Abstract: The Liaohe Depression has already entered the high maturity stage of exploration. The deepening exploration in mature exploration area cannot be limited to the scope of geophysical technology progress, drilling level improvement and revolution of oil and gas reservior stimulation technology, but should be reflected in the accurate grasping and innovative understanding of the objective existence of subsurface geological conditions. To address the problems that the conventional oil and gas exploration is difficult to achieve oil and gas discovery on a large scale and conventional exploration ideas are difficult to adapt to new unconventional oil and gas targets, the ideas of deepening geological understanding and reconstructing reservoir formation model were applied to innovate reservoir accumulation model in the Qingshui Depression of Western Sag to newly discover oil reserves of 2 800×10⁴t in rocky oil and gas reservoirs; a new "two-element“ evaluation model was created in Leijia area, which realized the surface-to-body transformation of unconventional oil and gas target evaluation; the exploration unit was reconstructed in the Member 3, Shahejie Formation of the Eastern Sag, and a new exploration unit was discovered and the Well X47 was deployed and implemented to obtain high production gas flow. A number of achievements were made during the exploration of oil and gas in mature exploration area of Liaohe Depression, which provided ideas and methodological reference for the exploration of similar type of mature area.

Key words: mature exploration area, deepening exploration, reservoir accumulation model, evaluation model, exploration unit, Liaohe Depression