低渗油藏岩石压敏性及其对渗吸的影响

针对裂缝性低渗透油藏基质中大量原油滞留而采不出来的特点，结合岩芯压敏性实验和渗吸实验，分析了该类油藏周期注水过程中的作用机理。进行了不同渗透率岩芯静态渗吸实验、岩芯的渗透率压力敏感性实验、不同压降条件下的渗吸实验，并将三者实验结果进行了比较分析。研究结果表明，渗吸采收率随着岩芯渗透率的增大而先增大后减小；岩芯渗透率损失主要是发生在有效压力增大的初期阶段；降压幅度和降压速度对渗吸采收率的影响趋势是先减小后增大；周期注水过程中，压力波动幅度较小时，岩芯压敏性起主要作用；当压力波动幅度较大时，压力波动产生的内外压差起主要作用。

INFLUENCE OF PRESSURE SENSITIVITY ON IMBIBITION FOR LOW PERMEABILITY RESERVOIR ROCKS

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.