Abstract: In viewing of the deteriorating waterflooding effects, escalating water cut and accelerating production decline in Qiwu fault block in Xuzhuang oilfield, fine reservoir description and inter - well chemical tracer monitoring are performed. Based on deep understanding of remaining oil distribution and water channel changes, a massive deep profile correction plan is drawn up and implemented. Six deep profile operations are carried out in 4 water injection wells and the average amount profile correction agents used in single operation is 3,945m3. Eight corresponding wells respond successively leading to a cumulative incremental oil production of 6,900 tons.