大庆油区三元复合驱耐碱性调剖剂的研制与段塞组合优化

针对大庆油区三元复合驱区块中后期含水上升快,不同渗透率油层动用差异大,注入液无效循环的问题,开展了三元复合驱耐碱性调剖剂的研制。通过对交联剂种类及质量分数、聚合物质量浓度及相对分子质量和聚合物溶液熟化时间等的筛选,并结合正交试验,研制出了适用于三元复合驱深部调剖的调剖剂配方,该配方由相对分子质量为2 500×104且质量浓度为2 000 mg/L的聚合物、质量分数为0.15%的离子型交联剂YH-1、质量分数分别为0.1%和0.08%的有机交联剂THM-1和THM-2以及质量分数为0.2%的稳定剂、质量分数为0.1%的除氧剂组成,形成的调剖剂成胶时间为102 h,成胶粘度为3 510 m Pa·s,稳定时间大于60 d,抗盐性好,对三元复合体系界面张力影响不大。该调剖剂应用于三元复合驱调剖时,能够更好地发挥注入液驱替中、低渗透层的作用,比不应用调剖剂的三元复合驱提高采收率4%左右。数值模拟结果表明,在注入调剖剂前,加入0.01倍孔隙体积的前置聚合物段塞,能够使调剖剂保持更好的成胶性能,效果更好。

Preparation and plug optimization of profile control agent in ASP flooding

Water cut rises quickly in the middle and later periods of ASP flooding in Daqing oilfield, which leads to considerable discrepancies in development situations of reservoirs with different permeability and invalid injected liquid cycle. Aiming at these problems, the preparation of resisted alkali profile control agent in ASP flooding was carried out. Through choosing crosslinking agent and crosslinking agent concentration, polymer concentration and molecular weight and polymer maturing time, along with orthogonal experiment, the resisted alkali profile control agent formula fitting for ASP flooding was prepared. The formula was made up of polymer, ion crosslinking agent, organic crosslinking agent, stabilizer and deoxidant (polymer: molecular weight was 2 500×104 and its concentration was 2 000 mg/L; metallic crosslinking agent: YH-1 and its concentration was 0.15%; organic chromium: THM-1, THM-2 and their concentrations were 0.1%, 0.08% respectively; stabilizing agent: concentration was 0.2%; deoxidant: concentration was 0.1%). The gelation time was 102 hours and is adjustable. The viscosity after gelatinizing was 3 510 mPa?s. The stability time of gel was greater than 60 days. It had good salt resistance and small impact on interfacial tension of ASP system. When the profile control agent was applied to the process of ASP flooding, it can enable more injection liquid to displace low and medium permeable layer, and it can enhance oil recovery by 4% compared with that of ASP flooding without profile control agent. The numerical simulation results showed that the profile agent could keep better gelation performance by adding a small amount of pre-polymer slug before injecting profile control agent to achieve a better development effect.