (CSG), also known as coalbed methane or CBM, was officially designated as petroleum, with exploration for and production of CSG to be administered under the Petroleum Act.The paper traces the history of exploration for CSG in Queensland since 1976, culminating in a policy shift in 1996. In Queensland there is now potential for overlapping titles and competitive resource development.

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