scholarly journals The Relationship between Mining-Induced Stress and Coal Gas under an Optimized Support Scheme: A Case Study in the Guanyinshan Coal Mine, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tianjun Zhang ◽  
Jiaokun Wu ◽  
Yong Chen ◽  
Hong Ding ◽  
Hongyu Ma ◽  
...  
Keyword(s):  
Gas Pressure ◽  
Gas Content ◽  
Rock Support ◽  
Drill Cuttings ◽  
Coal Gas ◽  
Gas Desorption ◽  
Induced Stress ◽  
Coal And Gas Outbursts ◽  
Residual Gas ◽  
The Relationship

Stress is one of the main factors influencing coal and gas outbursts. The apparent effects of the crustal stress, the structural stress, and the mining-induced stress increase as the depth of mining increases. At present, there have been few studies of the relationship between the comprehensive analyses of the crustal stress, mining-induced stress, and coal gas. The in situ measurement of the relationship between stress-related behaviors and coal gas under the influence of mining was conducted through experimental analysis of surrounding rock support and coal and gas outburst control and optimization of surrounding rock support materials and system construction. The results showed that the mining-induced stress first increased to a peak value, then gradually decreased, and tended to stabilize as the footage progresses. Stress appears at 96 m ahead due to mining; after 57 m of advancing, there is a large increase until it passes through this area. The stress in front of the working face increases linearly, and the increase range is obviously larger than that of the coal body in a certain range on both sides. The support anchoring force gradually decreased and tended to be stable after rapidly increasing to a maximum value. The deep displacement of the roof increased linearly and tended to be stable after reaching an accumulated displacement which can reach 16-28 mm. The residual gas pressure in front of mining operations decreased rapidly, and beyond 15 m on each side of the roadway, it decreased significantly. The residual gas pressure and gas content were consistent with the gas desorption index of drill cuttings due to the influences of gas predrainage and mining. The stress along the direction of the roadway and the residual gas content, the residual gas pressure, and the gas desorption index of drill cuttings conform to the logarithmic functional relationship. The research results provide a basis for the comprehensive prevention and control of coal and gas outbursts from multiple angles considering stress, coal, and gas.

The Effect Evaluation of Removing Outburst through Bedding and Layer-through Boreholes Combined Gas Drainage

2012 ◽  
Vol 256-259 ◽  
pp. 366-371
Author(s):  
Zhong Ming Zhao ◽  
Lei Wang ◽  
Jian Bang Wu
Keyword(s):  
Gas Pressure ◽  
Gas Content ◽  
Effect Evaluation ◽  
Prevention Measures ◽  
Gas Drainage ◽  
Residual Gas ◽  
Favorable Conditions

In order to test the validity of regional outburst prevention measures that combined the bedding boreholes and layer-through boreholes in 3104 coalface, according to the relevant provisions, used drilling index, pre-pumping index and gas index to evaluate the effect of removing outburst in 3104 coalface. The evaluation results shown that through the pre-pumping gas, the rate of pre-pumping gas was 53.7%, more than 30%; residual gas content was 2.85～5.07m3/t, less than 8m3/t; residual gas pressure was 0.01～0.02MPa, less than 0.74 MPa. Therefore, the coalface has eliminated the danger of outburst and created favorable conditions for safety mining.

STUDY OF RESIDUAL GAS CONTENT OF COAL SEAMS IN ERUNAKOVSKY DEPOSIT OF KUZBASS

2020 ◽  
pp. 5-11
Author(s):  
Sergej N. Shirjaev ◽  
Oleg V. Tailakov ◽  
Denis N. Zastrelov ◽  
Artem V. Gerasimov
Keyword(s):  
Gas Content ◽  
Coal Seams ◽  
Residual Gas

A New Regression-Based Method for Accurate Measurement of Coal and Shale Gas Content

2010 ◽  
Vol 13 (02) ◽  
pp. 359-364 ◽  
Author(s):  
E.. Shtepani ◽  
L.A.. A. Noll ◽  
L.W.. W. Elrod ◽  
P.M.. M. Jacobs
Keyword(s):  
Adsorption Isotherm ◽  
Storage Capacity ◽  
Recovery Process ◽  
Proximate Analysis ◽  
Core Sample ◽  
Gas Content ◽  
Accurate Estimation ◽  
Atmospheric Conditions ◽  
Curve Fit ◽  
Residual Gas

Summary Gas content and storage capacity are the key parameters for determination of the gas resources and reserves in unconventional reservoirs. These parameters must be obtained from laboratory experiments in core samples such as desorption canister tests and adsorption isotherm experiments. Desorption canister testing is performed to determine the total adsorbed gas content, gas composition, and the total desorption time. Adsorption isotherm experiments are conducted to determine the gas storage capacity with pressure and for CO2 sequestration purposes. Other analyses of coals include proximate analysis and bulk-density measurements of all samples. Shales are commonly analyzed for total organic carbon in lieu of proximate analysis. The gas content is estimated by placing selected freshly cut reservoir samples in airtight sealed canisters and measuring desorbed gas volume as a function of time at atmospheric conditions. Total gas content is the summation of three components: "lost gas," desorbed gas, and "residual gas." "Lost gas" is the volume of the gas that desorbs from the sample during the recovery process at the wellsite, before the core sample can be sealed in a desorption canister. "Residual gas" is the gas that remains sorbed on the sample at the completion of the canister desorption test. A disadvantage of this procedure is the estimation of "lost gas." The volume of the "lost gas" is usually estimated by extrapolation of desorbed data to time zero using linear and/or polynomial curve-fit to the plot of cumulative desorbed gas vs. square root of time. The differences between both methods can become more pronounced, especially in high-gas-content reservoirs. In this paper a new method, which is based on nonlinear regression of measured gas content, is presented. This technique offers an accurate estimation of lost gas, which, coupled with sorption isotherm, has an impact on the calculation of gas in place, the recoverable reserves, and production profiles.

