产酸微生物作用大庆原油改善化学驱效果研究

The acid-producing microorganisms to increase the acid number of daqing crude and thus to modify the chemical flooding

从大庆油层水中筛选出短短芽孢杆菌HT和蜡状芽孢杆菌HP,在兼性厌氧条件下,利用原油烃为唯一碳源,降解原油中重质成分,尤其是高碳链(20碳以上)饱和烃,产生大量的胞外有机酸,可使原油酸值平均升高10倍以上.微生物作用原油后,产生的大量有机酸,在碱性条件下能与合成表面活性剂产生很好的协同作用,使微生物作用后原油与现有三元复合体系形成更低的界面张力,平均比未作用原油体系界面张力降低一个数量级,达到10-4mN/m数量级.室内天然岩心驱油评价结果表明,微生物-三元复合驱结合可比单独三元复合驱驱油效率增加近10%(OOIP).这一技术对大庆主力油田提高可采储量将会发挥巨大的作用.

Under aerobic or facultative aerobic conditions, the bacteria of HT （ Brevibacillus brevis） and HP （ Bacillus cereus） selected from daqing formation water which use hydrocarbon as the sole carbon source, can degrade heavy components in the crude oil, especially the saturation hydrocarbon with over 20 carbons. The extracellular organic acids produced through the process of oil degradation can increase averagely the acid number of crude oil by above 10 times. The study also indicates that at the presence of alkali, these organic acids can well synergize with synthesized surfactants, which reduces the IFT between the ASP system and the degraded crude one order of magnitude lower than the IFT before degradation, reaching 10^-4mN/m. The laboratory flooding experiment on natural cores demonstrates that the combination technology of microorganism - ASP flooding can enhance about 10% more original oil in place （OOIP） than the individual ASP flooding, which will play a great role in increasing the recoverable reseryes in Daqing oil field.