塔中402CIII高温高盐油藏表面活性剂

Surfactant Flooding in Tazhong 402CIII High-Temperature and High-Salinity Reservoir

赵 冀 方吉超 周代余 赵健慧 崔仕提 戴彩丽 赵 红

ZHAO Ji FANG Ji-Chao ZHOU Dai-Yu ZHAO Jian-Hui CUI Shi-Ti DAI Cai-Li ZHAO Hong

针对塔中402CIII均质段油藏高温高盐高硬度的特点，优选出驱油用表面活性剂BS-12（甜菜碱），优化了使用浓度，考察了乳化、吸附及驱油性能。实验结果表明，在油藏条件下（温度110℃、矿化度11.52×104 mg/L、钙镁离子浓度7654 mg/L），BS-12溶液与地层水有良好的配伍性，质量分数0.03%~0.05%的BS-12溶液与塔中原油间的界面张力为1.5×10-2~5.2×10-2 mN/m。110℃老化30 d后的界面张力仍保持在10-2 mN/m数量级，热稳定性好。0.03%、0.05% BS-12溶液与原油形成的乳状液在放置12 h后趋于稳定，析水率分别为69%和50%，乳状液液滴分布稀疏，直径为0.3~1.0 μm。在水砂比为20:1时，0.05% BS-12在油砂表面的静态吸附量为6.592 mg/g。动态吸附量为4.938 mg/g，动态吸附滞留量为1.411 mg/g。岩心驱替实验表明，注入0.2%、0.3 PV表面活性剂后，采收率增幅可达4.14%。

On account of the characteristics of high-temperature, high-salinity and high hardness of homogeneous section of Tazhong 402CIII reservoir, betaine surfactant BS-12 and its applicable concentration were optimized. The performance of emulsification, adsorption and oil displacement was also evaluated. The results showed that under the reservoir condition (110℃, 11.52×104 mg/L salinity, 7654 mg/L Ca2+ and Mg2+), BS-12 solution had a good compatibility with formation water. The oil-water interfacial tension (IFT) was as low as 1.5×10-2—5.2×10-2 mN/m with BS-12 concentration ranging from 0.03% to 0.05%. The IFT maintained by 2 orders of magnitude after aging for 30 days at 110℃，which indicated good thermostability. The emulsion formed by 0.03% and 0.05% BS-12 solution and crude oil was stable after 12 h, and the water separation rate of surfactant systems was 69% and 50%, respectively. The droplets of emulsion showed a sparse distribution and its diameter ranged from 0.3 to 1.0 μm. The adsorption capacity on the surface of oil sands was tested with 20:1 mass ratio of liquid to solid. The static adsorption was 6.592 mg/g. The dynamic adsorption was 4.938 mg/g and its retention was 1.411 mg/g. Finally, core displacement experiment results showed that the oil recovery increment was 4.14% after injecting 0.3 PV 0.2% BS-12 surfactant.