Abstract: Aimed at such problems in the low permeability and complex fault block oil reservoirs in WENCHENG oilfield as uneven interlayers water absorption, apparent interlayers disturbance, severe downhole accidence, low degree of completion of injection and production, inadequate liquid supply in oil wells and the poor basis of stable production, the area distribution of residual oil is determined by enhancing geological study and improving the recognition of reservoirs and structures, and measurement of enhancing oil recovery is introduced, the effectiveness of recovery gets considerably improved, output has been increased in the area for three years, the recovery rate speeds up, the ratio of cost and return is 1:1.67. The analyzing index of the developed reservoirs is put forward technically and economically, the useful data are accumulated for the stable production in the developed reservoirs. 
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Key words: low permeability, residual oil, looking for the tendency, water drive control, stable production, Weicheng Oilfield