聚合物驱后油藏驱油菌种的性能和作用机理

从大庆油田筛选到聚合物降解菌种JHW-31,将菌种置于45℃、pH值为7.2的环境条件下,在添加少量蔗糖的聚合物培养基中培养7d,聚合物黏度可降低92.1%,并使其分子量从18×10⁶降至0.5×10⁶,聚合物总量也有所减少。核磁共振实验分析表明,聚合物酰胺基团含量由74.6%降至60.8%,羧酸基团则明显增加。将其同表面活性剂代谢菌T11复配时,彼此不存在拮抗作用,并且能和地层水配伍。物理模型实验表明,在聚合物驱后使用该复合菌种,可使采收率提高5.4%;在微生物驱后再采用三元复合驱,采收率总量可提高9.7%。在非均质岩心中,菌种能更多地动员低渗透地层中的残余油,并清理出滞留聚合物。

Capability and mechanism of microbe action in polymer-flooding reservoir

A kind of polymer degrading microbe JHW-31 was selected from Daqing Oilfield. The microbe was inoculated and cultured in the culture medium confected with polymer and a little sucrose for 7 days under the condition of pH 7.2 and temperature 45℃. The viscosity reduction rate of the polymer reached 92.1%，and the molecular weight of the polymer decreased from 18×10⁶ to 0.5×10⁶. The gross of the polymer decreased a little bit. Nuclear magnetic resonance test result indicated that the content of the amide group in the polymer decreased from 74.6% to 60.8%, while the carboxylic acid group increased obviously. This kind of microbe could be confected with the surfactant microbe T11 and was compatible with the stratum water. The physical simulation indicated that the oil recovery increased by 5.4% when the microbe was used after polymer flooding. If the ASP flooding was used after microbe flooding, oil recovery could increase by 9.7%. In the heterogeneous core, this microbe can mobilize more remaining oil in the low-permeability zone and clean out the resorted polymer.