【摘要】 实验研究了大庆油田所用ASP三元复合驱替液的驱油效率与碱浓度之间的关系。在45℃(大庆油藏温度)下,随碱浓度增大(0～1.5×104mg/L),NaOH/ORS 41/HPAM蒸馏水溶液在全部实验剪切速率范围内的粘度及在全部实验剪切振荡频率范围内的损耗模量、储能模量、松弛时间均不断下降,表明溶液粘弹性不断减小;溶液与原油间的动态界面张力(60min稳定值)基本上不受聚合物浓度的影响,而随碱浓度的增大而下降,在碱浓度≥8.0×103mg/L时达到超低值(10-3mN/m)。用注入水(矿化度3.7×103mg/L)配制的相同ORS 41和HPAM浓度、不同碱浓度(0、3.0×103、6.0×103、1.2×104mg/L)的ASP溶液在不同岩心上的驱油效率变化规律有很大不同,水驱后提高采收率的幅度,在人造非均质岩心上在碱浓度3.0×103和6.0×103mg/L时达到高峰值,在标准长度和加长至两倍长度的两组天然均质岩心上随碱浓度增大而逐步提高,在碱浓度增大至1.2×104mg/L时略有降低。高碱浓度ASP溶液尽管具有超低界面张力,但由于粘度低、粘弹性低,驱油效率也低;油水界面张力在10-1～10-2mN/m、粘弹性(和粘度)较高的ASP溶液在岩心上驱油效率最高;超低界面张力不是绝对必要的。图4表2参11。更多还原

【Abstract】 The oil displacement efficiency of the ASP combinational flooding solution of varying alkaline concentration used at Daqing is studied experimentally. It is shown that for NaOH/ORS41/HPAM solution in distilled water with alkaline concentration varying from 0 to 1.5×104 mg/L at 45℃ (reservoir temperature), the apparent viscosity, μa, in the experimental shear rate range and the loss and storage moduli, G″ and G′, and the relaxation time, λ, in the experimental oscillation shear frequency range decrease continuously, which indicate weakening of the viscoelastic behavior; the dynamic interfacial tension between the ASP solution of ORS41 concentration 3.0×103 mg/L and crude oil (stable value at 60 min) is not influenced by varying polymer concentration but decreases with decreasing alkanine concentration and reaches ultralow value, 10-3 mN/m, at alkaline concentration≥0.8×103 mg/L. For ASP solution of equal ORS41 and HPAM concentrations and varying NaOH concentration (0,3.0×103, 6.0×103, and 1.2×104 mg/L), the changes of displacement efficiency are dissimilar on different cores: the enhancement in oil recovery after waterflood reaches peak value at NaOH concentration 3.0×103 and 6.0×103 mg/L on artificial inhomogeneous cores and gradually increases with increasing NaOH concentration and slightly decreases at NaOH concentration 1.2×104 mg/L. For ASP solution of high NaOH concentration, the oil disptacement efficiency is low because of low viscosity and viscoelasticity, in spite of ultralow interfacial tension; the highest displacement efficiency is observed with ASP solution of interfacial tension 10-1-10-2 mN/m and of higher elasticity and viscosity; the ultralow interfacial tension is not necessary absolutely.更多还原