珠一坳陷文昌组烃源岩发育特征及控制因素

Characterization of Source Rock Development in Wenchang Formation of Zhuyi Depression and Its Controlling Factors

针对珠江口盆地珠一坳陷烃源岩发育的主控因素问题,结合油气地球化学方法、层序地层学和沉积学分析方法,对烃源岩发育特征进行分析;同时,基于浮游藻类化石含量、铀钍比、姥植比和米兰科维奇旋回等,对影响优质烃源岩发育的生源条件、氧化还原条件、沉积速率、体系域等控制因素进行综合分析。结果表明:文昌组优质烃源岩发育于湖侵体系域晚期和高位体系域早期;生源条件、氧化还原环境、沉积速率、体系域等因素协同控制优质烃源岩的发育。优质烃源岩的研究将为珠江口盆地储量突破和深水区有利勘探目标发现奠定基础。

In order to determine the key controlling factors of source rock development in the Zhuyi Depression of the Pearl River Mouth Basin,the source rock development was characterized through hydrocarbon geochemistry,sequence stratigraphy and sedimentology analysis. In addition,the biogenesis condition,oxidation- deoxidation environment,deposition rate,system tract and other controlling factors of high- quality source rock development were comprehensively analyzed by considering phytoplankton fossil content,the ratio of uranium- thorium ratio and pristine- phytane ratio,Milankovitch cycles,etc. Result demonstrates that Wenchang source rock was developed in the late lacustrine transgressive system tract and early highstand system tract. The development of high- quality source rock was cooperatively controlled by biogenesis condition,oxidation- deoxidation environment,deposition rate,system tract,etc. High- quality source rock research could lay a foundation forreserve increase of the Pearl River Mouth Basin and further exploration of favorable zones in deep- water area.