Analysis of Coalbed Methane (CBM) Enrichment and Main Controlling Factors in Southern Junggar Basin

2013 ◽  
Vol 848 ◽  
pp. 251-254
Author(s):  
Xiang Hao Wang ◽  
Yan Bin Wang ◽  
Jing Jing Fan ◽  
Jin Wang ◽  
Cheng Long Liu

Using data analysis and comparative analysis, the distribution of Coalbed methane (CBM) gas content in southern Junggar were analyzed on the basis of the southern Junggar Basin coalfield geological data, and the main controlling factors of CBM accumulation were studied. The results show that, Gas content ranges from 2cm3/g to 15cm3/g, which overall is highest in central and eastern and becomes progressively smaller in trend of westward. The study area has many characteristics, such as Multi-seam, large coal seam thickness, mainly Fine-grained clastic rock, which is conducive to the enrichment of the CBM. Study area belongs to confined aquifer of low water-richness and receives the supply of atmospheric precipitation and river. In the coal seams within a certain depth formed Runoff water and the CBM diffusion pattern of desorption - diffusion - transport - water soluble gas runoff, which are not conducive to the enrichment of the CBM.

2018 ◽  
Vol 37 (1) ◽  
pp. 429-452
Author(s):  
Wenchao Shen ◽  
Longyi Shao ◽  
Wenguang Tian ◽  
Gang Chen ◽  
Fei Chen ◽  
...  

The Wuwei Basin is located in the Gansu Corridor, which has abundant coalbed methane resources of 2.75 × 1011 m3. However, a low degree of coalbed methane exploration exists, and only a few wells have been drilled in local regions due to insufficient understanding of coalbed methane enrichment and its main controlling factors. This study analyzed the controlling factors of coalbed methane enrichment, including coal reservoir characteristics, hydrogeological conditions, and the original sedimentary environment of the coal-bearing strata. The results showed that the main coal seams were developed in the Taiyuan Formation, and were mostly concentrated in the Yingpan Sag in the south and the Ermahu Sag in the north of the study area. The macrolithotype of the coals in this basin was mainly semi-bright coal with a medium to high rank. Coal macerals were mainly vitrinite, ranging between 65.1% and 91.6% (averaged 81.70%), followed by liptinite, ranging between 1.9% and 29.5% (averaged 8.82%), and inertinite, ranging between 0.2% and 16.5% (averaged 3.66%). Mineral contents varied from 2.5% to 15.1% (averaged 6.16%). The macrolithotype and microlithotype of the Taiyuan Formation coals were favorable for coalbed methane formation. Through comparative analysis of moisture content, ash yield, gas content, and coal-forming sedimentary environments, it was found that the coal formed in the lagoon environment had a higher gas content and lower ash yield than that of the coal formed in the tidal flat environment. The high contents of total dissolved solids in aquifers around coal seams (1.75–16.70 g/L) reflected the closed hydrodynamic environment and were favorable for the preservation of coalbed methane in the Yingpan Sag. Considering various controlling factors (i.e., structure, sedimentation and hydrogeology), three coalbed methane enrichment models were proposed. The model of coalbed methane enrichment in the synclinorium was the most favorable for the enrichment of coalbed methane in the Yingpan Sag.


2020 ◽  
Author(s):  
aobo zhang ◽  
shuling Tang

<p>In order to investigate the controlling of the sedimentation environment evolution on the coalbed methane system in Xishanyao Formation on the southern margin of Junggar Basin,using drilling wells,logging wells,outcrops and other data with the assistance of fine analysis methods,such as scanning electron microscope and image granularity,the coalbed methane system was divided,and its sedimentation evolution process was researched. The research results show that sand body of five types of sedimentation microfacies,whose water and air blocking capacity is sorted as “diversion channel<crevasse splay and beach dam<natural levee and shore-shallow lake”,can be identified in the research area,and single-well vertical coalbed methane system was divided; during the SQ1—SQ2 period,the rise of lake level led to the expansion of the development area of lacustrine facies,as well as the weakening of the coal-accumulating process which was mainly concentrated in the TST and LST stages of SQ1,and the east-west characteristic difference regarding the coalbed development and gas content appeared and was in accordance with the plane distribution of sedimentary facies; during exploitation,the coalbed methane system should be defined according to the blocking capability of surrounding rock,appropriate exploitation methods should be selected according to the characteristics of each system,and the avoidance of vertically joint-developing sandstone aquifer and combined layer series of development should be paid attention to.</p>


Author(s):  
Yinqing Zuo ◽  
Qianhua Xiao ◽  
Zhiyuan Wang ◽  
Xiuqin Lu ◽  
Yang Song ◽  
...  

