可循环微泡沫钻井液技术研究与应用

Study and application of circular micro-foam drilling fluid technology

针对在低压裂缝性潜山油层和砂岩油层的勘探开发中,使用常规水基钻井液存在严重漏失问题,钻井工艺研究院研制出了抗高温可循环微泡沫钻井液体系。室内对发泡剂、稳泡剂用量以及该钻井液的稳定性、抗温性、抗污染性和油气层保护进行了评价。结果表明,该体系起泡性能好,微泡沫基液与气体接触后可产生大量颗粒较细的微泡沫,徽泡沫稳定性强,在长时间循环和高温条件下性能稳定,抗污染能力强,与储层流体及钻井液处理荆配伍性好;配制微泡沫钻井液,发泡荆最佳用量为0.4％～1.0％,稳泡剂最佳用量为0.1％～0.3％。现场应用表明。微泡沫钻井液具有低密度的特点,在三开钻进过程中相对稳定,解决了在低压储层钻井时遇到的井漏问题,避免了因井漏引起的储层损害,达到了保护油层的目的;该钻井液具有较强的携砂能力,岩屑返出正常,完全满足了开发低压油气层工程和地质需要。

During the exploration and development of low-pressured fractured buried hill reservoir and sandstone reservoir, serious lost circulation was encountered when using the conventional water based drilling fluid. High temperature tolerant circular micro-foam drilling fluid system was developed by Drill ing Tech. Research Inst. of Huabei Petroleum Administration. Laboratory evaluations were conducted on the dosage of foaming agent and foam stabilizer, and the stability, temperature tolerance, contamination resistance and reservoir protection of the drilling fluid. Testing results showed that the system has good foaming capability, large amount of fine micro-foam could be formed when the base fluid contacted with air; the foam has good stability, and the foam could keep stable in high temperature and long time circulation; the system also has high contamination resistance, and the formation fluid has good compatibility with drilling fluid additives. When batching the micro foam drilling fluid, the best adding amounts of foa-ming agent and foam stabilizer are 0. 4% - 1. 0% and 0. 1%-0. 3% respectively. Field using showed that the micro-foam drilling fluid has the characteristic of low density, and in drilling the third section, it kept stable and solved the problem of lost circulation when drilling the low-pressured reservoir, thus avoided formation damage and protected reservoir. The drilling fluid has good cuttings transportation with most of the cuttings returned to the surface, which totally met the engineering and geological needs of developing low-pressured oil and gas reservoir.