纯化油田注入水中细菌堵塞岩心实验研究

Experimental Study on Core Plugging Caused by Bacteria in Injection Water for Flooding Chunhua Reservoir

岩心流动实验装置全系统灭菌;地层水和注入水过滤、灭菌;储层岩心洗油、饱和地层水;用注入水接种培养,制备低、中、高含菌量的驱替用水,其中TGB、SRB、IB菌总菌数分别为1.06×102、1.49×103、1.29×104个/mL。用低、中、高含菌量的3种含菌水驱替岩心,注入量分别为70、70、64PV,岩心对地层水的渗透率分别由9.06×10-3、15.93×10-3、11.84×10-3μm2变为10.16×10-3、1.45×10-3、0.72×10-3μm2,对岩心渗透率的伤害分别为-12.1%、90.9%、93.9%,岩心流出液中总菌数分别为0、4.0×100、4.1×101个/mL。讨论了注水过程中细菌在岩心孔隙中的截留和岩心堵塞。认为纯化油田砂岩油藏注入水中各种细菌的总数应控制在1×102个/mL以下。图3表4参2。

The full laboratory core flow installation used is properly sterilized; the formation water (FW) and the injection water (IW) used—filtrated and sterilized; the reservoir core—processed, deoiled and saturated with the FW. The bacteria containing IW with total population of bacteria TGB, SRB, and IB being of 1.06×10~2, 1.49×10~3, and 1.29×10~4 cell/mL is prepared by the way of seeding and cultivation in IW. Flooding the cores with the IW of low, medium and high bacteria population in total volume injected 70, 70, and 64 PV results in change in permeability of the cores to FW from original values 9.06×10^(-3), 15.93×10^(-3), and 11.84×10^(-3) μm^2 to 10.6×10^(-3), 1.45×10^(-3), and 0.72×10^(-3) μm^2, that is, a damage rate observed being of -12.1%, 90.9%, and 93.9%, and the total population of bacteria remainded in the IW flown out of the cores is of 0, 4×10~0, and 4.1×10~1 cell/mL, respectively. The retention of bacteria in core pores and the blockage creation in cores in the course of water injection are discussed. It is suggested that the total population of harmfull bacteria in the IW for flooding sandstone reservoirs in Chunhua oil fields be kept below 1×10~2 cell/mL.