Development and Verification of Measurement Equipment for Residual Gas Content of a Coal Sample

2016 ◽  
Author(s):  
Hyeongjun Seo ◽  
Sunil Kwon ◽  
Seungrok Lee
Keyword(s):  
Coalbed Methane ◽  
Coal Sample ◽  
Gas Content ◽  
Measurement Equipment ◽  
Test Results ◽  
Excellent Performance ◽  
Material Type ◽  
Residual Gas

This paper presents the development of measurement equipment for residual gas content consisting of a cylindrical canister, a grooved rod, and a crusher, as well as a test for verifying its efficiency and crushing ratio. The equipment was designed by considering factors such as crushing mode, material type and size, sealing, empty volume inside the canister, and portability to site. Particularly by designing a rod having grooves, unlike existing rod mills, the initial crushing time was shortened. Test results showed that an average of 83 min was consumed to achieve a 96% crushing ratio, which proved the developed equipment had excellent performance for use at coalbed methane sites.

scholarly journals Prediction of Residual Gas Content during Coal Roadway Tunneling Based on Drilling Cuttings Indices and BA-ELM Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Zhenhua Yang ◽  
Hongwei Zhang ◽  
Sheng Li ◽  
Chaojun Fan
Keyword(s):  
Coal Seam ◽  
Extreme Learning Machine ◽  
Back Propagation ◽  
Prediction Method ◽  
Gas Content ◽  
Percentage Error ◽  
Support Vector ◽  
Prevention Measures ◽  
Residual Gas ◽  
Learning Machine

In order to predict the residual gas content in coal seam in front of roadway advancing face accurately and rapidly, an improved prediction method based on both drilling cuttings indices and bat algorithm optimizing extreme learning machine (BA-ELM) was proposed. The test indices of outburst prevention measures (drilling cuttings indices, residual gas content in coal seam) during roadway advancing in Yuecheng coal mine were first analyzed. Then, the correlation between drilling cuttings indices and residual gas content was established, as well as the neural network prediction model based on BA-ELM. Finally, the prediction result of the proposed method was compared with that of back-propagation (BP), support vector machine (SVM), and extreme learning machine (ELM) to verify the accuracy. The results show that the average absolute error, the average absolute percentage error, and the determination coefficient of the proposed prediction method of residual gas content in coal seam are 0.069, 0.012, and 0.981, respectively. This method has higher accuracy than other methods and can effectively reveal the nonlinear relationship between drilling cuttings indices and residual gas content. It has prospective application in the prediction of residual gas content in coal seam.

Analysis of the Natural Methane Content of Boldyrevsky Seam at S.M. Kirov Mine of JSC SUEK-Kuzbass

2021 ◽  
pp. 61-66
Author(s):  
E.V. Fedorov ◽  
◽  
S.B. Kulibaba ◽  
A.A. Meshkov ◽  
◽  
...  
Keyword(s):  
Methane Content ◽  
Actual Data ◽  
Gas Content ◽  
Coal Seams ◽  
Actual Distribution ◽  
Coal Gas ◽  
Residual Gas ◽  
Mine Workings ◽  
Host Rocks

S.M. Kirov mine of JSC SUEK-Kuzbass develops Boldyrevsky and Polenovsky seams and is classified as a super-category for methane. Under these conditions, the development of seams requires a set of measures for their degassing. Methods and parameters for degassing the main sources of methane release in the coal mines are selected considering the faces gas content. It is calculated based on the natural methane content of the coal seams and host rocks determined at the stage of geologic exploration activity. The aim of the work conducted by the authors is to establish the actual distribution of natural methane seam Boldyrevsky based on the analysis of research results of the coal-gas samples and experimental evaluation of the residual gas content in the mine workings. Natural gas content of the mine field of S.M. Kirov JSC SUEK-Kuzbass mine was determined based on the analysis of 538 coal-gas samples on 30 seams. All the coal and gas samples taken from Boldyrevsky seam were analyzed. Distribution of the actual values of natural methane content from the hypsometric depths of the seam was plotted. Distribution was plotted concerning the actual values of natural methane from hypsometric depths of the formation. The obtained data were compared with the results of experimental determination of the residual gas content of Boldyrevsky seam from the mine workings. Based on the results obtained, CH4 isogases were constructed based on the actual and maximum values of the natural methane content in Boldyrevsky seam. It is established that the natural methane content of Boldyrevsky seam, that was determined at the stage of geological exploration for the entire field of S.V. Kirov mine, has overestimated values — by 35–40 % compared to the actual data, and by 25–30% in relation to the maximum actual data.

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