关于碳酸盐岩烃源岩有机质丰度恢复的探讨——以华北中、上元古界碳酸盐岩为例

RESTORATION ON ORGANIC MATTER ABUNDANCE OF CARBONATE SOURCE ROCKS: A CASE OF MIDDLE-UPPER PROTERZOIC CARBONATE ROCKS IN NORTH CHINA

不同烃源岩有机质丰度恢复方法的优缺点不同,但不同方法都以干酪根降解生烃理论为前提条件。原始有机质类型、烃产物的H/C值、高成熟烃源岩中间产物是否排出和反应体系的封闭程度是影响有机质丰度恢复系数大小的主要因素。原始有机质类型较好、烃产物H/C值比较低和中间产物液态烃排出较完全时,所求得的恢复系数比相反的情况要大。对华北北部地区中、上元古界海相碳酸盐岩的有机碳恢复结果表明,下马岭组和铁岭组碳酸盐岩具有较高的原始有机碳丰度,高于庄组部分碳酸盐岩也具有较高的原始有机质丰度:3组均为较好的烃源岩。

Different restoring methods of organic matter abundance of source rocks possess inspective advantages and disadvantages. But these methods are all restricted to realm of hydrocarbon-generating theory of kerogen degradation. The initial organic matter type,mean hydrogen/carbon ratio of hydrocarbon products, median expulsion efficiency from high mature source rocks and close extent of reaction system mainly affect restoration factor of organic matter abundance. These restoration coefficients of total organic carbon in different condition all have maximum values. Restoration results with upper-middle Proterzoic carbonate rocks in North China show that Xiamaling group and Tieling group carbonate rocks have relative high initial organic matter abundance, Gaoyuzhuang group partial carbonate rocks have also relative high initial total organic carbon after restoring.