摘要
针对北海油田轻质油砂岩油藏,对微生物提高采收率方法和机理进行了评价,以确定利用微生物提高采收率最好的方法。目前微生物提高原油采收率的机理主要有改变界面张力、油藏润湿性的变化、微生物封堵高渗区、微生物气驱等,由于油藏中的毛管数不同,在现场利用生物表面活性剂提高原油采收率无法达到理想效果;由于油藏微生物的生长得不到控制,无法稳定获得表面活性剂;油藏岩石对生物表面活性剂的吸附及其在现场的生物降解进一步限制了微生物提高采收率的效果。因此,微生物提高原油采收率方案需要利用系统的油藏工程原理进行评估,对于北海油田轻质油砂岩油藏微生物封堵是比较好的方法,1 kg营养物质可增产1.3～2.6 L原油。
The current method and mechanism of microbial enhanced oil recovery for Light oil sandstone reservoirs in North Sea oilfield, were summarized in this paper, which were evaluated to determine the best method of microbial enhanced oil recovery. The microbial enhanced oil recovery mechanisms include changing the interface tension, reservoir wettability change, microbial plugging hypertonic district, microbial gas drive. Because of different capillary number for the reservoir, incremental oil recovery by biosurfactant production in situ would not reach ideal conditions. The achievable yields would be lower because the microbiol in the reservoir would not be controllable to achieve sustained surfactant production. Losses of biosurfactants by adsorption to reservoir rocks and in situ biodegradation would further limit performance. So the system of reservoir engineering theory was needed to assess the programm of microbial enhanced oil recovery. For light oil sandstone reservoir in North Sea, microbial plugging is a good method, 1.3 - 2.6 L crude oil can be increased when adding 1 kg of nutrient.
