For complex fault-block oilfields, geological characteristics such as reservoir abundance and oil–water interface are quite different in different fault-block oilfields, which increases the difficulty for development effect evaluation and dynamic adjustment of development plans. Water energy is an important evaluation index in the process of reservoir development, and it is an important basis for later development adjustment. In this paper, a fault block oilfield A in the north of Song-Liao Basin is taken as an example, and the activity degree of edge and bottom water and water influx in 20 blocks of oilfield A are evaluated by using the material balance method. It is concluded that the energy of edge and bottom water in the three blocks is more abundant, and the edge and bottom water in the first block is the most active. However, Block 1 has a short period of water-free oil production during the generation process, and its water cut rises rapidly, which has obvious water invasion characteristics. Therefore, the corresponding water invasion control measures are put forward for Block 1, including fine water injection plan adjustment, water shutoff measures and production system adjustment. The study has certain reference significance for the treatment of active edge and bottom water blocks in complex fault-block reservoirs and the continuous improvement of oilfield development effects.