地质科技通报2025，Vol.44Issue(5)：106-122,17.DOI:10.19509/j.cnki.dzkq.tb20250049
陆相断陷湖盆深层页岩沉积特征及勘探潜力评价:以板桥凹陷沙三段为例
Sedimentary characteristics and exploration potential evaluation of deep shale in continental rift lake:A case study of the Third Member of the Shahejie Formation in the Banqiao Sag
摘要
Abstract
[Objective]Currently,exploration and development of shale hydrocarbon primarily focus on mid-shallow marine and lacustrine shales.However,research on the sedimentary characteristics of deep lacustrine shales in rift basins is scarce,so their exploration potential is unclear.Consequently,this study holds significant practical implications and can provide valuable insights into the exploration and development of deep lacustrine shales in the rift basins.A typical deep shale series developed in the distal part of the fan front and the deep lake area of the Third Member of the Shahejie Formation in the Banqiao Sag,which is a continental rift basin.This study aims to identify the sedimentary characteristics of the deep lacustrine shale in the Third Member of the Shahejie Formation in the Banqiao Sag,to demarcate the vertical sweet spots of shale oil and gas,and to comprehensively evaluate the exploration potential of the deep lacustrine shale.[Method]Based on data from core analysis,well logging,and various analytical tests,by employing techniques such as geological statistics,sedimentary facies and organic geochemical analysis,rock thin section observation,X-ray diffraction of whole-rock minerals,micro-CT scanning,and geophysical prediction,the macroscopic sedimentary features,rock fabric types,bedding structures,as well as microscopic structures and compositional characteristics of the shale were analyzed to explore its material basis for hydrocarbon generation and the conditions for hydrocarbon formation.[Result]Macroscopically,the shale series of the Third Member of the Shahejie Formation can be classified into three types:mixed sedimentation type,intercalated type,and interbedded type.The mixed sedimentation type and intercalated type have a wide distribution range.The rocks mainly consist of black and dark gray mudstones,which are the dominant rock fabric types.Microscopically,extremely thin-laminated and thin-laminated mud shales exhibit relatively high organic carbon contents and are the dominant lamination types.The analysis of diagenetic evolution indicates that below a depth of 3 350 m,there are zones where interlayer water is rapidly expelled and zones where interlayer water is expelled rapidly along with organic matter.The resulting abnormal high pressure is conducive to the preservation of microscopic pores.[Conclusion]Comprehensive research shows that the main part of the shale series in the Third Member of the Shahejie Formation in the Banqiao Sag has reached the mature to highly mature stage.It possesses favorable conditions for the enrichment and accumulation of oil and gas on a large scale.Moreover,it is indicated that the C2 and C6 sweet spots are the main zones of oil and gas enrichment,providing theoretical support for the exploration and evaluation of shale oil and gas.The impact of tectonic activities on the generation and accumulation of shale oil and gas has not been adequately considered.Research on shale formations is still in its early stages,and numerous issues remain that require in-depth investigation.It is essential not only to elucidate the material basis for the occurrence of shale oil and gas but also to identify the key factors influencing their production.Therefore,future efforts should focus on achieving technical breakthroughs in the field of integrated geological and engineering approaches.关键词
陆相断陷湖盆/板桥凹陷/沙河街组/页岩油气/岩石类型/孔隙结构/有机碳含量/勘探潜力Key words
continental rift lake/Banqiao Sag/Shahejie Formation/shale gas and oil/lithofacies type/pore structure/organic carbon content/exploration potential分类
天文与地球科学引用本文复制引用
曹强,赵军,周可佳,王昌丽,孟立娜,崔宇,董越崎,李宏军,尹玲玲,时永僖..陆相断陷湖盆深层页岩沉积特征及勘探潜力评价:以板桥凹陷沙三段为例[J].地质科技通报,2025,44(5):106-122,17.基金项目
湖北省自然科学基金地质创新发展联合基金项目(2024AFD396) （2024AFD396）
中国石油天然气股份有限公司大港油田分公司项目(DGYT-2024-JS-1383) （DGYT-2024-JS-1383）
