SZ36-1 Oilfield was put into production in 1993 and underwent well pattern infilling in 2009-2010. After that, the well pattern type was changed from inverted nine-spot pattern to line drive pattern. Based on the dynamic data as of June 2016, eight development indexes were calculated as follows: recovery factor 43.04%, degree of control of waterflooding reserves 93.08%, producing degree of waterflooding reserves 90.06%, water cut rising rate 0.8%, decline rate 1.01%/a, stage water storage rate evaluation coefficient 0.654, stage water drive index 1.721, average formation pressure 10.11MPa, and pressure maintenance level 73.3%. In accordance with CNOOC’s industrial standards, the recovery factor, degree of control of waterflooding reserves, producing degree of waterflooding reserves, water cut rising rate, decline rate, and stage water storage rate after infilling belong to Class I. Determined by the industrial standard method, the development effect of SZ36-1 Oilfield after overall infilling also belongs to Class I. In SZ36-1 Oilfield, the water cut is 74.04%, and the recovery percent is 23.11%, but the forecasted recovery factor is 43.04%, therefore, there is still a large residual oil potential.