普通稠油油藏组合式提高采收率技术—以渤海SZ36-1油田为例

Combined EOR Technology in Conventional Heavy Oil Reservoir—Taking SZ36-1 Oilfield in Bohai as an Example

曹 豹 张云宝 李 翔 卢祥国

CAO Bao ZHANG Yunbao LI Xiang LU Xiangguo

本文以渤海SZ36-1油田油藏地质特征和流体性质为研究对象，以黏度和采收率为评价指标，开展了调驱剂、封窜剂和冷采剂筛选和基本性能评价，进行了调驱、封窜、冷采以及“调驱剂+冷采剂”和“封窜剂+冷采剂”段塞组合措施增油效果物理模拟。结果表明，封窜剂（改性淀粉类，主剂浓度80000 g/L，辅剂浓度 2150 mg/L）较调驱剂（Cr3+聚合物凝胶，聚合物浓度4000 mg/L，聚合物与Cr3+质量比为180:1）具有良好的抗稀释和抗剪切性，按油水体积比1:5将冷采剂与原油混合后会形成油内相、水外相(O/W)乳状液，促使原油黏度降低（黏度为540 mPa·s的模拟原油经冷采剂乳化后的黏度降为3.4 mPa·s），渗流阻力减小。随岩心非均质性增强，水驱采收率减小，“调驱剂+冷采剂”和“封窜剂+冷采剂”段塞组合措施的增油效果提高，两个措施间采收率增幅差值增加，表明封窜剂转向作用效果增强，促使后续冷采剂更多地转向进入中低渗透层，原油降黏范围增加，作用效果增强。在高、中、低渗透率分别为6000×10-3μm2、2000×10-3μm2、200×10-3μm2的非均质岩心上，单独调驱、封窜和冷采、“调驱剂+冷采剂”和“封窜剂+冷采剂”段塞措施的提高采收率分别为25.5%、33.9%、6.1%、30.4%、39.9%，“封窜剂+冷采剂”复合段塞的液流转向效果较好，采收率增幅较大。

Taking reservoir and fluid of SZ36-1 Oilfield in Bohai as research object, the property of the profile control agent, channel sealing agent and cold production agent was evaluated using the value of viscosity and oil recovery as indicators, as well as the flooding performance of the above system separately and jointly was carried out. Results showed that the channel sealing agent (modified starch, main agent concentration 80000 mg/L, auxiliaries concentration 2150 mg/L) possessed better anti-dilution and anti-shear than common profile control agent (Cr3+ polymer gel, polymer concentration 4000 mg/L, mass ratio of polymer and Cr3+ 180:1) did. When Mixed at oil-water volume ratio 1:5 with cold production agent water solution, the crude oil was turned to be an oil-in-water emulsion, as a result, the viscosity and seepage resistance decreased accordingly, the oil viscosity decreased from 540 mPa·s to 3.4 mPa·s. With the increase of core heterogeneity, the oil recovery of water flooding decreased, however, the increments of oil recovery of combined measures(“profile control + cold production” , “channel sealing + cold production” ) increased. The increase of difference between “profile control + cold production” and “channel sealing + cold production” suggested that the better ability to the control profile of channel sealing agent forced more cold production agent to lower permeability layers and then the oil viscosity reduction area could be extended, which prominently improved flooding effect. In heterogeneous core with layer permeabilities of 6000×10-3μm2, 2000×10-3μm2, 200×10-3μm2, respectively, the increased recovery of profile control, channel sealing, cold production, and combined measures “profile control + cold production” and “channel sealing + cold production” was 25.5%, 33.9%, 6.1%, 30.4% and 39.9%, respectively, which suggested that the fluid profile control ability of “channel sealing + cold production” was better and had higher increased recovery.