Wang Jiqian, Zhang Xuanyu, Han Han, Jia Yuqin, Zhang Hai, Jia Yanhui, Li Hui
State Key Laboratory of Heavy Oil Processing & Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580, China.
Research Institute of Oil and Gas Technology, Changqing Oilfield Company, CNPC, Xi'an, 710018, China.
Biodegradation. 2025 Oct 5;36(5):101. doi: 10.1007/s10532-025-10196-4.
Polymer flooding technology enhances crude oil recovery but generates a large amount of wastewater containing hydrolyzed polyacrylamide (HPAM) and HPAM residue in oil reservoirs, which induce serious environmental problems. Effective degradation of HPAM is highly required in oilfields, especially biodegradation technologies. Ten strains of HPAM degrading bacteria have been screened and identified from oilfield wastewater. An optimal HPAM biodegradation system of composite bacteria has been established based on two strains Agrobacterium pusense NMYGYA2 and Stutzerimonas balearica SCE1. The HPAM biodegradation performance of the composite bacteria has been improved through cultivation condition optimization. The highest HPAM removal rate of 81.2% could be achieved at the optimized condition with the addition of 800 mg·L urea, 500 mg·L glucose and 50 mg·L CaCl. The gel permeation chromatography results showed that the HPAM molecular weight decreased from 3.7 × 10 Da to 1.9 × 10 Da after the composite bacterial degradation. Fourier transform infrared spectroscopy analysis revealed the hydrolysis of NH group and the cleavage of C-C bond. Furthermore, the composite bacteria exhibited the ability to break down HPAM gels via biodegradation at temperatures up to 55 °C, indicating that they can be used to treat the blocking in reservoirs with a temperature < 55 °C and ground facilities.
聚合物驱油技术提高了原油采收率，但在油藏中产生了大量含有水解聚丙烯酰胺（HPAM）和HPAM残渣的废水，引发了严重的环境问题。油田迫切需要有效降解HPAM，尤其是生物降解技术。从油田废水中筛选并鉴定出10株HPAM降解菌。基于农杆菌NMYGYA2和巴利阿里斯氏菌SCE1两株菌建立了复合菌的最佳HPAM生物降解体系。通过优化培养条件提高了复合菌的HPAM生物降解性能。在添加800 mg·L尿素、500 mg·L葡萄糖和50 mg·L氯化钙的优化条件下，HPAM去除率最高可达81.2%。凝胶渗透色谱结果表明，复合菌降解后HPAM分子量从3.7×10 Da降至1.9×10 Da。傅里叶变换红外光谱分析揭示了NH基团的水解和C-C键的断裂。此外，复合菌在高达55℃的温度下能够通过生物降解分解HPAM凝胶，表明它们可用于处理温度<55℃的油藏堵塞和地面设施。
