烃源岩中烷基二苯并噻吩组成及其地球化学意义

RELATIVE ABUNDANCE OF ALKYL DIBENZOTHIOPHENE IN THE SOURCE ROCKS AND THEIR GEOCHEMICAL SIGNIFICANCES

对一个海相地层的实际剖面进行了研究，发现烃源岩芳烃馏分中烷基二苯并噻吩和烷基苯并萘噻吩的相对丰度与碳酸盐矿物含量间有良好的正相关性．不同岩性中含硫芳烃相对丰度的变化顺序是：碳酸盐岩＞泥灰岩＞泥质岩．在深度剖面上，二苯并噻吩（ＤＢＴ）与甲基二苯并噻吩（ＭＤＢＴ）呈消长关系。４－ＭＤＢＴ和２＋３－ＭＤＢＴ的相对丰度随埋深增加而增加．１－ＭＤＢＴ则随之下降，４－ＭＤＢＴ／１－ＭＤＢＴ值和２＋３－ＭＤＢＴ／１－ＭＤＢＴ值能较好地反映有机质的热演化程度．

The study of a profile through marine formation shows that there is a positive corelation between carbonate content and the relative abundance of alkyl dibenzothiophene and alkyl benzonaphothiophene in the source rocks. The contents of dibenzothiophene and methyl dibenzothiophene have an opposite trend with increasing burial depth. It means that methyl dibenzothiophene could be formed through the alkylation of dibenzothiophene during the thermal evolution. The relative abundances of 4-methyl dibenzothiophene and 2+3-methyl ditenzothiophene increased with the burial depth. The ratios of 4-methyl dibenzothiophene to 1-methyl dibenzothiophene and 2+3-methyl dibenzothiophene to l-methyl dibenzothiophene may be used as the maturity indicators to reflect the maturity of organic matter in the source rocks.