The piedmont of the complex mountain in southwestern Tarim Basin,located at the intersection of the West Kunlun oro-genic belt and the Tianshan orogenic belt,is one of the scarce extremely-challenging exploration areas in China.The high-dip angle and fragmentized underground structures induced by strong compression of the two orogenic belts and the complex and varying near-surface seismic geological conditions jointly lead to extremely low signal-to-noise ratio(SNR)of raw seismic data,bringing difficulty to the imaging of the underground structures.For this reason,there has been no substantial breakthroughs in oil and gas exploration in this area.In recent years,great efforts have been devoted to seismic exploration.In view of seismic acquisition,near-surface seismic survey is strengthened,the shooting and receiving parameters are optimized,the geometry design is updated,and the beam seismic and high-density wide-azimuth 3D seismic techniques are upgraded.In view of seismic processing,some attempts are made in constrained first arrival tomography inversion,strong energy noise suppression at"black triangle belt"of the seismic records,true surface velocity modeling,and depth migration imaging.By virtue of these efforts,the quality of seismic data has been continuously improved,and many drilling targets have been discovered.Two major breakthroughs have been made in the Jurassic sandstone and the Carboniferous-Permian carbonate rocks for the first time,opening up a new stage of oil and gas exploration in the piedmont in southwestern Tarim Basin.
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