The Study On MEOR Feasibility In Chaoyanggou Oilfield

As the reserves of low permeable reservoir are rich in domestic,its development is very important to China's oil industry. However,because of the complex geological conditions and poor PHysical properties, the issue of its effective exploitation has been needing to be resolved. Microbial enhanced oil recovery(MEOR)has special mechanism of oil displacement and displacement characteristics. In-house and field experiments show that MEOR has an enormous potential application in the low-permeability Oilfield.Aiming at the kernel problem for MEOR,this paper founded research method that combined bacterium screening,fermentation and culturing,performance evaluation. Two bacteria (numberedⅠandⅡ) electing crude oil as the sole carbon source was separated from the fluid of Chaoyanggou reservoir. This bacterium was a facultative anaerobe with oil degradation and acid production, and compatible with Chaoyanggou reservoir well. The fermentation conditions determined through experiments: the culture temperature is 35℃,the air flux is 0.2m3/h,and the range of PH value is 7～8. Different carbon sources, inorganic nitrogen sources and mineral elements were used to confect the culture mediums. The best medium formula components were obtained in orthogonal experimental way.In-house oil degradation experiments show that intended bacteria had favorable properties. After fermentation by intended bacteria, the viscosity and freezing point of oil dropped down, low density components increased, and waxy and gel content decreased. Fermentation liquor produced active substances, so oil-water interface tension reduced and the rheological property of oil improved. Flooding simulation results show that the intended bacteria flooding can enhance oil recovery. With the test compatible with Chaoyanggou Oilfield, the micro-handling efficiency was 61.5 percent, on the average the single well increased oil by 71.5 t, the increment of 65 oil wells accumulated by 4649.2t, and it got better oil and economic benefits. This fully proved the feasibility of MEOR in Chaoyanggou oilfield,and also provided a basis for the better MEOR application in the low-permeability Oilfield.