Abstract: The osmosical hydration of montmorillonite has been considered to be one of the most important factors of oil reservoir damages and bit balling. The effects of temperature, inogranic salts (NaCl, KCl, CaCl₂ ) and additive CMC (they are often applied to drilling muds) on the micro structure of montmorillonite were studied. The detection methods of the small angle X-ray diffusion, the micro angle X-ray diffusion and of the Pons' statistic model and fractal theory were used, the results showed that the particle's thickness had increased and developed into 80 crystal sheets from a few crystal sheets of the original. At the same time,the interior order of particle aggregates had also increased.This had made the montmorillonite suspension passing from a gel state to an hydrated solid.The high temperature brought about the particles becoming irreversiblely smaller in the direction vertical to the crystal sheet.

Key words: montmorillonite, microstructure, drilling fluid, temperature, inorganic salt

摘要： 透水化蒙脱土一直被认为是钻井泥包和油层损坏的主要原因之一.利用了小角X散射、微小角X散射检测方法和Pons统计模型以及分形学理论.研究了温度(200℃)和泥浆中常用的无机盐(NaCl、KCl、CaCl₂)以及处理剂CMC对蒙脱土微观结构的影响.钠蒙脱土悬浮液在承受K⁺和Ca²⁺交换以及高温(200℃)作用以后其结构发生变化:在KCl和CaCl₂交换的情况下,蒙脱土颗粒厚度增大,由原来的几个晶片组合发展到80个晶片组合,同时,颗粒内部组合有序度增加,使蒙脱土悬浮体从一个胶体状态演变到水化固体状态.温度的作用使蒙脱土悬浮体的颗粒在垂直晶片平面方向上产生不可逆分裂而变小.

关键词: 蒙脱石, 微观结构, 钻井液, 温度, 无机盐