Analysis of the Physical Characteristics of Coal Reservoir in Hancheng Mining Area, Ordos Basin, China

2015 ◽  
Vol 737 ◽  
pp. 805-808
Author(s):  
Yan Hui Yang ◽  
Qi Lu Xu

<p>Coalbed methane (CBM) which is a kind of efficient and clean unconventional natural gas will be the alternative energy in the future. The studying degree of predecessor is low to the pore-fracture structures of coal reservoir in Hancheng Mining area, Ordos Basin, China. It has been researched with some tests and the results are as follows: micropore is more, specific surface area is larger, throat radius is lesser, permeability is low, but the pore - fracture is development, phenomenon of mineral filling pore - fracture is widespread, sorting features of throat radius is better. From the point of test results, physical property of coal reservoir in the study area is good,which is suitable for the exploration and development of coalbed methane resources.</p>

2020 ◽  
Vol 38 (5) ◽  
pp. 1664-1679
Author(s):  
Aoxiang Zhang ◽  
Daiyong Cao ◽  
Yingchun Wei ◽  
Thomas E Rufford

Coal fines produced during drainage of coalbed methane reservoirs can affect the permeability of the coal reservoir and damage production facilities such as downhole pumps, shafts, and valves. Thus, to clarify the mechanism of coal fines output is very important to high production of coalbed methane. The characteristics of coal fines can be used to identify the sources of the coal fines and to develop reasonable means of controlling coal fines output. In this study, different coal fines characteristics were investigated to reveal the output mechanism of coal fines. The coal fines samples were collected from 16 coalbed methane wells, which located in Eastern Ordos Basin of China. And the wells are in different drainage stages. The coal fines samples were analyzed by using transmission light microscopy, reflection polarized optical microscopy, laser particle size analysis, X-ray diffraction, and scanning electron microscopy with energy dispersive X. The results show that the concentration of coal fines is in the range of 3–8% (volume percent). The sizes of the coal fine particles tended to be below 200 µm. The main components of pulverized coal are vitrinite and inorganic minerals and the average content of inorganic minerals account for 50.56% and the standard deviation is 0.0685. The morphology analysis results show that the shape of coal fines is different in different parts of the coalbed methane wells. The coal fines concentration increases with the increase in the thickness of the deformed coal, and decreases with the increase in the burial depth. The concentration of coal fines becomes higher with the increase of casing pressure and coal fines concentration increases with the increase of the variation of bottom hole pressure.


2014 ◽  
Vol 915-916 ◽  
pp. 1108-1112
Author(s):  
Ling Li ◽  
Da Zhen Tang ◽  
Hao Xu ◽  
Yao Chen ◽  
Ting Xu Yu

This paper focused on the influences of different coal macrolithotypes on the coal reservoir properties, using a variety of testing methods studied the connection between macro-lithotype of coal and properties. When coal lithotypes changing from dull coal, bright coal, semibright coal to semidull coal, the adsorption pores change from enclosed types to open, adsorption capacities improved in turn, which is favorable to adsorption, desorption and diffusion of coalbed methane. Seepage pores of bright coal are the most developed, semidull coal and semibright coal less, dull coal the least. The permeability of coal has a positive correlation between microfissure density and large pore content. Different macrolithotype of the same coal seam changes with the permeability could be divided into three stages, including fractures decrease rapidly stage, fractures decrease slowly stage and fractures tend to be closed stage.


2014 ◽  
Vol 675-677 ◽  
pp. 1347-1350 ◽  
Author(s):  
Qi Lu Xu ◽  
Wen Hui Huang ◽  
Yan Hui Yang ◽  
Bei Liu

Coalbed methane (CBM) which is a kind of efficient and clean unconventional natural gas will be the alternative energy in the future. Deformed coal which is harmful to CBM development was studied with logging curve. The logging curve characteristics and template which can be used directly had been put forward and applied in Shizhuang Block, Qinshui basin, China: (1) Deformed coal has low resistivity, low bulk density, high interval transit time, expanding well diameter and increasing neutron porosity in logging curve. (2) 3 type coals (undeformed coal-transitional coal - deformed coal) are arranged from lower-left corner to top right corner in order in AC and LSD diagram. (3)The deformed coal proportion of No.15 coal is significantly higher and it maybe the main restricting development factor. (4) The northeast and southwest of Shizhuang block have more deformed coal.


2011 ◽  
Vol 29 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Shuli Ding ◽  
Jiangang Zhu ◽  
Baiping Zhen ◽  
Zhanyong Liu ◽  
Qinfu Liu

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 644 ◽  
Author(s):  
Xinlu Yan ◽  
Songhang Zhang ◽  
Shuheng Tang ◽  
Zhongcheng Li ◽  
Yongxiang Yi ◽  
...  

Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.


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