表面活性剂和碱对Cr3+聚丙烯酰胺凝胶成胶效果的影响及作用机理

在三元（或二元）复合驱过程中，调剖剂不可避免与表面活性剂和碱接触，因此碱和表面活性剂的性能可能会对调剖剂的性能造成影响。室内采用黏度计、动态光散射仪、扫描电镜和驱油实验装置，研究了碳酸钠、石油磺酸盐和脂肪醇聚氧乙烯聚氧丙烯醚对Cr3+聚合物凝胶调剖剂的黏度、分子聚集体尺寸、分子聚集体形态和调剖效果的影响。结果表明，石油磺酸盐和脂肪醇聚氧乙烯聚氧丙烯醚对Cr3+聚丙烯酰胺凝胶的黏度和分子聚集体尺寸几乎不影响；而Na2CO3的加入使Cr3+聚合物凝胶不成胶，且Cr3+聚丙烯酰胺凝胶成胶后加入Na2CO3会发生破胶现象，分子聚集体尺寸大幅下降，聚集体形态从大的团块状变成小的团块状，驱油过程中封堵效果明显变差。进一步分析发现，在碱性条件下，Cr3+聚丙烯酰胺凝胶难以发生交联反应，即使发生了交联也会发生解交联。

Effects of Surfactant and Alkali on the Gelation Performance of Cr3+ With HPAM and Its Action Mechanism

In the process of ASP (or binary compound) flooding, the contact betweenprofile control agents and surfactant and alkali is inevitable. Thus, alkali andsurfactant significantly affect the performance of profile control agent. The effects ofNa2CO3, petroleum sulfonate and polyoxyethylene polyoxypropylene ether on the viscosity,the size of molecular aggregate, molecular aggregate morphology and profile controlperformance of Cr3+ HPAM gel profile control agent  were studied, by using viscometer,dynamic light scattering, scanning electron microscopy and oil displacement experimentaldevice in laboratory. Results show that the gelation effect of petroleum sulfonate andpolyoxyethylene polyoxypropylene ether on Cr3+ HPAM gel is weak. In the presence ofNa2CO3, the Cr3+ HPAM gel can not be formed  and Cr3+ HPAM gel becomes destroyed afteradding Na2CO3. The size of molecular aggregates decreases significantly, the aggregatemorphology changes from large agglomerates to small agglomerates. The sealing effectduring the process of oil displacement deteriorates obviously. By further analysis, weconfirm that under the alkaline conditions, Cr3+ HPAM gel is difficult to happen via thecross-linking reaction.