Layered injection technology for chemical flooding of Class-Ⅲ oil reservoirs in the Daqing Oil Fields complex,Songliao Basin,Northeast China

The Class-Ⅲ oil reservoirs of Lasaxing oilfield in the Daqing Oil Fields complex have geological oil reserves of 1.86 billion tonnes,an oil recovery of 39%,with remaining reserves accounting for more than 45%of the total geological reserves of the oilfield.Therefore,they have considerable potential for future oil production.The current layered injection technologies fail to achieve effective control over the low single-layer injection rates since they can only produce low throttle differential pressure under low injection rates(5-20 m^(3)/d).In this study,a symmetrically-structured double-offset-hole injection allocator and a novel throttling component were developed.Their spatial layout was constructed and mechanical parameters were optimized using finite element analysis,which allows for expanding the flow rate range at low injection rates.According to experimental results,the throttle differential pressure increased from 0.2 MPa to 0.8 MPa at an injection rate of 5 m^(3)/d,and the range of the single-layer flow rates expanded from 20-70 m^(3)/d to 5-70 m3/d.The field test results show that the effective production of oil layers with medium and low permeability was achieved and that the ratio of producing oil layer thickness to the total reservoir thickness increased by 9.7%on average.Therefore,this study provides valuable technical support for the effective chemical-flooding-based development of Class-Ⅲ oil reservoirs.

Redevelopment of Daqing Oil Field distributed earthquake disaster reduction system skeleton

Through investigation on the international development trend of earthquake disaster reduction system(EDRS)researches,a well finished Daqing Oilfield EDRS is introduced.Based on the PC System,redevelopment of the EDRS skeleton is well discussed,including the technical skeleton,function composition,structures of software and hardware,redevelopment languages,database,and remote linking and calling of analysis modules.Meanwhile,it is pointed out that extending and utilizing the function of remote sensing information on the basis of the current distributed EDRS skeleton will become another study direction of EDRS.

IMPACT OF OIL FIELD EXPLOITATION ON ECO-ENVIRONMENT OF THE DAQING LAKES

The Daqing lakes are located in the region with sub-humid continent al monsoon climate. Through historical comparison of the environment before and after oil field exploitation in the area, the paper analyses the impact of oil f ield exploitation on the eco-environment of the lakes, including the impact of diversion works, drainage works, exploitation and utilization of groundwater, dr opped crude oil and petrochemical wastewater on the lakes water body. The analys is shows that oil field exploitation caused serious pollution to soil in the lak es area and deterioration of the eco-environment. The impact became more eviden t with passage of time, and the intensity varied with areas, getting more seriou s from west to east, which meant that the eastern part of the lakes were influen ced much more seriously by the human activities. To improve the eco-environment of the Daqing lakes and make them sustainable utilization, the effective protec tion measures should be taken.