ANALYSIS OF WATERFLOOD DEVELOPMENT IN Es_3~(2+3) RESERVOIR OF LIUZHONG BLOCK IN LIUZAN OILFIELD

Liuzhong Block,one of major blocks in Liuzan oilfield,is characterized by development of Es32+3 reservoir.The development of natural energy was used in early phase,with duly water injection.As the progressive development goes on,some problems were emerged,such as obvious plane conflict and interlamination contradiction,decline of crude oil production and fast increment of water cut.Since 2002,in the block,the geological understanding has been enhanced,the concept of water injection has been changed to overall study on water injection efficiency and reinforcement of water injection management,focusing on the improvement of well pattern and injection-production system and aiming to build an injection-production balance.Through using a series of measures including separated water injection,profile adjustment,polymer flooding,and water plugging,better development effects have been realized by the recovering formation energy and controlling water cut.