混合菌系QZ-10对原油的作用性能表征及现场清防蜡应用

Effect of consortium QZ-10 on crude oil and its application in the removal of oil well paraffin

摘要:

【背景】油藏环境中呈单相液态的原油，在开采、运送的过程中由于温度、压力及流动条件的变化，石蜡不断从原油中析出，造成井筒、管线的结蜡。微生物清防蜡作为一项新兴的技术，受到广泛的关注，但是需要根据现场的环境条件施用合适的微生物清防蜡菌液。【目的】利用来源于青海油田盐碱油藏环境的混合菌系QZ-10，有效解决油井结蜡的问题并探究作用机理。【方法】针对混合菌系QZ-10开展表面张力/界面张力测定、乳化性能分析、降黏率和防蜡率测定、烃转化能力评估，来表征其性能特征，同时开展现场试验验证其实际清防蜡应用价值。【结果】混合菌系QZ-10菌液能将水-煤油界面张力降至1.21 mN/m，EI₂₄值为91.11%，降黏率达92.90%，防蜡率可达到90.00%，并且能够减少原油中的重质烃类、增加轻质烃组分、改善原油的品质。室内实验结果表明QZ-10菌液具有良好的降黏和乳化性能，展现出能够清除油井结蜡的潜力。选取青海油田中结蜡严重的油井，利用QZ-10菌液进行清防蜡作业，经过140 d的现场试验，结果显示试验的油井中80.95%油井除蜡效果明显，其中多口油井有显著增油效果，累计增油1 100 t。【结论】混合菌系QZ-10具有优良的油井清防蜡及驱油效果，应用前景广阔。

Abstract:

[Background] Under the high-temperature and-pressure condition,crude oil presents as a single-phase liquid.However,due to variations in temperature,pressure,and flow conditions during the mining and transportation processes,paraffin wax is continuously precipitated from the crude oil and deposits in the wellbore and pipelines.As an emerging technology,microbial wax removal has attracted wide attention.Nevertheless,the specific consortium applied needs to be determined according to the site conditions.[Objective] This study aims to use the consortium QZ-10 screened out from the saline-alkali reservoir environment in Qinghai oilfield to solve the problem of wax deposition in oil wells and investigate the mechanism.[Methods] The performance of QZ-10 was characterized based on surface tension/interfacial tension,EI₂₄ value,viscosity reduction rate,wax prevention rate,and hydrocarbon conversion ability.Finally,field trial was carried out to verify its actual effect on paraffin removal.[Results] The fermentation broth of QZ-10 could reduce the water-kerosene interfacial tension to 1.21 mN/m,and the EI₂₄ value was 91.11%.Besides,the viscosity reduction rate was measured as 92.90%,and the wax prevention rate could reach 90.00%.Furthermore,QZ-10 could degrade the heavy hydrocarbons in the crude oil,and increase the light hydrocarbon components,which would improve the quality of the crude oil.The results of laboratory experiments showed that the consortium QZ-10 reduced the viscosity of crude oil and emulsified the oil,and showed the potential to be applied in wax removal and prevention of oil well.The oil wells with severe wax deposition in Qinghai oilfield were selected for the field trial.After the injection of QZ-10 broth,paraffin wax was removed obviously in 80.95% of the tested oil wells after 140 days,and many of the tested oil wells had a significant increment in oil production,with a cumulative oil increment of 1 100 tons.[Conclusion] we demonstrated that the consortium QZ-10 could effectively remove paraffin wax deposited in oil wells and increase the oil production,which exhibited a broad application prospect.