Sequence stratigraphic framework and sedimentary system of the Lower Cretaceous Kedeni Formation in Eastern Depression of Doseo Basin,Chad
CHEN Hongkui1, ZHU Xiaomin1, XIAO Kunye2, DU Yebo2, YUAN Zhiyun2, ZHANG Xinshun2, WANG Xiaoxue3
1 College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China; 2 Research Institute of Petroleum Exploration and Development,Petrochina,Beijing 100083,China; 3 Tarim Institute of Geophysical Exploration of Bureau of Geophysical Prospecting Inc,CNPC,Xinjiang Korla 841000,China
Abstract：A significant breakthrough has been made in hydrocarbon exploration in the Kedeni Formation of the Doseo Basin in the Central African Rift System. However,the stratigraphy and sedimentary infill of this dominant formation are still unclear,which has become a key constraint for the next step of hydrocarbon exploration. In this study,the Kedeni Formation in the Eastern Depression of Doseo Basin is taken as the research object. Based on the theory of seismic stratigraphy and sedimentology,combined with the core,logging and seismic data,the sequence stratigraphic framework and sedimentary system distribution of Kedeni Formation are clarified. The research results demonstrate that the Kedeni Formation exhibits three identifiable sequence interfaces,dividing into two third-order sequences(SQⅠ and SQⅡ),in response to two ‘transgressive-regressive’ cycles. The sediments of Kedeni Formation mainly came from four directions,and six types of sedimentary facies were developed. Distribution of sedimentary facies was characterized by east-west differentiation and features of vertical inheritance. Normal delta were distributed in the southeastern gentle slope zone and the central low uplift zone,whereas the braided river delta were primarily distributed in the long axis direction of the northeast and the southern steep slope zone. The fan delta and the nearshore subaqueous fan developed in the downthrown side of the boundary fault in the northern steep slope zone. The sublacustrine fan were mainly distributed in the deep lake area of the western sag. Vertically,the framework sandstone scale of the SQⅠ was larger than that of the SQⅡ,and in each third-order sequence,the delta-subaqueous fan was more developed in the lower unit composed of a lowstand system tract and a transgressive system tract. The sequence and sedimentary evolution of the Kedeni Formation were primarily controlled by factors such as the structural activity of major faults,differential sediment supply from the south to the north,and shifts in climate from semi-arid to humid conditions. Under the guidance of sequence-sedimentary model,it is considered that the small-scale fan delta front-nearshore subaqueous fan sandstone in the northern steep-slope zone,the large-scale normal delta front and braided river delta front sandstone in the south and northeast,and the sublacustrine fan sandstone in the deep lake area of the western sag can be regarded as favorable exploration targets within the region.
CHEN Hongkui,ZHU Xiaomin,XIAO Kunye et al. Sequence stratigraphic framework and sedimentary system of the Lower Cretaceous Kedeni Formation in Eastern Depression of Doseo Basin,Chad[J]. JOPC, 2024, 26(4): 796-815.
[1] 陈全红,赵红岩,李全,张科,阳怀忠,陈经覃,李克永,郭家铭,饶勇. 2021. 乍得Doseo盆地白垩纪沉积充填演化及对油气成藏的控制作用. 沉积学报, 41(3): 919-931. [Chen Q H,Zhao H Y,Li Q,Zhang K,Yang H Z,Chen J T,Li K Y,Guo J M,Rao Y.2021. Cretaceous sedimentary filling evolution and its control on hydrocarbon accumulation in Doseo Basin,Chad. Acta Sedimentologica Sinica, 41(3): 919-931] [2] 窦立荣,潘校华,田作基,肖坤叶,张志伟. 2006. 苏丹裂谷盆地油气藏的形成与分布: 兼与中国东部裂谷盆地对比分析. 石油勘探与开发, 33(3): 255-261. [Dou L R,Pan X H,Tian Z J,Xiao K Y,Zhang Z W.2006. Hydrocarbon formation and distribution of rift basins in Sudan: a comparative analysis of them with rift basins in East China. Petroleum Exploration and Development, 33(3): 255-261] [3] 窦立荣,肖坤叶,胡勇,宋红日,程顶胜,杜业波. 2011. 乍得Bongor盆地石油地质特征及成藏模式. 