There are broad prospects of CO2 flooding for enhancing oil recovery and greenhouse gas storage. In this paper, we re. viewed the development history and brief situation of CO2 flooding at home and abroad, analyzed the development status of CO2 im. miscible flooding and CO2 huff and puff, and summarized the phase state of CO2 flooding, oil displacement mechanism evaluation and optimization design technology of CO2 flooding reservoir engineering. The design focused on improving oil displacement effi. ciency and sweep efficiency, controlling viscosity index and gas breakthrough, achieving miscible or near-miscible flooding, and optimizing well pattern and injection parameters in combination with reservoir characteristics. It was pointed out that CO2 near-mis. cible flooding and increasing sweep volume were the development trends of CO2 flooding. WAG, foam flooding, fracture sealing and local gravity flooding were important means to prevent gas channeling. On the basis of summarizing the current CO2 flooding tech. nology and field experience at home and abroad, the top-level design of combination of CO2 flooding and CO2 geological storage should be done according to different types of reservoir characteristics.
Progress in Exploration Geophysics
enhanced oil recovery
CO2 huff and puff
prevent gas channeling
present situation and development trend