摘要
粘土矿物在埋藏成岩过程中的重要变化是膨胀型粘土逐渐减少(如蒙脱石),伊利石、绿泥石结晶度逐渐增加(半高宽减小)。通过对具有代表性的常6—1—1井粘土矿物X衍射分析,系统研究了伊利石10A峰、绿泥石7A峰的半高宽、A/H值(背影峰面积/峰高)与镜质体反射率R_0以及有机质热变指数LOM的对应关系。研究结果表明伊利石(特别经乙二醇处理过)的10A峰半高度及A/H值可以估算有机质成熟与否;可以作为预测源岩生油门限以及油气保存阶段的指标。
the most important changes in clay minerals with increasing depth of burial are the regular reduction of expandable layers (eg. smectite) and the gradual increase in crys-tallinity of illite and chlorite (decrease of the half-width value with depth). The study area is
represented by Chang 6-1-1 well clay mineralogy, the half-width of the 10 A illite, and 7A chlorite peaks, and the A/H value (area under peak/peak height) are systematically related to thermal maturity which is represented by vitrinite R0?the mean values of the level of organic metamorphism(LOM). The results of this suggest that, in the absence of vitrinite, the
values of the the half-width of the 10A peak and A/H value of the illite (especially glycolate) may be used to quantitatively estimate the levels of thermal maturity and consequently as indicators to differentiate source rock above and below the oil generation threshold and to approximate the hydrocarbon generation and preservation stages of potential source rocks.
