The coal seam of Jurassic Xishanyao Formation in Houxia Basin,Xinjiang is generally 20～80 m thick.Due to the strong tectonic transformation of the intermountain basin,the content of coalbed methane and productivity of different wells shallower than 1 000 m vary greatly.In order to solve the problem of the control factors on coalbed methane,we carried out two-dimensional seismic structural in-terpretation and evolution research,and applied prestack seismic wave impedance inversion to predict gas content,and analyzed the relationship between structure and coalbed methane accumulation.The results show that the Yanshan and Himalayan thrust tectonic movements have caused gas reservoirs to suffer different degrees of damage.The evolution of medium and low rank coal from deep to shallow and the decrease of pressure lead to the generally low gas saturation of adsorbed gas in coal seams.Howev-er,due to the different sealing conditions of coal reservoirs for free gas,the gas content changes greatly,and is positively correlated with the single well productivity.The genesis of coalbed methane and the gas content including free gas and adsorbed gas change with the variation of tectonic unit,burial depth and formation occurrence.The gas content in the area of 7～13 m3/t is mainly composed of well-pre-served thermogenic gas-mixed gas,which is mainly distributed in the depression with the buried depth of 900～2 500 m.The areas with the gas content of less than 4 m3/t are distributed on the slope and convex structure of the basin edge,mainly secondary biogas.The gas content between 4～7 m3/t is dis-tributed in the transition zone between the above two.The gas content is high in the gentle slope with a dip angle of 3～7 degrees,and the gas content is low in the steep slope or large fault zone with a dip angle of 20～30 degrees.These complex structures play a decisive role in controlling the enrichment of coalbed methane and has important reference significance for exploration and development.
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