TITLE:
Excess Coalbed Methane Production Mechanism in the Process of Coal Tectonic Deformation
AUTHORS:
Yi Luo, Shuying Li
KEYWORDS:
Tectonic Coal, Gas Generation by Deformation, Mechanism of Gas Generation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.4 No.7,
July
30,
2016
ABSTRACT: Source and occurrence of Excess Coalbed Methane is a long-term concern
research topic in Coal Geology and Structural Geology. Since it is essential to
understand the outburst mechanism of coal gas, and to support the coalbed
methane development projects as the theoretical basis. We found in the study
that, huge imparity is behind the evolutionary trend on molecular structure and
the mechanism of influence from different deformation. The thesis demonstrates
its probable routes of gas evolution according to distinct deformation
mechanisms of coal. In the role of brittle deformation mechanism, a rapidly
formed advantage rupture surface along with sliding motion from which has
worked on coal. As another result, mechanical energy has transformed into
friction and kinetic energy during the process. Kinetic energy increases
simultaneously, which brings some results, that the new generated gas molecule.
While the chemical structure of coal remains in a steady-state and do not react
easily an outburst with gas. Mechanical energy turns into strain energy through
its ductile deformation mechanism. The dislocation or lamellar slip made
disordered between the constitutional units of aromatic rings and aromatic
lamellas, as soon as secondary structural defects created. On another hand,
molecular motion accelerates and splits off the small molecular on the side
chain, due to the dissociation of aromatic nucleus; CH4 gas molecular was generated and placed
in the secondary structural defect of coal, along with a great deal of strain
energy in non-steady-state. By breaking away the balance maintaining terms,
huge strain energy releases suddenly, small moleculars are free from the
secondary structure defect, react outburst with gas. Furthermore to extend the
discussion of the conventional physical ideas on coal absorb gas, according to
the phenomenon of exceeded CBM, the gas molecular has a significant chance existing
in a low bond energy of chemical bonds of coal structure.