为了揭示疏水缔合聚合物三元复合体系在多孔介质长距离运移过程中流度控制能力的变化规律,采用自主设计研制的30 m长的物理填砂模型进行疏水缔合聚合物三元复合体系(简称缔合ASP三元体系)室内驱油实验,并与同等条件下常规三元复合体系(常规ASP三元体系)的驱油效果作对比,分析流度控制能力随运移距离的变化情况。研究结果表明,在平均渗透率K_g=872×10^(-3)μm^2的物理填砂模型中,缔合ASP三元体系在缔合状态下注入能力较差,在长距离运移条件下对深部的流度控制能力不如常规ASP三元体系。缔合ASP三元体系在近井地带的表观黏度测定值较高,但压力提高效果反而较弱,这是由于缔合聚合物分子间所形成的空间结构在孔喉中难以保持。二类油层条件下,注入的驱替相的黏度至少需要达到23 m Pa·s才能对小孔道中的流体产生有效波及,本实验条件下三元段塞维持黏度该值的距离仅为注采井距的40%左右。
The purpose of this experimental study is to evaluate the feasibility and oil recovery efficiency of continuous N_(2) injection in a multi-well fractured-cavity reservoir.In this study,the similar criterion of physical simulation was firstly discussed.In order to reveal the mechanism of remaining oil startup and production performance characteristic by continuous N_(2) injection,a visualized twodimensional fractured-cavity model and a three-dimensional pressure resistant model were designed and fabricated respectively based on the similar theory.And the 2D visualized physical experiments and 3D physical experiments were performed with the simulated oil and brine reservoir samples in Tahe oilfield.Four groups of experiments in 2D and 3D model were performed,each of which included bottom water depletion driving,water injection and N_(2) injection.The 2D visualized experiments indicated the main mechanism of N_(2) developing remaining oil was to occupy the high position and replace the attic oil due to gravitational differentiation.Furthermore,both the 2D and 3D experiments demonstrated that higher oil recovery factor could be achieved if N_(2) was injected through high positional wells.The 3D physical model is closer to the real reservoir condition,so the production performance can reflect the real field production process.This paper confirmed the efficiency of continuous N2 flooding in the light oil saturated fractured-cavity reservoir.
为明确碱-表面活性剂-聚合物(ASP)三元复合体系在非超低界面张力下的乳化作用及其对提高采收率的影响,以综合乳化性能指数Ie为指标,评价了5种表面活性剂的乳化性能,筛选出了一种界面张力非超低但乳化性能优良的体系,并通过平面径向流模型驱油实验研究了该体系的驱油效果。研究结果表明:所考察表面活性剂的综合乳化性能Ie由强到弱依次为OP-10、HABS(重烷基苯磺酸盐)、BS-12(十二烷基二甲基胺乙内酯)、AES(脂肪醇聚氧乙烯醚硫酸钠)和OP-4;碱质量分数为0.3%时,ASP三元复合体系综合乳化性能最优。优选的乳化性能优良的非超低界面张力ASP三元复合体系配方为:Na OH质量分数0.3%、表面活性剂(60%OP-10+40%HABS)的质量分数0.3%、聚合物(部分水解聚丙烯酰胺,相对分子量2000×104)质量浓度1500 mg/L,该体系的黏度为42.9 m Pa·s(45℃、转速6 r/min),与模拟油间的界面张力为0.0415 m N/m,综合乳化性能Ie为0.688,在驱油过程中能够扩大波及体积且可提高波及范围内的驱油效率,提高采收率效果不亚于常规超低界面张力体系。
