Microfractures seen in thin-section can vary in
aperture from several tens of microns to several
millimetres and can be either open, partly
mineralised or completely mineralised (Fig. 13B, C
and D). The commonest minerals in the
microfractures are anhydrite, barite, siderite, dickite,
other clay minerals, quartz and pyrite (Massa et al.,
1972). It can be shown that dickite crystallised first
in the microfractures, while anhydrite is a late-stage
mineral.
局部充填的裂缝在低渗油藏中非常重要。