川西坳陷须家河组须三段烃源岩地化特征

Geochemical Characteristics of Source Rock in Xujiahe 3 Member, Western Sichuan Depression

为了系统地评价川西坳陷须家河组须三段烃源岩,对其发育特征进行了分析,对其有机碳含量、氯仿沥青"A"含量、干酪根元素组成、干酪根显微组分以及镜质体反射率等地球化学参数进行了测试。结果表明,川西坳陷须三段烃源岩分布范围广,厚度大;烃源岩有机质丰度高;有机质类型为Ⅱ2型与Ⅲ型,但Ⅲ型有机质(腐殖型)占绝对优势;有机质主要处于成熟至高成熟阶段。川西坳陷须三段烃源岩发育,品质较好,以中等—好烃源岩为主,具有较强的生气潜力。

For the source rock of Xujiahe 3 Member, western Sichuan depression, its development features were analyzed. In addition, some geochemical parameters were tested, containing organic-carbon content, chloroform bitumen'A'content, kerogen composition and maceral, and vitrinite reflection ratio(RO). Results show that(1) the source rock is characterized by wide distribution and large thickness;(2) its organic-matter abundance is high;(3) the organic-matter types include II2and III, however, the latter(also called humic type) has far superior position; and(4) the organic matter is usually in mature to high-mature stages. In general, the source rock in this member with better quality, which is dominated by medium or good ones, is well developed and has a stronger gasgenerating potential.