适合低渗透砂岩油层的新型磺基甜菜碱表面活性剂的研究

A New Sulphobetaine as Surfactant for EOR in Low Permeability Sandstone Reservoirs

报道了以中部有芳环的长链烷基为亲油基的一种新的驱油用磺基甜菜碱SLB-13，给出了化学结构，讨论了亲油基最佳结构。45℃时该表面活性剂水溶液在0．05～3．0g／L宽浓度范围可产生超低（10^-3mN／m）油水界面张力。在尺寸4．5×4．5×3．0（cm）、纵向渗透率变异系数0．72、平均渗透率29×10^-3～45×10^-3μm^2的石英砂胶结岩心上，使用黏度10mPa·s的模拟油，在45℃考察了水驱之后注入0．3PV化学剂段塞提高采收率的幅度及段塞注入性和提高波及体积能力（通过Ps／Pw值即注剂注水最大压差比），结果如下。1．0和3．0（g／L）SLB-13段塞仅提高采收率4．62％和3．41％，Ps／Pw值为0．37和0．43，注入性好但不能提高波及体积；0．4HPAM（M=4．8×10^6）段塞提高采收率7．22％，Ps／Pw=1．05；3．0＋0．4、1．0＋0．4、1．0＋0．8SLB-13＋HPAM复合段塞分别提高采收率8．68％、11．74％、16．20％，Ps／Pw值分别为1．04、1．37、2．30，最佳段塞为1．0＋0．4S阻13＋HPAM。SLB-13可用于大庆低渗油藏提高采收率。表3参6。

A new sulfobetaine as sufactant for EOR having lipophilic long-chain alkyl with aromatic ring in middle position is presented and notated as SLB-13. Its chemical structure is given and optimal chemical structures of lipophilic groups are discussed. Aqueous SLB-13 solution creates ultralow water/oil interracial tension of magnititude 10.3 mN/m in a wide concentration range 0.05--3.0 g/ L at 45℃. On epoxy cemented quartz cores 4.5 × 4.5 ×3.0 （cm）, of average permeability 29 × 10^-3 --45 × 10^-3 μm2 and vertical permeability variation coefficient 0.72 and with a simulation oil of viscosity 10 mPa.s used, the enhancement in oil recovery （EiOR） by various chemical slugs in size 0.3 PV and their injectivity and sweeping efficiency in terms of injection pressure ratio of chemical slug to water, Ps/Pw, are investigated at 45℃ after the water flood phased ended and following results are obtained. An EiOR of 4.62% and 3.41% is obtained with 1.0 and 3.0 （g/L） SLB-13 slugs, which are easily injectable but have poor sweeping power as shown by Ps/Pw ratio 0.37 and 0.43. An EiOR of 7.22% and Ps/Pw ratio of 1.05 are obtained with 0.4 HPAM （of M = 4.8 × 10^6） slug. 3.0＋0.4,1.0＋0.4, and 1.0＋0.8 combinational SLB-13 ＋ HPAM slugs give EiOR of 8.68% ,11.74%, and 16.20% and Ps/Pw ratio of 1.04, 1.37, and 2.30, respectively. The optimal and proper slug appears to be 1.0 ＋ 0.4 SLB-13 ＋ HPAM. Thus, SLB-13 can be used as surfactant for EOR in low permeability sandstone reservoirs in Daqing.