注入水中微生物对特低渗透储层伤害评价及推荐指标

开展注入水中微生物对特低渗透储层伤害规律及推荐指标研究,对特低渗透油田精细注水、效益注水有着重要的指导作用。在注入水中微生物特征分析和特低渗透储层孔喉特征分析的基础上,针对3种级别的特低渗透储层,分别开展了3种微生物硫酸盐还原菌(SRB)、铁细菌(IB)和腐生菌(TGB)的低、中、高3种浓度的27组岩心流动实验。结果表明:微生物的注入浓度、注入量及匹配度(自身形态与储层喉道的匹配程度值)是影响特低渗透储层渗透率损失值的3种主导因素;随着微生物注入浓度、注入量及匹配度的增大,最终渗透率损失值将增大;在3种微生物中,对储层伤害程度呈现硫酸盐还原菌(SRB)腐生菌(TGB)铁细菌(IB)的规律,应以SRB作为微生物指标中重点控制指标。针对特低渗透油藏储层,提出了注入水中微生物控制指标。

EVALUATION AND RECOMMENDED INDEXES FOR THE ULTRA-LOW PERMEABILITY RESERVOIR DAMAGE BY THE MICROBILE IN THE INJECTED WATER

Researches on the damage laws and recommended indicators to the ultra-low permeability reservoir caused by the microbiles in the injected water have important guiding roles for the fine and effective water injection development of this kind of the oilfield.Based on the analyses of the microbial properties in the injected water and the pore throat characteristics of the ultra-low permeability reservoir,three kinds of the microbile (Sulfate reducing bacteria-SRB,iron bacteria-IB and total growth bacteria-TGB) were considered with three different microbial concentrations for twenty-seven core flow experiments with three levels of the ultra-low permeability.The results show that the injection concentration,injection rate and compatibility (The matched degree between the self-configuration and reservoir pore throat) of the microbile are three leading factors that influence the permeability loss value of the ultra-low permeability reservoir;with the rise of the injection concentration,injection rate and compatibility of the microbile,the ultimate permeability loss value will be increased;for the three microbiles stated above,the rule of the damage degree to the reservoir is presented as SRB>TGB＞IB,SRB should be used as the key control index.For the ultra-low permeability reservoir,the microbial controlling indicators in the injected water were recommended.