摘要
通常在定量分析孔隙度、渗透率等物性参数变化规律时,往往假设迂曲度不发生变化。分析了在地层压力下降的情况下砂岩气藏岩石迂曲度的变化规律,以期对常规岩石渗透率变化规律定量研究结果进行修正。根据岩石孔隙结构毛管束简化模型对应的Kozney方程,推导建立了岩石比迂曲度变化理论关系式。结合模拟有效压力增加岩石变形实验,通过将地面实验数据转换为地层条件下孔隙度和渗透率变化数据,考虑储层岩石所承受初始有效压力,实例计算了地层压力下降岩石迂曲度变化规律。实例气藏6个岩心的计算结果表明,随着地层压力下降,岩石迂曲度逐渐增大,且岩石迂曲度的增幅已超过了可以忽略的程度,说明通常假设岩石迂曲度为常数是有局限的。因此,在研究砂岩气藏地层压力下降对岩石渗透率影响时,需要考虑岩石迂曲度的变化。
During variation rules of porosity ,permeability and other tatively,we suppose the tortuosity has no change.The variation rules formation pressure decreased in sandstone gas reservoir so as to physical properties were analyzed quanti of the rock tortuosity were analyzed when modify the quantitative results of the varia- tion rule of the general rock permeability.According to the Kozney equation based on the bundle of capillary tubes pack of rock pore structure ,theoretical equation of specific rock tortuosity was established.The data of porosity and permeability by the experiment in the surface was transformed to that in the formation condition after the simulated experiment of effective stress increase.The variation rule of rock tortuosity when the formation pressure decreases was calculated in the actual gas reservoir based on considering the initial rock effective stress.The calculated results of six cores indicate that rock tortuosity increased gradually with the for- mation pressure decreased,and it is so large that can＇t be neglected.That is to say,the traditional method of ignoring the rock tortuosity change is limited.So,when we research the effect of formation pressure decrease on rock permeability in the sandstone gas reservoir,we should consider the variation of rock tortuosity.
出处
《中外能源》
CAS
2010年第4期39-41,共3页
Sino-Global Energy
关键词
砂岩气藏
孔隙度
渗透率
迂曲度
比迂曲度
sandstone gas reservoir
porosity
permeability
tortuosity
specific tortuosity
