Abstract:

The novel granular nutrients based on starch-cellulose for indigenous microbial flooding were developed. The activating process of the novel nutrient to the indigenous microorganism communities was investigated. The plugging and displacing effects of nutrients were evaluated by core-flooding experiments. The plugging and displacing mechanism of the nutrients were discussed. The research results showed that the indigenous bacterial populations could be effectively activated by the novel nutrients and significantly grown under the conditions of oxygen and no oxygen. The hydrocarbon-oxidizing bacteria and ferment bacteria were the dominant population. The novel nutrients could be metabolized to produce the useful bio-surfactant (rhamnolipid with fatty acids of saturated or unsaturated alkyl chain between C₈ and C₁₂) and bio-gas (CH₄ and CO₂) to emulsify oil. The core oil-displacement experiments of the heterogeneous model showed that the novel nutrient system could improve the oil-displacement efficiency and greatly increase the volumetric sweep efficiency. The recovery efficiency was improved by 12%~20% of OOIP under the experiment conditions. Field test suggested that the novel nutrients based on starch-cellulose could effectively plug off higher-permeability zones and divert the injected fluid into the low-permeability zones. The oil production rate increased remarkably with the declined water cut and the input-output ratio was more than 1 to 9.

Key words: indigenous microorganism, nutrients, plugging mechanism, bio-surfactant, sweep efficiency

摘要：

开发了以淀粉-纤维素为基础的颗粒状本源微生物驱油营养剂，研究了营养剂对菌群的激活过程，并利用不同岩心模型评价了体系的封堵作用与驱油效果，探讨了该营养体系的调驱机理。结果表明，该体系在有氧和无氧条件下均能有效激活本源菌群，主要是烃类氧化菌和发酵细菌。微生物利用营养体系可产生表面活性物质（带C₈—C₁₂ 长链脂肪酸的鼠李糖脂）和生物气（CH₄和CO₂），对原油有较好的乳化作用。非均质模型驱油结果表明，该体系不仅具有提高洗油效率的作用，同时可大幅提高波及效率，实验条件下可提高采收率12%~20%。现场试验表明，新体系能有效地封堵高渗透层，改变水驱方向，降水增油效果显著，投入产出比达1∶9以上。

关键词: 本源微生物, 营养剂, 封堵机理, 生物表面活性剂, 波及效率