Comprehensive Response And Identification Model Of Tectonically Deformed Coal Based On The Geology And Geophysical Methods

The study area in this paper is Suxian Mining area featured with the significant structural characteristics,widely developed and more complete types of tectonically deformed coal?TDC?samples.Based on the systermly analysis of the deformation characteristics and evolution history of the study area,various TDCs of different deformation series were systermly collected.Through the systematic research of the deformation environments,macro and micro deformation structural characteristics of TDCs,the evolution and difference characteristics of pore structure and structural fractures in various TDCs from different deformation environments were in-depth analyzed combining with the mercury intrusion porosimetry?MIP?,N₂ adsorption and CT scanner measurements.Based on the systematically study of elastic characteristics of undeformed coal and various TDCs,the distribution range,change rule and the influencing factors of elastic and rock physics parameters of different TDCs are determined.The research results provide important theoretical and technical support for geophysical exploration of TDC.The main innovations or achievements are as follows:?1?Combining with the profound analysis of the formation mechanism of TDCs,the inner relationship between the deformation environment and formation evolution of TDC has been determined.Based on systermly analysis of the structural characteristics of TDCs,the TDCs collected from Suxian mining area can be divided into 7 types,including cataclastic coal,porphyroclastic coal and granulitic coal under brittle deformation environment,schistose coal and scaly coal from shear deformation environment,and wrinkle coal and mylonitic coal under plastic deformation environment.?2?Evolution and differences of pore structure and structural fractures of various TDCs were determined.The porosity of various TDCs show the characteristics of“Gradually increase,discrete enhancement”with the increased deformation extent.The differences of pore structure of various TDCs are mainly reflected in the change of pore volume of the meso-and macropores.The differences of nanoscale pore structure and pore shape of various TDCs have been systermly analyzed based on the N₂ adsorption measurements.Through the observation of macro,micro structure and the analysis results of CT scanner measurement of the fractures in various TDCs,the fractures development characteristics and the change rule of various TDCs from different deformation environments were determined.?3?Based on the systermly study of elastic parameters of undeformed coal and various TDCs,the change regulation of elastic parameters were determined.Under different deformation environments,the P-wave and S-wave velocity,the P-wave and S-wave velocity ratio?Vp/Vs?,Poisson's ratio of different TDCs gradually reduce with the increased deformation extent.The Vp/Vs and the Poisson's ratio are sensitive to the deformation type of TDCs.?4?The anisotropy of P-wave and S-wave velocity of various TDCs were systermly analyzed for the first time.The change rule of the anisotropy of P-wave and S-wave velocity of various TDCs has been determined.The results of the anisotropy of P-wave and S-wave velocity of various TDCs show that the velocity anisotropy values of coal samples from the brittle deformation environment gradually raise with the increased deformation extent.The velocity anisotropy values of TDCs from shear deformation environment exhibit significantly high.For the TDCs from the plastic deformation environment,the velocity anisotropy values are relatively high.Then the velocity anisotropy index has been proposed for the identification of fractures characteristics in various TDCs.?5?Based on the research of the development regulation and differences of pore structure and structural fractures of various TDCs,the distribution range and change rule of rock physics parameters of different types of TDCs have been further studied.The results display that the key factors influencing the rock physics parameters of different TDCs are as the preservation of the primary structure of coal,the porosity and pore shape of coal samples are the secondary factors.Combined with the the P-wave and S-wave velocity ratio?Vp/Vs?and wave impedance distribution range,the rock physics identification template of TDC has been established.?6?A case study of No 8 coal seam of No.2 mining area in Luling coal mine was presented.Different combination types of coal are established based on the the elastic parameters distribution range of various TDCs.Combining with the logging data and aeismic inversion method,the quantitative identification and division of different combination types of coal have been achieved.The results provide important theoretical and technical support for geophysical exploration of TDC and have a wider promotion and application prospects.