关键词: 渗吸, 压敏性, 压力波动, 周期注水, 低渗透

Abstract: Mechanisms of cyclic water injection are analyzed by combining rock pressure sensitivity experiment and imbibition experiment in view of the characteristics of much remaining oil in the matrixes of fractured low permeability reservoir.Imbibition experiment of different permeability cores and different pressure drops，pressure sensitivity experiment of permeability are studied and compared.The results show that，imbibition recovery ratio firstly increases and then decreases with the increasing of permeability，permeability loss of core is mainly in the early stage of effective pressure increase，influence of pressure drop degree and speed on imbibition recovery ratio takes on the trend of firstly decreasing then increasing，pressure sensitivity is mainly at the smaller pressure drop degree，and the pressure difference caused by pressure fluctuation plays roles mainly at the bigger pressure drop degree and speed in the process of cyclic water injection.

Key words: imbibition, pressure sensitivity, pressure fluctuation, cyclic water injection, low permeability