The practice and understanding of seismic exploration technology of shallow coal seams in Zhijin area, Guizhou Province

Seismic data from Zhijin area have the characteristics of low signal-to-noise ratio, poor consistency of events, restricting the exploration and development of coalbed methane. The extensively distributed carbonate and shallow burial depth of Longtan Formation of Permian are the main causes for the poor seismic imaging quality. Practice shows that the multiple channel array receiving technology of analog geophones, based on digital box wave survey, had good noise suppression effect, the excitation technology matched with lithology, well depth and charge mass, based on the maximum SNR of coal seam reflection, enhanced the seismic excitation efficiency, observation of broad lines, configuration technique of geophone traces with small interval were the effective methods to improve 2D seismic imaging, 3D seismic observation technology with small trace interval, small line interval, dense shooting and high horizontal-vertical ratio enhanced significantly the quality of seam data. The technology is suitable for seismic acquisition of shallow coal seams in mountainous limestone-exposed areas.