镇泾油田低渗透油藏岩石渗透率应力敏感性研究

Evaluation of the Stress-Sensitivity for Permeability in Zhenjing Low-Permeability Sandstone Rock

对镇泾油田低渗透油藏岩石进行了渗透率应力敏感性实验研究,并对其进行了应力敏感性评价。实验是在一定围压下,通过降低和增加内压的方式完成的,共进行了2个围压下的变内压实验。实验结果和应力敏感性评价结果表明,镇泾油田低渗透油藏不存在渗透率强应力敏感性,在原始地层压力条件下,衰竭式开发对地层的渗透率几乎没有影响,注水开发对地层的渗透率会有一定程度的改善。同时,通过对有效应力定律方程的研究,得出渗透率有效应力系数为常数且值很小,这从机理上解释了镇泾油田低渗透油藏岩石的渗透率对应力不敏感的原因。

This paper discusses the stress-sensitivity evaluation of low-permeability sandstone with the completion of the laboratory study on the stress-sensitivity for permeability of Zhenjing low-permeability oil reservoir. The experiments included two cycles,with each running at constant-confining-stress by increasing and decreasing pore pressure. The results of experiment study and stress-sensitivity evaluation indicate that at initial reservoir pressure,depletion type of development exerts no effect on the reservoir permeability,but flood development can improve the permeability to some degree. Meanwhile the study of the equation of effective stress law shows that the effective stress coefficient obtained for the permeability is constant and very small. This may explain the fact that the permeability of Zhenjing oil field is non-sensitive to the stress from mechanism.