According to the poor water flood development effects of a typical low permeability multi-fractured block

and based on the dynamic simulation experiment system and the production technology of the fractured 3 D flat cores with low permeability of the unconventional reservoir

we carried out 9 groups of physical simulation flooding experiments to research the profile control effects of the fractured reservoir with low permeability in the different injection systems and injection rounds. The result showed that the weak gel system better fitted the fractured reservoir with low permeability

and plugged the micro fractures effectively. In addition

the optimized profile control system is composed of 0.1 % concentration of 8 million molecular weight polymer

0.1 % concentration of the profile system solution of cross linking agent

and the protection slug. It improved 31.35 % of the oil recovery by three injection rounds. Furthermore

the effects of the multi-round profile control decreased. The injected rounds should be selected reasonably according to the international oil price and the actual situation on site.