Abstract: Oil and gas with high flow rate is produced at Niudong1 well, and this is PetroChina's another great breakthrough in exploration of buried hill in Jizhong Depression of the Bohai Bay Basin, after the discovery of Renqiu buried hill in 1976. Exploration for oil and gas in deeply buried hill of Niudong1 well took 33 years and experienced six exploration stages. Several generations of explorationists kept on striving to make technological breakthrough in geophysical exploration, continuously built and improved geological structure of buried hill, finally confirmed buried hill morphology after processing of the second 3D seismic data acquisition and prestack depth migration, and calibrated Niudong1 well. The deepest high-yield oil and gas reservoir in the Bohai Bay Basin and even East China was discovered then, opening up new dimension in exploration of deeply buried hill in Jizhong Depression. This is of milestone significance to promoting deep exploration of the Bohai Bay Basin.

Key words: buried-hill zone, risk exploration, high-yield oil and gas reservoir, terrace-fault buried hill, strategic discovery, breakthrough significance