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Response of Macromolecular Structure to Deformation in Tectonically Deformed Coal 被引量:8
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作者 LI Xiaoshi JU Yiwen +1 位作者 HOU Quanlin FAN Junjia 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第1期82-90,共9页
The structural evolution of tectonically deformed coals (TDC) with different deformational mechanisms and different deformational intensities are investigated in depth through X-ray diffraction (XRD) analysis on 3... The structural evolution of tectonically deformed coals (TDC) with different deformational mechanisms and different deformational intensities are investigated in depth through X-ray diffraction (XRD) analysis on 31 samples of different metamorphic grades (R : 0.7%-3.1%) collected from the Huaibei coalfield. The results indicated that there are different evolution characteristics between the ductile and brittle deformational coals with increasing of metamorphism and deformation. On the one hand, with the increase of metamorphism, the atomic plane spacing (d002) is decreasing at step velocity, the stacking of the BSU layer (Lc) is increasing at first and then decreasing, but the extension of the BSU layer (La) and the ratio of La/Lc are decreasing initially and then increasing. On the other hand, for the brittle deformational coal, d002 is increasing initially and then decreasing, which causes an inversion of the variation of Lc and La under the lower-middle or higher-middle metamorphism grade when the deformational intensity was increasing. In contrast, in the ductile deformational coals, d002 decreased initially and then increased, and the value of L~ decreased with the increase of deformational intensity. But the value of La increased under the lower-middle metamorphism grade and increased at first and then decreased under the higher-middle metamorphism grade. We conclude that the degradation and polycondensation of TDC macromolecular structure can be obviously impacted during the ductile deformational process, because the increase and accumulation of unit dislocation perhaps transforms the stress into strain energy. Meanwhile, the brittle deformation can transform the stress into frictional heat energy, and promote the metamorphism and degradation as well. It can be concluded that deformation is more important than metamorphism to the differential evolution of the ductile and brittle deformational coals. 展开更多
关键词 tectonically deformed coal X-ray diffraction deformational mechanism deformationalintensity macromolecular structure
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Spectra response from macromolecular structure evolution of tectonically deformed coal of different deformation mechanisms 被引量:19
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作者 LI XiaoShi JU YiWen +1 位作者 HOU QuanLin LIN Hong 《Science China Earth Sciences》 SCIE EI CAS 2012年第8期1269-1279,共11页
Coals with different deformation mechanisms(brittle deformation,brittle-ductile deformation,and ductile deformation) repre-sent different ways in macromolecular structure evolution based on the metamorphism.The evolut... Coals with different deformation mechanisms(brittle deformation,brittle-ductile deformation,and ductile deformation) repre-sent different ways in macromolecular structure evolution based on the metamorphism.The evolution of coal structure could affect the occurrence condition of coalbed methane(CBM) because the nanopore structure affected by macromolecular struc-ture is the most important reservoir for CBM.This paper analyzes the evolutions and mechanisms of structure and functional group of tectonically deformed coals(TDCs) collected from Huainan-Huaibei coalfield using X-ray diffraction(XRD),Raman spectroscopy,and Fourier Transform Infrared(FTIR) spectroscopy methods.The results show that the macromolecular struc-ture evolutions of TDC are different from the primary structure coal as a result of the different metamorphic grade and defor-mation mechanisms.The different deformation mechanisms variously affect the process of functional group and polyconden-sation of macromolecular structure.Furthermore,the tectonic deformation leads to secondary structural defects and reduces the structure stability of TDC.The coupled evolution on stacking and extension caused by the changes of secondary structural de-fects results from different deformation mechanisms.We consider that the changes of chemical structure and secondary struc-tural defects are the primary reasons for the various structure evolutions of TDC compared with primary structure coal. 展开更多
关键词 tectonicaHy deformed coal METAMORPHISM deformation mechanism macromolecular structure secondary structuraldefect
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Micro-structural evolution and their effects on physical properties in different types of tectonically deformed coals 被引量:45
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作者 Yiwen Ju Kray Luxbacher +4 位作者 Xiaoshi Li Guochang Wang Zhifeng Yan Mingming Wei Liye Yu 《International Journal of Coal Science & Technology》 EI CAS 2014年第3期364-375,共12页
The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact p... The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact physical properties such as porosity and permeability.This study focuses on structure and properties of TDC from the Huaibei and Huainan coal mining areas of southern North China.Relationships between the macromolecular structure and the pore structure of TDC were analyzed using techniques such as X-ray diffraction,high-resolution transmission electron microcopy,and the low-temperature nitrogen adsorption.The results indicated that the directional stress condition can cause the arrangement of basic structural units(BSU)more serious and closer.And,the orientation is stronger in ductile deformed coal than in brittle deformed coal.Tectonic deformation directly influences the macromolecular structure of coal and consequently results in dynamic metamorphism.Because the size of BSU in brittle deformed coal increases more slowly than in ductile deformed coal,frictional heating and stress-chemistry of shearing areas might play a more important role,locally altering coal structure under stress,in brittle deformed coal.Strain energy is more significant in increasing the ductile deformation of coal.Furthermore,mesopores account for larger percentage of the nano-scale pore volume in brittle deformed coals,while mesopores volume in ductile deformed coal diminishes rapidly along with an increase in the proportion of micropores and sub-micropores.This research also approved that the deformations of macromolecular structures change nano-scale pore structures,which are very important for gas adsorption and pervasion space for gas.Therefore,the exploration and development potential of coal bed methane is promising for reservoirs that are subjected to a certain degree of brittle deformation(such as schistose structure coal,mortar structure coal and cataclastic structure coal).It also holds promise for TDC resulting from wrinkle structure coal of low ductile deformation and later superimposed by brittle deformation.Other kinds of TDC suffering from strong brittle-ductile and ductile deformation,such as scale structure coal and mylonitic structure coal,are difficult problems to resolve. 展开更多
关键词 Tectonically deformed coals Formation mechanisms macromolecular structure Pore structure Micro-structured evolution Coal bed methane
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