蒙皂石粘土矿物不正常转化的研究——以准噶尔盆地为例

利用岩石薄片和X射线衍射资料，分析了准噶尔盆地腹部地区蒙皂石粘土矿物的不正常转化。该区庄1井、成1井和董1井在超压段内粘土矿物转化出现异常现象，蒙皂石以及伊／蒙混层的相对含量随深度增加有所增加，而伊利石的相对含量随深度增加有所减少。结合前人的研究资料，讨论了超压对粘土矿物转化的影响。超压能增加蒙皂石层间水的稳定性，阻碍超压仓与外界流体和离子的交换，使伊利石含量有所减少。同时，火山岩屑物质的大量存在可能导致在晚成岩阶段伊／蒙混层含量较高，蒙皂石的含量也有所增加。

A study on abnormal transformation of smectite clay minerals——taking Junggar Basin as an example

The abnormal transformation of smectite clay minerals in central Junggar Basin is analyzed according to the petrographic thin section and X - ray diffraction data. The abnormal phenomena about transformation of clay minerals appear in wells of Zhuangl, Cheng1 and Dong1 under overpressure: the relative content of smectite and illite/smectite interlayer increases, but the relative content of illite decreases along with the increment of depth. Based on the data collected from former researchers, the influence of overpressure on transformation of the clay minerals is discussed. Overpressure can strengthen stability of interlayer water of smectite, and inhibit exchanges between overpressure compartments and outside fluid and ions, which result in the decrease of illite content. At the same time, volcanic cinder may lead to high content of illite/smectite interlayer at later diagenetic stage, and the content of smectite increases correspondingly.