南阳凹陷核三1段烃源岩地球化学特征

Geochemical Characteristics of Source Rocks of H31Formation in the Nanyang Depression

综合应用钻井、地震等地质资料,以大量烃源岩样品地球化学分析为基础,从暗色泥岩分布、沉积环境、有机质丰度、类型、成熟度,烃源岩生烃史以及生物标志化合物等方面对南阳凹陷核三1段烃源岩地球化学特征进行了研究.结果表明研究区暗色泥岩发育,烃源岩有机质类型以I-II1型为主,有机质丰度高,整体为中等-好级别烃源岩;有效烃源岩现今大多处于低成熟-成熟演化阶段.单井生烃史模拟结果表明,核三1段底部烃源岩于核一段沉积早期开始生烃,于18 Ma左右开始进入大量生烃阶段,具有较高的生烃潜力.生物标志化合物分析结果表明,核三1段烃源岩沉积于半咸水-咸水,强还原-还原湖相沉积环境.

Based on the drill and seismic date and the organic geochemical analysis data of the source rocks,the comprehensive research of the source rocks of H31 Formation in the Nanyang Depression was conducted from the aspects of the distribution of mud stone,sedimentary environment,geochemical characteristics of source rocks, history of the hydrocarbon generation and characteristics of the biomarkers,etc. The result indicated that the studied area had the characteristics of good dark mudstone,high abundance of organic matter,I-II1 organic matter type, low maturity or maturity. The result of the history simulation of hydrocarbon generation indicated that the H31 source rocks began generation from the mid period of H1 Formation,even reaching the peak stage of hydrocarbon generation from 18 Ma. The biomarkers analysis showed that the source rock of H31 deposited in brackish water-salt water and highly reduced-reduced environment.