Investigation of Chemical Composite Flooding Enhance Oil Recovery in Heavy Reservoirs After Steam Huff and Puff Cycles

After multiple steam huff‐and‐puff cycles, medium–high permeability heavy oil reservoirs are plagued by severe steam channeling, elevated water cut, and inadequate oil recovery. To mitigate this challenge, this study utilized a three‐dimensional (3D) visualization sand pack model to investigate the performance of slug chemical composite flooding (CCF) injection following multiple steam huff‐and‐puff cycles. The results demonstrate that compared with the post‐steam huff‐and‐puff stage, the CCF system enhanced oil recovery by 33.67%, achieved a maximum water cut reduction of 43.78%, and expanded the swept volume of low‐permeability regions by 21.40%. Findings reveal that the plugging agent effectively sealed preferential seepage channels, the oil‐displacement agent reduced the oil–water flow ratio, and the viscosity reducer significantly lowered crude oil viscosity, with the synergistic effect of these three agents collectively contributing to improved recovery efficiency. This study offers valuable insights into the application of CCF in enhancing oil recovery from medium–high permeability heavy oil reservoirs after multiple rounds of steam huff and puff thermal recovery.