适用于高温高盐低渗砂岩油藏的表面活性剂驱油体系

Surfactant Flooding System for High Temperature and High Salinity of Low Permeability Sandstone Reservoirs

为适应高温高盐低渗砂岩油藏提高采收率的需求,以新型阴—非离子表面活性剂SNH-10为主要处理剂,通过室内实验研究了一种耐温抗盐的表面活性剂驱油体系,并对其综合性能进行了评价。结果表明,该表面活性剂驱油体系在温度为140℃、矿化度为350g/L时,界面张力值仍能维持在10^(-3)mN/m数量级,具有良好的耐温抗盐性能;当体系含水率为70%时15h析水率仅为50%左右,具有良好的乳化性能;表面活性剂吸附在岩心表面能使其接触角增大,润湿性由强水湿向中性润湿方向转变;在天然岩心水驱后注入1.0PV的表面活性剂驱油体系,采收率提高幅度能够达到16%以上,具有良好的驱油效果。矿场试验结果表明,采取注表面活性剂驱油体系措施后,区块内的各生产井日产油量出现不同程度的上升现象,且含水率下降明显,达到了良好的施工效果。

In order to meet the need of improving oil recovery in sandstone reservoirs with high temperature,high salinity and low permeability,a new anionic-nonionic surfactant SNH-10 was used as the main treatment agent.A temperature-resistant and salt-resistant surfactant flooding system was studied through laboratory experiments,and its comprehensive performance was evaluated.The results show that the interfacial tension of the surfactant flooding system can be maintained in the order of 10-3 mN/m at 140 ℃ and 350 g/L of salinity,and it has good temperature and salt resistance.When the water content of the surfactant flooding system is 70%,the water precipitation rate is only about 50% at 15 h,which has good emulsifying performance.The contact angle of the surfactant adsorbed on the core surface can be increased and the wettability changes from strong to neutral water wettability.The oil displacement system injected with 1.0 PV surfactant after water flooding in natural core can increase oil recovery by more than 16% and has good oil displacement effect.The field test results show that the daily oil production of each production well in the block increases in varying degrees,and the water cut decreases obviously after adopting the measures of surfactant injection flooding system,which achieves good construction effect.