贾培蒙,杜家元,陈维涛,等. 断陷盆地边缘洼陷优质烃源岩形成机制—以珠江口盆地惠州26洼东北次洼为例[J]. 海洋地质与第四纪地质,2022,42(3): 140-148. doi: 10.16562/j.cnki.0256-1492.2022021701
引用本文: 贾培蒙,杜家元,陈维涛,等. 断陷盆地边缘洼陷优质烃源岩形成机制—以珠江口盆地惠州26洼东北次洼为例[J]. 海洋地质与第四纪地质,2022,42(3): 140-148. doi: 10.16562/j.cnki.0256-1492.2022021701
JIA Peimeng,DU Jiayuan,CHEN Weitao,et al. Formation mechanism of high quality source rocks in the depression of faulted basin margin: A case study of Huizhou 26 northeast subsag, Pearl River Mouth Basin[J]. Marine Geology & Quaternary Geology,2022,42(3):140-148. doi: 10.16562/j.cnki.0256-1492.2022021701
Citation: JIA Peimeng,DU Jiayuan,CHEN Weitao,et al. Formation mechanism of high quality source rocks in the depression of faulted basin margin: A case study of Huizhou 26 northeast subsag, Pearl River Mouth Basin[J]. Marine Geology & Quaternary Geology,2022,42(3):140-148. doi: 10.16562/j.cnki.0256-1492.2022021701

断陷盆地边缘洼陷优质烃源岩形成机制—以珠江口盆地惠州26洼东北次洼为例

Formation mechanism of high quality source rocks in the depression of faulted basin margin: A case study of Huizhou 26 northeast subsag, Pearl River Mouth Basin

  • 摘要: 珠江口盆地珠一坳陷惠州26洼为典型的断陷盆地,是已证实的富生烃洼陷。以往对优质烃源岩的研究主要集中在其盆地内部,而对湖盆边缘次洼的烃源岩特征及形成机制鲜有报道。为弥补以往研究的空白,选择惠州26洼东北次洼作为研究区,根据最新的地震、地化和元素分析等资料,对该次洼的烃源岩地化特征和形成机制进行详细研究。结果表明,该次洼文四段发育优质烃源岩,有机质丰度高,含量均值为4.59%,可达“好—很好”烃源岩标准,有机质类型为Ⅰ—Ⅱ1型,以生油为主。文四段沉积时期,惠州26洼东北次洼强烈断陷,形成“洼缘深盆”,且陆源碎屑物质输入量少,为烃源岩发育提供有利的沉积环境,同期火山活动提供了丰富的无机营养物质,形成咸水环境,引起浮游生物勃发,促进有机质的规模形成和保存。综合分析认为,惠州26洼东北次洼文四段优质烃源岩的发现,将优质烃源岩分布范围扩大至湖盆边缘,为该洼陷未来勘探发现奠定生烃基础,对其他地区断陷盆地边缘洼陷评价和勘探潜力分析具有重要的借鉴意义。

     

    Abstract: Huizhou 26 Sag, Zhuyi Depression, Pearl River Mouth Basin, is a typical faulted basin, which is proved to be rich in hydrocarbon generation. The research on high-quality source rocks is mainly concentrated in the interior of the basin, but there is little research on the characteristics and formation mechanism of source rocks in subsag at the margin of sag. Based on the latest data of earthquake, geochemistry and elements analysis, the geochemical characteristics and formation mechanism of source rocks in the Northeast subsag of Huizhou 26 sag are studied in detail. High quality source rocks were developed in WC4 Formation, with high abundance of organic matter, with an average content of 4.59%, which can reach the standard of “good-very good” source rocks, and organic matter type is Ⅰ-Ⅱ1, mainly oil-type source rock. During the sedimentary period of the WC4 Formation, Huizhou 26 northeast subsag was strongly faulted, forming a “Deep basin in sag edge”, Less terrigenous debris input, which provided a favorable sedimentary environment for the development of source rocks. Volcanic activities in the same period provided rich inorganic nutrients, form a salt water environment, cause the plankton bloom, and promote the large-scale formation and preservation of organic matter. The comprehensive analysis shows that the discovery of high-quality source rocks in WC4 Formation, Huizhou 26 northeast subsag, expands the distribution of high-quality source rocks to the edge of the sag, which lays a hydrocarbon generation foundation for the future exploration and discovery of the sag, and has important reference significance for the evaluation and exploration potential analysis of subsag at the edge of fault basin in other areas.

     

/

返回文章
返回