耐温耐盐抗剪切黄原胶强化泡沫体系性能

Performance of temperature-resistant, salinity-tolerant and shear-resistant xanthan gum enhanced foam system

关键词:  耐温  耐盐  抗剪切  黄原胶强化泡沫  再起泡能力 

Key words:  temperature resistance  salt tolerance  shear resistance  xanthan gum enhanced foam  repeating foaming ability

摘要:

针对轮南2TI油组高温高盐油藏条件,利用轮南2TI油组地层水、甜菜碱表面活性剂、黄原胶配制黄原胶强化泡沫体系,通过高温高压可视化泡沫发生仪分析起泡剂浓度、稳泡剂浓度、温度、矿化度、原油体积分数及剪切次数对泡沫性能的影响,利用显微镜对黄原胶强化泡沫微观形态进行表征。结果 表明,在起泡剂质量浓度2 000 mg/L、黄原胶质量浓度2 000 mg/L、温度120 ℃、矿化度200 572 mg/L、压力10 MPa条件下,黄原胶强化泡沫的起泡体积和析液半衰期分别为365 mL和58 min。随着黄原胶浓度增大,泡沫的起泡体积减小、半衰期增大,形成的泡沫更加均匀、气泡直径变小、液膜增厚,气泡直径及气泡个数变化速率减慢,黄原胶最佳使用质量浓度为2 000 mg/L。高温、高盐及原油均会对黄原胶强化泡沫的泡沫性能产生不利影响,但其可应用于温度110~130 ℃、矿化度180 000~240 000 mg/L、原油体积分数低于10%的苛刻油藏。随着剪切次数增加,泡沫体系的起泡体积增加,半衰期缩短,4次高速剪切后,黄原胶浓度为2 000 mg/L的强化泡沫体系的起泡体积增加率为13.6%,半衰期的保留率为77.6%,具有较强的再起泡能力和抗剪切性能。 

Abstract:

Aiming at the reservoir conditions of high temperature and high salinity in Lunnan 2TI oil group, the xanthan enhanced foam system was prepared by Lunnan 2TI formation brine, betaine surfactant and xanthan. This paper analysed the effect of foaming agent concentration, foam stabilizer concentration, temperature, salinity, volume fraction of oil and shearing times on foam performance by using high temperature and high pressure visualization foam meter, and the micromorphology of xanthan enhanced foam was characterized by microscope. The results showed that the foam volume and drainage half-life of xanthan enhanced foam were 365 mL and 58 min under the conditions of 2 000 mg/L foaming agent concentration, 2 000 mg/L xanthan concentration, 120 ℃, 200 572 mg/L salinity and 10 MPa. With xanthan concentration increased, foam volume decreased, half-life and liquid film thickness increased, the foam became uniformed and bubble size decreased, the change rate of bubble diameter and bubble number became slow, and xanthan optimum concentration was 2 000 mg/L. High temperature, high salt and oil would have negative effects on foam performance, but xanthan enhanced foam could be applied to the strict reservoir conditions with the temperature of 110-130 ℃, the salinity of 180 000-240 000 mg/L and oil volume fraction less than 10%. The foam volume increased and half-life decreased with the increasing of shearing time. After four times of high-speed shearing, the foam volume increment rate and half-life retention rate of xanthan enhanced foam were 13.6% and 77.6% respectively, the corresponding xanthan concentration was 2 000 mg/L, and it had strong repeating foaming ability and shear-resistant capacity.