Status and trend of chemical flooding and layered injection technology in Daqing Oilfield

The process of separate injection in chemical flooding is a key method of enhancing oil recovery and guaranteeing sustainable development of oilfield at the high water-cut stage. In Daqing Oilfield, a relatively sophisticated process of polymer injection has been formed according to oil layer types and the technical needs of oil layers at different development stages, and good development results have been achieved. Currently, the technology of chemical flooding dominated by whole process integrated separate injection and dual adjustment of the injection volume and molecular weight in separate layers in the same well have been realized. The downhole string run in one trip meets the requirements of separate injection in 2-7 layers in blank water flooding, chemical flooding and subsequent water flooding. The test process is compatible with water flooding. The operations of fishing, sealing test, and flow measurement and adjustment are electronically controlled. With expansion of chemical flooding, the workload of separate injection wells has been increased, and the limit in capabilities of testing and adjustment has been reached. In order to solve problems such as rapid decrease of success rate of separate injection, short test and adjustment cycle, and low permeability and thinner oil layers with thinner interlayer, it is proposed to integrate automatic monitoring and remote control to realize intelligent monitoring and adjustment of separate injection in chemical flooding. The layered injection technology with small layer spacing and fine layer division has been developed, which provides reference for high-quality and efficient development of oilfield under chemical flooding.