新型产甲烷菌系提高极限含水油藏采收率技术

Enhancing oil recovery of ultimate water-cut reservoirs with a novel methane-producing bacterial strain

丁明山 林军章 冯云 孙楠 王冠 巴燕 汪卫东

DING Mingshan LIN Junzhang FENG Yun SUN Nan WANG Guan BA Yan WANG Weidong

1. 中国石化 微生物采油重点实验室, 山东 东营 257000; 2. 中国石化 胜利油田分公司 石油工程技术研究院, 山东 东营 257000; 3. 中国石化 胜利油田分公司 孤东采油厂, 山东 东营 257237

1. Key Laboratory of Microbial Enhanced Oil Recovery, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257000, China; 2. Research Institute of Petroleum Engineering and Technology, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257000, China; 3. Gudong Oil Production Plant, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257237, China

我国东部老油田已整体进入特高含水开发阶段，呈含水上升快、采油速度低、水驱效益低等开发特征，现有提高采收率技术已无法实现原油的经济采出，亟需建立接替技术。为此，以胜利油田某聚驱后油藏为试验区，开展了油藏菌群结构分析、新型产甲烷菌系的激活产气、油藏适应性及驱油性能研究，探索新型产甲烷菌系在这类油藏的应用潜力。研究结果显示，试验区油藏具有丰富的石油烃降解菌，有利于生物气化技术的实施。模拟试验区油藏条件下，新型产甲烷菌系与油藏内源微生物有较好的相容性，90 d每克原油的产气量达到3.12 mmol，是单独激活油藏微生物产气量的4.5倍，且产生的气体中甲烷气占比达到78%。菌群结构分析显示，新型产甲烷菌系占比达到35.9%，是产气速率大幅提升的关键。适应性研究结果显示，在油藏温度低于65 ℃、原油黏度小于1 356 mPa·s条件下，新型产甲烷菌系均展示了良好的产气性能。利用实验室设计的物理模型，评价了该菌系产气提高驱油性能，结果显示，注入该菌系后产气作用有效动用了模型顶部的剩余油，极限含水条件下驱油效率提高5.4个百分点；在此基础上提出了生物气化技术提高极限含水油藏采收率的机理。

Most of the old oil fields in eastern China are now in the ultra-high water-cut development stage characte-rized by a rapid increase in water-cut,low oil recovery rate and inefficient water flooding. The existing technologies for enhancing oil recovery are no longer economically viable for crude oil extraction,necessitating the development of alternative techniques.This study focuses on a post-polymer-flooding oil reservoir in the Shengli Oil Field as an experimental area. The analysis of the reservoir microbial community structure and the study on the activation, reservoir adaptability and oil displacement performance of the novel methane-producing bacterial strain were conducted to explore its application potential in such reservoirs. The results showed a rich population of petroleum hydrocarbon degrading bacteria in the experimental area,which is conducive to the implementation of biogasification technology. Under simulated reservoir conditions,the novel methane-producing bacterial strain had good compatibility with the indigenous microorganism in the reservoir,achieving a gas production rate of 3.12 mmol/g oil after 90 days. This rate was 4.5 times higher than that from activating reservoir microorganisms alone,with methane accounting for 78% of the generated gas. Microbial community structure analysis revealed that the newly discoverd methane-producing bacterial strain comprised 35.9% of the community, playing a vital role in the significant increase in gas production rate. An adaptability study demonstrated that this bacterial strain exhibited exceptional gas production performance at reservoir temperatures below 65 ℃ and crude oil viscosities less than 1 356 mPa·s. Utilizing a laboratory-designed physical model,the impact of the bacterial strain on enhancing oil displacement performance was assessed. These results showed effective mobilization of residual oil at the model’s top after bacterial strain injection, leading to a 5.4 percentage point increase in oil displacement efficiency under ultimate water-cut conditions. These findings support the proposal of using biogasification technology to enhance oil recovery in ultimate water-cut reservoirs.

国家重点研发计划“油田采油生物制剂研发及应用”(2022YFC2105200)资助。

https://doi.org/10.11781/sysydz202402412