Abstract: The advancement of EOR methods in tight reservoirs in last ten years was comprehensively reviewed to promote the theoretical understanding. Moreover, the feasibility of these EOR methods was analyzed based on the mechanisms, and the technical issues and problems existing in lab scale and field scale investigations were presented. Finally, the research focus and development direction of tight reservoir EOR were prospected. After many years of exploration, a series of EOR methods, such as gas injection, chemical methods, smart water, solvent methods, and nanofluid, have been preliminarily formed for tight reservoirs. Among EOR methods, CO₂, natural gas and surfactant hold the most promising potential for application. There are wide gaps and even contradictory conclusions between core scale and field scale studies, which makes it impossible to precisely predict the performance. Therefore, the future researches should be focused on the key scientific questions, such as the interactions between injectants, formation fluids and formation, the multiscale seepage behaviors of oil, gas and water in complex fracture systems, and the mass exchange between tight matrix and fracture, to promote the development of EOR techniques in tight reservoir integrating informative technology.

Key words: tight reservoir, enhanced oil recovery, method and theory, research progress, further development