The hydrocarbon-rich Qikou sag is one of the largest depositional sags in the Tertiary system in the Bohai Bay Basin. Its high percentage of negative tectonics, complex distribution of sedimental sand bodies, and diversified hydrocarbon reservoirs had challenged hydrocarbon explorers until CNPC secured a new breakthrough in exploring hydrocarbon-rich sags, as made a major innovation in geological prospecting technologies, resulting in significant exploration outcomes:

• Bottleneck-breaking acquisition technologies include integrated onshore and offshore acquisition, bidirectional non-vertical seismic sources and geophones in urban zones, network connection with multiple nodes arranged in large obstacle areas, and 3D seismic data acquisition in large modern ports and complex urban zones.
  
  
• A brand new, integrated geological interpretation mode based on super-large-area 3D seismic data lays a solid foundation for general study and exploration breakthroughs in the Qikou sag.
  
  
• New knowledge has been gained about the buried hill structure in an ancient uplift in the Dagang block and its flanks, unveiling the high potential of hydrocarbon exploration, many exploration strata, and reservoir accumulation and massive formation in multiple strata featuring "high oil & low gas and upper oil & lower gas" in sag slope zones of the structure. This knowledge provides new components for reservoir formation theory in hydrocarbon-rich sags in the Bohai Bay.
  
  
• A technological breakthrough in the periodic forecast of formation collapses has led to technological innovation in horizontal wells with extended reach.