影响泥页岩在清水中膨胀率因素的探讨

Investigation on influencing factors of mud shale expanding rate in fresh water.

通过对各油气田所钻遇泥页岩的实测数据的综合分析 ,讨论了泥页岩中晶态粘土矿物种类和含量、非粘土矿物、阳离子种类、泥页岩的埋深及外界温度与压力等因素对泥页岩在清水中膨胀率的影响。结果表明 :泥页岩中蒙皂石或伊蒙间层含量和伊蒙间层的间层比是影响泥页岩在清水中膨胀率的主要因素 ,泥页岩膨胀率随伊蒙间层的含量和间层比的增加而增大 ,当伊蒙间层从无序间层转变为有序间层 ,间层比降至 4 0 %以下时 ,泥页岩膨胀率显著降低 ;泥页岩中含有石膏、氯化钠、芒硝等无机盐时 ,加剧其吸水膨胀 ;泥页岩在清水中的膨胀率随非晶态粘土矿物含量的增加而增大 ;随着泥页岩埋深的增加 ,其膨胀率下降 ;泥页岩的膨胀率随温度升高而增大 ,随压力增大而下降。

Influencing factors of mud shale expanding rate in fresh water were investigated based on collaborative analysis on real data of mud shale drilling met in oilfields. The factors include type and content of crystalline clay mineral in mud shale, non crystalline clay mineral, non clay mineral, cationic type, buried depth of mud shale, conditional temperature and pressure. The results showed that one of the main influencing factors of mud shale expanding rate in fresh water is the contents of smectite or illite/montmorillonite interlayer and the interlayer ratio. Expanding rate of mud shale increases with increasing of content of smectite or illite/montmorillonite interlayer. However, as disorder interlayer of illite/montmorillonite changes into order interlayer and the interlayer ratio cuts down to 40% below, the expanding rate will decrease remarkably; absorbing water expanding will be strengthened when inorganic salts such as gypsum, sodium chloride and mirabilite exist in mud shale; the expanding rate also increases with increasing of non crystalline clay mineral and decreases with increasing of buried depth of mud shale. Meanwhile, the expanding rate increases with conditional temperature up and decreases with pressure increasing.