微生物采油技术在大庆油田低渗透油藏的应用

APPLICATION OF MEOR TECHNOLOGY IN THE LOW-PERMEABILITY RESERVOIRS OF DAQING OILFIELD

针对大庆外围低渗透油田开发的诸多不利因素，探索适合低渗透油田开发的有效方法。室内研究筛选出一组以短短芽孢杆菌和蜡状芽孢杆菌为主的配伍菌，并利用上述配伍菌在大庆油田低渗透油藏开展了微生物吞吐和微生物驱现场试验。微生物吞吐矿场试验93口井，有效率74．2％，累计增油1．38×10^4t，单井平均增油148t；2注10采微生物驱矿场试验10口井，7口井见效，累计增油1．45×10^4t。2009年10月，开展了9注24采扩大试验，已有15口生产井含水明显下降，产油量上升41．6％。通过对试验井的分析，确定注采关系、层问差异、供液能力是影响微生物吞吐效果的主要因素。微生物驱试验效果表明，沿主河道砂体和裂缝发育方向注采关系完善的油井见效早，增产效果明显。

Aiming at the various unfavorable factors in the development of the low-permeability oilfield in the peripheral zone of Daqing Oilfield, the effective method which is suitable to the development of the low-permeability oilfields is being explored. A group of compatible bacteria, which are mainly composed of the brevibacillus brevis and the bacillus cereus, are screened in the laboratory research. Moreover, the field tests of microbial huff-and-puff and microbial flooding are conducted in the peripheral low-permeability reservoirs of Daqing Oilfield through the ap- plication of the above compatible bacteria. The microbial huff-and-puff field test has been conducted in 93 wells with the effective rate of 74.2% , and the accumulated incremental oil production and the average incremental oil production per well are 1.38 ×10^4 t and 148 t respectively. The field test of microbial flooding with 2 injectors and 10 producers is conducted in 10 wells, and the stimulation effect is obtained in 7 wells with the accumulated incremental oil production of 1.45 × 10^4 t. In October, 2009, the expanding test with 9 injectors and 24 producers is carried out, the water cut of 15 production wells has been decreased obviously, and meanwhile the oil production has been increased by 41.6%. Through the analysis of the pilot wells, it is determined that the injection-production relationship, interlayer difference and liquid supply ability are the main factors that influence the effect of microbial huff-and-puff. The experiment effect of the microbial flooding shows that the stimulation effect of the wells with per- fect injection-production relationships along the direction of main channel sand body and fracture development are obtained relatively early, and meanwhile the stimulation effect is obvious.