In order to explore the medium-high permeability reservoir with the permeability of （200~1 000）×10

-3

μm

2

the rheological behavior

thermal stability

viscoelasticity

and propagation performance of three kinds of polymer（linear polymer

hydrophobic association of partially hydrolyzed polyacrylamide（HAHPAM）

and active polymer） acting as the chemical flooding agents in Bohai Bay

are studied under the simulated reservoir condition. Results of rheological behavior indicate that

HAHPAM and active polymer solutions exhibit shear thickening at low shearing rate（simulation of deep reservoir

5.88~14.42 s

-1

）

and all three polymers show shear thinning at high shear rates（simulation of immediate vicinity of wellbore

149.9~223.4 s

-1

）. The oscillation frequency measurements show that HAHPAM and active polymer have larger elasticity

and their storage modulus are greater than their loss modulus. Results of sand-pack flow experiments show that linear polymer and active polymer can propagate better in porous media to achieve in-depth conformance control

whereas HAHPAM shows poor propagation behavior. The results of TEM and LPSA indicate that HAHPAM shows larger aggregation sizes（1.22 μm）

and the compatibility of linear polymer（0.28 μm） and active polymer（0.52 μm） with pore throats（4 μm） of reservoirs is better than that of HAHPAM. The results show that for the target reservoir

the polymer has better adaptability to the reservoir

followed by the linear polymer

while the hydrophobic association polymer has poor adaptability to the reservoir. The selection of polymer for polymer flooding in offshore reservoirs needs to consider the rheological properties of polymer

reservoir adaptability

and molecular microstructures so as to establish a multi-scale evaluation method for polymer screening. This study has a certain significance for screening polymer for polymer flooding in offshore oilfields.