Abstract: After entering highly mature exploration, the Liaohe oilfield should be finely explored in the middle and shallow reservoirs to improve exploration efficiency. In recent years, to adapt the conditions such as highly explored middle and shallow reservoirs, small fault blocks, thin sandstone layers and complex reservoir development in the Liaohe depression, a series of work have been carried out, involving selection of good zones, innovation of geological understanding, fine target characterization, fine interpretation of micro-relief structures instead of massive structures, combined pre-stack and post-stack seismic inversion instead of post-stack seismic inversion, multi-disciplinary research on exploration potentials, rapid production capacity construction through integrated exploration and development. The implementation of the measures above made new discoveries of several high-quality reservoirs with reserves at 10 million-ton scale in the surroundings and new formations of old fields. Exploration practice shows that to make more discoveries in the middle and shallow reservoirs is important for efficient exploration.

Key words: middle and shallow reservoirs, fine exploration, efficient exploration, Liaohe depression