高阳东, 林鹤鸣, 汪旭东, 刘培, 李振升, 张琴, 熊万林. 幕式裂陷控洼背景下的烃源岩分布及岩浆改造——以珠一坳陷番禺4洼为例[J]. 海洋地质与第四纪地质, 2021, 41(3): 151-160. DOI: 10.16562/j.cnki.0256-1492.2021012501
引用本文: 高阳东, 林鹤鸣, 汪旭东, 刘培, 李振升, 张琴, 熊万林. 幕式裂陷控洼背景下的烃源岩分布及岩浆改造——以珠一坳陷番禺4洼为例[J]. 海洋地质与第四纪地质, 2021, 41(3): 151-160. DOI: 10.16562/j.cnki.0256-1492.2021012501
GAO Yangdong, LIN Heming, WANG Xudong, LIU Pei, LI Zhensheng, ZHANG Qin, XIONG Wanlin. Source rock distribution pattern in an episodic rifting sag and later stage magmatiic reformation: A case from Panyu 4 sag, Zhu I Depression[J]. Marine Geology & Quaternary Geology, 2021, 41(3): 151-160. DOI: 10.16562/j.cnki.0256-1492.2021012501
Citation: GAO Yangdong, LIN Heming, WANG Xudong, LIU Pei, LI Zhensheng, ZHANG Qin, XIONG Wanlin. Source rock distribution pattern in an episodic rifting sag and later stage magmatiic reformation: A case from Panyu 4 sag, Zhu I Depression[J]. Marine Geology & Quaternary Geology, 2021, 41(3): 151-160. DOI: 10.16562/j.cnki.0256-1492.2021012501

幕式裂陷控洼背景下的烃源岩分布及岩浆改造——以珠一坳陷番禺4洼为例

Source rock distribution pattern in an episodic rifting sag and later stage magmatiic reformation: A case from Panyu 4 sag, Zhu I Depression

  • 摘要: 经历裂陷I幕a期强烈裂陷,a期末北部的抬升和岩浆活动,至裂陷I幕b期北洼萎缩、南洼扩大、新形成北西洼,洼陷整体走向从NE-SW转变为NEE-SSW,珠琼运动II幕整体接受抬升剥蚀。在裂陷I幕演化过程中,半深湖-深湖亚相自下而上呈现自 NE向 SW迁移特征。上文昌组烃源岩面积较大,但仅南部厚度较大,本身湖相有机质含量较高;下文昌组半深湖-深湖亚相烃源岩面积相对较小,北部在I幕a期末被剥蚀后厚度仍较大,南部厚度较小,岩浆活动从某种程度上起到了促进下文昌组有机质成熟、加速成烃的作用。上、下文昌组半深湖-深湖亚相烃源岩具有差异分布的特征,下文昌组的生烃强度优于上文昌组。

     

    Abstract: The Panyu 4, a sag in the Zhu Ⅰ Depression with relatively high degree of exploration, is formed by episodic rifting and reformed by later stage magmatism. The distribution pattern of source rocks in the sag is the key issue to current oil and gas exploration. The latest seismic interpretation, together with the comprehensive research of core data, logging data, geochemical data, suggests that the Wenchang Formation in the Panyu 4 sag has a typical two-layer structure. After intensive rifting in the Stage a of the Rifting Episode I, the uplifting and magmatism in the north of the sag caused the shrinkage of the sag N, the expansion of the sag S and the formation of sag NW. The general strike of the Panyu 4 sag changed form NE-SW to NEE- SSW. In the second Rifting Episode, the Zhu-Qiong movement gave rise to the regional uplifting followed by denudation. In the Rifting Episode I, semi-deep lake deposits gradually turned to deep lacustrine facies from bottom to top following the NE-SW direction. The Lower Wenchang Formation has relatively smaller distribution area for semi-deep and deep lacustrine deposits which is the major source rocks currently in exploration. The Upper Wenchang Formation has larger area in terms of source rock distribution. However, thick source rocks only distributed in the south, where is rich in organic matter and lack of magmatism. Although the lower Wenchang Formation was denuded in the north by the end of the Stage a of the Rifting Episode I, the source rock in the north is thicker than that in the south. The magmatism may enhance the maturity of organic matter and promote the hydrocarbon generation in the Lower Wenchang Formation. The semi-deep and deep lacustrine facies source rocks in the Upper and Lower Wenchang Formations are rather different and the hydrocarbon-generating intensity in the Lower Wenchang Formation is higher than that in the Upper.

     

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