2013 ◽  
Vol 634-638 ◽  
pp. 3645-3649
Author(s):  
Lin Chao Dai ◽  
Guang Cai Wen ◽  
Zhen Liu ◽  
Hui Ming Yang ◽  
Bo Wang

In order to determine coal seam gas content accurately, the single factor method was adopted to study geological factors that affect coal seam gas content of a coal mine. Bedrock depth, 50m influence coefficient and coal thickness are identified as the main controlling factors of gas content. And the corresponding correlation coefficient are: 0.6011, 0.3899, 0.2527. Factors such as effective trapping thickness, moisture content and ash content are regarded as secondary factors. Then the SVM theory was used to set up a nonlinear prediction model between coal seam gas content and main controlling factors, and the gas content was predicted. Results show that single factor method can be used to determine main controlling factors of coal seam gas and the gas content SVM model can predict gas content accurately. Besides, the research findings can provide technical basis for gas drainage and gas outburst prevention.


Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1867 ◽  
Author(s):  
Xu Ge ◽  
Dameng Liu ◽  
Yidong Cai ◽  
Yingjin Wang

To study the gas potential of coalbed methane (CBM) in the Fukang area, southern Junggar Basin (SJB) of North China, different methods including multiple geophysical logging, the Kim method with proximate analysis data, and Langmuir adsorption were used to evaluate the gas content. Furthermore, the geological controls on gas content were evaluated. One hundred sixteen CBM wells with geophysical logging and 20 with field-measured gas content were adopted to assess the gas content in the Fukang area of SJB, NW China. The results show that the two geophysical logging variables (DEN and CNL) were favorable for evaluating the gas content due to the perfect correlation with the measured gas content. The gas content varies from 4.22 m3/t to 16.26 m3/t, and generally increases with increasing burial depth. The gas content in coal seams along the synclinal axis is significantly higher than that along the synclinal wing in the west zone. In the east zone, the gas content of the westward is higher than that of the eastward because of the fault coating effect by reverse fault. Generally, the gas content of the SJB is in the order of syncline > surrounding reverse fault > slope of syncline > slope of anticline > central of reverse fault, if only geological structure features are considered. The favorable areas for CBM concentration appear to be a composite gas controlling result of multiple geological factors. Two typical geological scenarios with low gas content and high gas content were revealed. In the Fukang area of SJB, the low gas content is mainly due to the normal fault and roof lithology of sandstone. The most favorable area of high gas content for CBM exploration and development is in the northeast, where reversed fault, synclinal axis, mudstone roof lithology, and burial depth coincide with high gas content.


2013 ◽  
Vol 868 ◽  
pp. 696-699 ◽  
Author(s):  
Cheng Long Liu ◽  
Xiang Hao Wang ◽  
Kun Liu ◽  
Jin Wang ◽  
Hui Guo ◽  
...  

Junggar Basin is located in north Xinjiang and it has a huge amount of coalbed methane resources with less exploration and mining. The most vital characteristic in junggar basin is coal dip angel and gas content varies a lot in different areas. This paper reveals the relationship between gas content and coal seam dip angel, bigger the coal seam dip angel lower the gas content. The target area of CBM exploration and mining in junggar basin is HEGSH-STH area, HEGSHX area, BSMY-JJM area,LJM area, KLMY area, HSTLG area and XZJQ area. Gas content is mainly influenced by tectonic movement in junggar basin, it is low in complex structure area and high in simple structure area. Inclination of the coal seam stands for the complexity of the structure in junggar basin, the structure is complex when the coal seam is steep, it is simple when the coal seam is flat. The result can be used as a new method for coalbed methane exploration and development in inclined coal seam areas, small coal dip area should be chosen as the high gas content target.


2015 ◽  
Vol 89 (s1) ◽  
pp. 182-183 ◽  
Author(s):  
Haijuan BAO ◽  
Wenjun HE ◽  
Liying FEI ◽  
Xiyu JIA ◽  
Menglin ZHENG ◽  
...  

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