安达凹陷沙河子组烃源岩层序及地化特征浅谈

Brief Talk about Source Rock Sequence in Shahezi Formation of Anda Sag and Its Geochemical Characteristics

安达凹陷沙河子组地层主要发育低水位体系域；水进体系域只在局部发育，范围很小；高水位体系域在全区分布广泛。沙河子组烃源岩以暗色泥岩最为发育，其有机碳平均值为3．88％，热解S1＋S2平均值为1．360mg／g，原始生烃潜力较大；有机质类型以豫型为主；烃源岩Ro范围值为1．71％～2．43％，平均值为2．00％，在凹陷埋藏较浅地区处于高成熟阶段，其它地区Ro均高于2．0％，达到过成熟阶段。安达凹陷从1998年至今累计提交各级别储量，揭示了本区烃源岩较强的生气能力。

Formation in Shahezi Forrmation of Anda sag mainly develops in lowstand systems tract. transgressive system tract only develops in local part with small extent, and highstand system tract widely distributes in the whole zone. Source rock in Shahezi Formation is dominated by dark mudstone with organic carbon average value of 3. 88% and S1 ＋S2 average value of 1. 360mg/g and large original generation hydrocarbon potentiality. Organic matter type is dominated by Ⅲ type, Ro range value of source rock is between 1.74% and 2.43%, and average value is 2.00%. It is in high-maturity stage in lower zone of sag buried, and Ro in other zones is all more than 2.0%, thus up to post-maturity stage. Anda sag cumulatively submits various orders＇ reserves since 1998. which indicates source rock in this zone has stronger generation gas capacity.