天然气工业2025，Vol.45Issue(4)：48-59,12.DOI:10.3787/j.issn.1000-0976.2025.04.004
四川盆地震旦纪德阳—安岳裂陷钙质空间模型及其演化
Calcareous space model of Sinian Deyang-Anyue rift in the Sichuan Basin and its evolution
摘要
Abstract
The Deyang-Anyue rift in the Sichuan Basin controls the distribution of high-quality source rocks,high-quality reservoirs,and the distribution pattern of the gas reservoirs of Sinian Dengying Formation.Studying the evolution of this rift is of great significance to petroleum geology.In this paper,the contact relationship between the Sinian and the Cambrian is investigated by observing,sampling and analyzing field outcrops and drilling cores,combined with geophysical characteristics.Then,a new concept of calcareous space model is proposed by analyzing the sedimentary environmental evolution and geochemical characteristics of the Dengying Formation in the Deyang-Anyue rift and its periphery.Finally,the evolution of the calcareous space in the Deyang-Anyue rift and its control on the deposition of the carbonate rocks in the rift are reconstructed.The following results are obtained.First,the Sinian Dengying Formation in the Deyang-Anyue rift is in a conformable contact relationship with the Cambrian Maidiping Formation.The Maidiping Formation is generally developed and the Dengying Formation is not obviously absent in the Deyang-Anyue rift and its periphery.Second,the sedimentary environment of the Dengying Formation in the Deyang-Anyue rift evolves from shallow water to deep water,with the shallow water environment showing positive carbon isotopes of carbonate rocks and the deep water environment showing negative values.The Dengying Formation exhibits the evolution of positive to negative carbon isotopes from bottom to top,and at the top of the Dengying Formation develops a condensed section whose isotopes are dominantly negative.These characteristics are closer to those in the deep-water basin facies of the Dengying Formation,but do not appear outside the rift,which indicates that the sedimentary environments of the Dengying Formation inside and outside the rift are significantly different.Third,below the sea level develops a calcareous space that controls the deposition rate of carbonate rocks and varies with the rise and fall of the sea level.Calcareous space is the key to controlling the deposition rate of creatures and carbonate rocks,and it can be subdivided into organic-chemical type and inorganic-chemical type,both of which are greatly different in the deposition rate.Fourth,the sedimentary environment of the Dengying Formation within the Deyang-Anyue rift evolves from the shallow-water platform facies in the early stage to the deep-water slope facies in the late stage,and its calcareous space evolves from the organic-chemical type in the early stage to the inorganic-chemical type in the late stage,resulting in a sharp decrease of the deposition rate of carbonate rocks and the development of the condensed section within the rift,which is the fundamental reason for the large-scale thinning of the Dengying Formation within the rift.In conclusion,the variation of calcareous space is the fundamental reason for the evolution and final formation of the Deyang-Anyue rift.Moreover,the study based on the calcareous space model can reconstruct the formation process of the Deyang-Anyue rift more rationally,equate the size of the calcareous space to the thickness of the rock layer,and provide a new research thinking and geological model for the qualitative and semi-quantitative research on the temporal and spatial evolution of sedimentary cycles and sedimentary environments.关键词
四川盆地/德阳—安岳裂陷/碳酸盐岩/海平面/钙质饱和面/钙质空间/凝缩层Key words
Sichuan Basin/Deyang-Anyue rift/Carbonate rock/Sea level/Calcareous saturated surface/Calcareous space/Condensed section分类
石油、天然气工程引用本文复制引用
王文之,陈曦,杨跃明,文龙,罗冰,张本健,阎泽昊,袁倩,唐志娟,谭杰..四川盆地震旦纪德阳—安岳裂陷钙质空间模型及其演化[J].天然气工业,2025,45(4):48-59,12.基金项目
中国石油天然气股份有限公司科技项目"碳酸盐岩油气富集规律及有利区带研究"(编号:2023ZZ16YJ01). （编号:2023ZZ16YJ01）
