In place of EOR at Daqing Oilfield, ASP flooding has seen a leap forward in six aspects:

• The development and formula optimization of chemical agents in the strong-base, weak-base and base-free systems;
  
  
• Physicochemical seepage and other basic theories;
  
  
• Fine description of remaining oil;
  
  
• Simulation optimization of compound flooding process;
  
  
• R&D of produced fluid treatment technologies and scale prevention measures;
  
  
• Field experiments, which will secure the field's sustainable 40Mt/a oil productivity in the long term.

Our capacity in strong-base flooding systems has been continuously upgraded to produce 50,000 metric tons of heavy alkylbenzene sulfonate-based surfactant a year. A weak-base flooding system has been developed and used in field experiments. Formula optimization for ASP flooding field experiments: The flooding efficiency can be much more enhanced with less cost thanks to the optimization of multi-slug compound flooding systems, high-concentration polymer applications, and alternative injection of polymer and alkali-polymer. Scale-prevention lifting process technologies: A series of scale prevention and removal agents suitable for different scale compositions can extend the pump maintenance period in scaling wells to around 200 days, from the 40 days at the preliminary stage of scale formation. Ground treatment of produced fluid: The produced fluid from ASP flooding can be effectively treated using our newly developed demulsifier with both water clarifying and demulsifying functions. In addition, multiple matching technologies for the treatment of produced water from ASP flooding have been developed, such as minor-flocculation-based filtering of suspending sludge, microorganism treatment and water stabilizers.

Daqing's industrial test of strong-base ASP flooding has delivered remarkable results. In the central well block of Duandong experimental zone in block North-1, recovery has increased 18.35% at the current stage and is expected to rise by 20.6%. In the central well block of the experimental zone in block South-5, recovery has increased 13.55% at the current stage and is expected to rise by 17.4%.