关键词: 中低渗透油藏, 周期, 弱凝胶, 深部调驱

Abstract: Although the traditional profile control methods can displace and plug high reservoir and effectively use medium permeability reservoir. It is impossible to make effective use of low permeability reservoirs. The high formation pressure affects the injection volume and development effect of profile control and flooding agent. Taking medium⁃low permeability reservoirs as the research object, experimental study on weak gel and water alternating injection was carried out to reveal the mechanism and effect of cyclic deep profile control. The experimental results showed that the effect of cyclic deep profile control method was better than that of traditional profile control method. Compared with core No.1 (whole injection), the recovery of core No.2 (two rounds) was increased by 3.6%, and that of core No.3 (three rounds) by 5.3%. With the increase of injection cycles, the recovery rate increases, and the cyclic deep profile control method could improve the recovery rate of low permeability reservoir on the basis of effectively utilizing medium and high permeability layers. The field test results showed that after 2 rounds of gel deep flooding test, the cumulative oil volume in the experimental area was 1.53×104 t, and the recovery stage was 1.66%. The results have important practical significance for improving oil recovery in medium⁃low permeability reservoirs.

Key words: Low?medium permeability reservoir, Cyclic injection, Weak gel, Deep profile control