The application study of complex analysis in detection of shear wave splitting due to vertical fractures;

The purpose of this research is to investigate the properties of pore-fracture system and to reveal the relationship between the physical properties of coal reservoirs and recovery of coalbed methane in Huainan and Huaibei coal-fields.

There exist lots of factors influencing the differencial distribution of permeability,from such aspects as the development of fracture system,the effective stress of coal-bed reservoirs,coal-bed tectonic evolution and coal-bearing rock metamorphic degree,the relationship among them and spacial distribution of highly permeable areas and the research progress are illustrated.

Based on the theoretical analysis and testing studies,the relationship between the fracture coefficients of surrounding rocks and the peripheral displacements of the laneway is set up.

In this paper, the advances in overseas research on the origin and reservoir characteristics of coalbed gas (CBG) are selectively summarized in the light of three aspects: the CBG-generating mechanism and its geological controls; the porous structure and adsorption/desorption of coal; fissure systems and their effect on the permeability of coal reservoirs.

With the analysis on the pressurized mercury experiments, a research was done on the development conditions of the porosity and fissure systems in the seams of the coalfield in Qinan Mining Area.

The coupling analysis between permeability and stress included permeability-stress coupling of porous media and permeability-stress coupling of fissure system.

Based on the analysis of nonlinear dynamics to time series of strain and stress which are tested by MTS to lots of joint systems of sandstone specimens,a new rule to find the largest Lyapunov exponent is established by introducing LE1-m mathematical model and unit-step function.