海洋地质前沿2025，Vol.41Issue(12)：16-28,13.DOI:10.16028/j.1009-2722.2024.249
复式箕状断陷两类烃源岩发育模式
Development models of two types of source rocks in the composite half-graben basin:a case study of Yueguifeng Formation in the Lishui Sag
摘要
Abstract
To clarify the development model of source rocks in the composite half-graben basins,we studied the Yueguifeng Formation in the Lishui Sag.The tectonic background and sedimentary facies were analyzed,and rep-resentative wells were selected from different tectonic units and sedimentary facies zones.The source rocks in or-ganic petrology and geochemistry were compared.Results show that the enrichment of organic matter in the source rocks of Yueguifeng Formation was directly related to the amount of organic matter input and preservation conditions.Two enrichment models were developed,namely,the prodelta mixed input type and the mid-deep la-custrine in-situ preservation type.The enrichment degree of the two types of source rocks in half-graben basins was different in each sub-sag due mainly to the variation of the sedimentary"source-to-sink"systems around dif-ferent sub-sags.In the mixed input type,the degree of organic matter enrichment under weakly oxidizing environ-ments depended on the amount of terrestrial organic matter in the delta,and the dominant kerogen type was Ⅱ2-Ⅲ.This type of source rock is generally distributed in the western Lishui Sag in prodelta facies.In the in-situ pre-servation type,the accumulation of organic matter in a mildly reduction environment was controlled by the growth of local aquatic organisms and preservation conditions.The kerogen type is mainly type Ⅱ2,and the source rock of this type is distributed in the central area of the sag under the control of the growth of syn-rift faults.The west-ern part of the Lishui Sag faced a vast Zhejiang-Fujian uplift to the west,with braided river delta development and large sediment injection,resulting in a small scale of development of type Ⅱ2 source rocks,while the eastern part of Lishui Sag was in-between the Lingfeng Low uplift and Yandang uplift,receiving small-scale input from point-sourced rocks,thus the development scale of this type of source rock is relatively large.关键词
复式箕状断陷/烃源岩/有机质富集模式/月桂峰组/丽水凹陷Key words
composite half-graben basin/source rock/enrichment model of organic matter/Yueguifeng Forma-tion/Lishui Sag分类
海洋科学引用本文复制引用
王宁,覃军,常文琪,董哲,朱虹浩..复式箕状断陷两类烃源岩发育模式[J].海洋地质前沿,2025,41(12):16-28,13.基金项目
中海石油(中国)有限公司"十四五"重大项目"近海重点潜在富烃洼陷评价技术"(KJGG2022-0301) （中国）
