大庆石油地质与开发2026，Vol.45Issue(1)：54-62,9.DOI:10.19597/J.ISSN.1000-3754.202409038
天文轨道周期下威远地区五峰组—龙马溪组页岩有机质富集的驱动机制
Driving mechanism of organic matter enrichment of Wufeng Formation-Longmaxi Formation shale in Weiyuan area under astronomical orbital cycle
摘要
Abstract
The development and enrichment of organic matter are the material basis for the formation of"sweet spots/intervals"of shale oil and gas.In order to reveal the driving mechanism of shale organic matter enrichment in Wei-yuan area of Sichuan Basin,based on the analysis of cyclostratigraphy,biostratigraphy and geochemistry,compre-hensive research on sedimentary environment evolution and organic matter enrichment pattern of shale in Wufeng Formation-Longmaxi Formation under the control of astronomical orbital cycle changes is conducted through high-frequency cyclostratigraphic division of Wufeng Formation-Longmaxi Formation in typical well WD2.The results show that,typical astronomical periodic signals are identified in Wufeng Formation-Longmaxi Formation of Weiyu-an area,indicating that the strata preserves good astronomical orbital periodic records.A depth-time model is estab-lished by band-pass filtering of 405 ka long eccentricity,and approximately 6 long slope cycles are obtained by fil-tering the long slope cycle(1.2 Ma),which has good corresponding relationship with the restored global sea-level changes during this period.In early and middle Rhuddanian stage(LM1-3 graptolite zones),global warming led to a rise in sea level,increased nutrients,mass reproduction of palaeontology,enhanced productivity,decreased ter-restrial clastic input,low deposition rate and the anaerobic environment,which was conductive to the enrichment of organic matter.In contrast,in middle and late Rhuddanian stage(LM4-5 graptolite zones),the sea level gradual-ly declined,terrestrial clastic input increased,productivity decreased and the whole w(TOC)decreased.It is con-cluded that the change of astronomical orbital cycle has control on the global sea-level change,influencing the sedi-mentary environment evolution of Wufeng Formation-Longmaxi Formation in Weiyuan area as well as the enrich-ment of organic matter.LM1-LM3 graptolite zones are the high-quality shale intervals in studied area.关键词
旋回地层学/页岩/有机质富集/沉积环境/威远地区/五峰组—龙马溪组Key words
cyclostratigraphy/shale/organic matter enrichment/sedimentary environment/Weiyuan area/Wufeng Formation-Longmaxi Formation分类
能源科技引用本文复制引用
陈诚,管全中,陈鑫,李冲达,叶玥豪,吴娟,焦堃,梁浩然,完颜泽..天文轨道周期下威远地区五峰组—龙马溪组页岩有机质富集的驱动机制[J].大庆石油地质与开发,2026,45(1):54-62,9.基金项目
国家自然科学基金项目"深层页岩有机质力学稳定性及对有机质孔隙的保存机理"(42202192) （42202192）
四川省自然科学基金项目"富氦页岩气藏氦气封闭机理研究——以四川盆地龙马溪组为例"(2024NSFSC0811). （2024NSFSC0811）
