碳酸盐岩白云岩化作用实验地质学研究

摘要

According to the dynamic mechanisms of dissolution and preciptation of carbonate rocks, two modelling approaches for dolomitization were proposed: 1) repeated heating and cooling; 2) convectional circulation. The modelling products were characterized using several different instruments. The results suggested that dolomites could be obtained by both of the two methods. Through thermodynamic analysis and experimental study, the influences of Mg/Ca concentration ratio, sulfate ion and temperature on dolomitization process were discussed. The study suggested that it was hard to obtain dolomite in the lab because of the difficulty in the growth of dolomite germ. Once the germ appeard, the growing speed of dolomite would be faster than that of calcite. This paper explained why no young age dolomite exists in the natural environment and supplied new thoughts on dolomitization research and carbonate reservoir prediction.%根据碳酸盐岩溶解与沉淀动力学机制,设计了反复升降温和对流循环2套白云岩化模拟方法,利用多种手段对反应产物进行表征,结果表明2种实验方案均可得到白云石晶体.结合热力学分析及实验研究,探讨了Mg/Ca原子比值、温度以及硫酸根离子对白云石生成的影响.研究表明,白云石之所以难以在实验室生成,主要是晶牙生长困难,一旦长出晶牙,白云石生长的速度将大于方解石.该文从实验的角度解释了为何自然界没有年轻的白云岩的现象,为白云岩化机理的探讨及白云岩优质储层的预测提供了新思路.