文33块沙三上油藏弱敏感降压增注体系研究与性能评价

The Study and Performance Evaluation on Weak Sensitivity Reduced Pressure and Augmented Injection System for Oil Reservoirs in the Upper Member of Es3 in Block Wen 33

摘要: 针对文33块沙三上油藏注入压力高、酸化有效期短等问题，分析文33块沙三上油藏储层伤害主要原因是油藏具有较强速敏、中等水敏及酸敏，常规酸化易产生二次沉淀。开展了弱敏感降压增注体系主酸液与添加剂的筛选试验，确定了能够减小速敏、水敏及酸敏的主酸液与添加剂，该体系二次沉淀量为常规土酸的1/12。动态试验表明，该体系能有效解除近井污染以及因水敏、速敏使得黏土颗粒运移与膨胀而造成的地层堵塞。

Abstract: In consideration of the problems of high injection pressure and short valid period of acidizing in oil reservoirs in the Upper Member of Es3 of Block Wen 33, the mechanism of formation damage was studied and analyzed. The main reason was that the oil reservoir was with strong velocity sensitivity, moderate water sensitivity and acid sensitivity. Because it was easy to produce sec-ondary precipitation during conventional acidizing, experiments were carried out in the system with weak sensitivity reduced pressure and augmented injection. Main acid and additives were selected for reducing the velocity sensitivity, water sensitivity and acid sensitivity. For this fluid system, the secondary precipitation amount was 1/12 that of the conventional mud acid. The dy-namic experiments show that the fluid system can effectively remove near wellbore pollution and formation blockage resulted from clay particles migration and expansion caused by water sensitivity and velocity sensitivity.