Abstract: In light of reservoirs with high temperature, high salinity and high heterogeneity, this paper proposed the techrique of using crosslinked polymer and pre crosslinked gel agent for complex displacement to further exploit remaining oil potential during high water-cut stage. These two profile control agents are of diferent oil displacement mechanisms and act as coordination of fooding and plugging.In order to testify the validity of the technique, field tests have been made in selected 9 well groups in Wenliu-25 east block, of which 7 have been fufilled, injecting agents of 7.922 6x10* m' in total. The results show higher injection pressure and improved sweep eficiency.The amount of cumulatively increased oil reaches 8305t, corresponding to 13 times that of simply using pre-crosslinked agent in effctiveness.

Key words: Zhongyaun oilfield, high temperature, high salinity, cross-linking agent, polymer, displacement mechanism, field test