石油学报, 32(3): 379-386. [Dou L R,Xiao K Y,Hu Y,Song H R,Cheng D S,Du Y B.2011. Petroleum geology and a model of hydrocarbon accumulations in the Bongor Basin,the Republic of Chad. Acta Petrolei Sinica, 32(3): 379-386] [4] 窦立荣,肖坤叶,杜业波,王利,张新顺,程顶胜,胡瑛. 2022. 乍得Doseo走滑反转盆地油气成藏特征和勘探发现. 石油勘探与开发, 49(2): 215-223. [Dou L R,Xiao K Y,Du Y B,Wang L,Zhang X S,Cheng D S,Hu Y.2022. Exploration discovery and hydrocarbon accumulation characteristics of the Doseo strike-slip and inverted basin,Chad. Petroleum Exploration and Development, 49(2): 215-223] [5] 高华华,杜业波,王林,高思敏,胡杰,白建峰,马洪,王玉华,张新顺,刘浩. 2023. 乍得Doseo盆地东部构造特征、成因机制与盆地演化. 石油勘探与开发, 50(5): 1003-1015. [Gao H H,Du Y B,Wang L,Gao S M,Hu J,Bai J F,Ma H,Wang Y H,Zhang X S,Liu H.2023. Tectonic features,genetic mechanisms and basin evolution of the eastern Doseo Basin,Chad. Petroleum Exploration and Development, 50(5): 1003-1015] [6] 何文渊,王利,汪望泉,肖坤叶,杜业波,吴亚东,马明福,潘春孚. 2023. 中非走滑裂谷盆地群石油地质特征与勘探方向. 中国石油勘探, 28(3): 90-99. [He W Y,Wang L,Wang W Q,Xiao K Y,Du Y B,Wu Y D,Ma M F,Pan C F.2023. Petroleum geological characteristics and exploration orientation in strike-slip rift basin group in central Africa. China Petroleum Exploration, 28(3): 90-99] [7] 孔令武,张树林,韩文明,赵红岩,赵佳奇,喻英梅. 2019. 走滑—拉分盆地构造特征及盆地成因模式探讨: 以中非多赛奥盆地为例. 高校地质学报, 25(5): 722-729. [Kong L W,Zhang S L,Han W M,Zhao H Y,Zhao J Q,Yu Y M.2019. Discussion on the structural features and formation mechanism of strike-slip pull-apart basin: a case study in the Doseo Basin,Central Africa. Geological Journal of China Universities, 25(5): 722-729] [8] 林孝先. 2011. 陆源碎屑岩盆地综合物源分析. 成都理工大学硕士学位论文. [Lin X X.2011. A synthetic thought of provenance analysis in the terrigenous clastic rock basin. Masteral dissertation of Chengdu University of Technology] [9] 刘为付. 2016. 乍得Doseo盆地白垩系层序地层与沉积体系. 中南大学学报(自然科学版), 47(6): 1981-1989. [Liu W F.2016. Cretaceous sequence stratigraphy and depositional system in Doseo Basin,Chad. Journal of Central South University(Science and Technology), 47(6): 1981-1989] [10] 吕彩丽,赵阳. 2018. 中非裂谷盆地构造演化差异性与构造动力学机制. 西南石油大学学报(自然科学版), 40(6): 23-34. [LV C L,Zhao Y.2018. Differences in tectonic evolution and mechanisms of tectonic dynamics of rift basins in Central Africa. Journal of Southwest Petroleum University(Science & Technology Edition), 40(6): 23-34] [11] 饶勇,程涛,杨松岭,赵红岩,李全,陈全红. 2023. 中非Doseo盆地油气地质条件及成藏控制因素分析. 地质与勘探, 59(5): 1117-1127. [Rao Y,Cheng T,Yang S L,Zhao H Y,Li Q,Chen Q H.2023. Hydrocarbon accumulation characteristics and controlling factors of the Doseo Basin in Central Africa. Geology and Exploration, 59(5): 1117-1127] [12] 童晓光,窦立荣,田作基,潘校华,朱向东. 2004. 苏丹穆格莱特盆地的地质模式和成藏模式. 石油学报, 25(1): 19-24. [Tong X G,Dou L R,Tian Z J,Pan X H,Zhu X D.2004. Geological mode and hydrocarbon accumulation mode in Muglad passive rift basin of Sudan. Acta Petrolei Sinica, 25(1): 19-24] [13] 徐杰,姜在兴. 2019. 碎屑岩物源研究进展与展望. 古地理学报, 21(3): 379-396. [Xu J,Jiang Z X.2019. Provenance analysis of clastic rocks: current research status and prospect. Journal of Palaeogeography(Chinese Edition), 21(3): 379-396] [14] 杨棵,朱筱敏,杨怀宇,朱世发,董艳蕾,金磊,申婷婷,叶蕾. 2022. 古物源体系多方法表征: 以渤海湾盆地沾化渤南洼陷沙四下亚段为例. 沉积学报, 40(6): 1542-1560. [Yang K,Zhu X M,Yang H Y,Zhu S F,Dong Y L,Jin L,Shen T T,Ye L.2022. Multi method characterization of a paleo-provenance system: a case study from the lower 4th member of the Shahejie Formation from the Bonan Sag in Zhanhua Depression,Bohai Bay Basin. Acta Sedimentologica Sinica, 40(6): 1542-1560] [15] 张光亚,余朝华,陈忠民,张荻萩,温志新,黄彤飞,王彦奇,刘小兵,马锋,赵健. 2018. 非洲地区盆地演化与油气分布. 地学前缘, 25(2): 1-14. [Zhang G Y,Yu Z H,Chen Z M,Zhan D Q,Wen Z X,Huang T F,Wang Y Q,Liu X B,Ma F,Zhao J.2018. Tectonic evolution and hydrocarbon distribution in African basins. Earth Science Frontiers, 25(2): 1-14] [16] 张光亚,黄彤飞,刘计国,余朝华,赵岩,刘爱香,客伟利,王彦奇. 2019. 非洲Muglad多旋回陆内被动裂谷盆地演化及其控油气作用. 岩石学报, 35(4): 1194-1212. [Zhang G Y,Huang T F,Liu J G,Yu Z H,Zhao Y,Liu A X,Ke W L,Wang Y Q.2019. Multi-cycle evolution of the intracontinental passive rift basins and its controlling on accumulation of oil & gas: taking Muglad Basin in Africa as an example. Acta Petrologica Sinica, 35(4): 1194-1212] [17] 张光亚,余朝华,黄彤飞,程顶胜,陈忠民,陈曦,刘红,宋成鹏. 2020. 非洲地区裂谷盆地类型及油气成藏特征. 中国石油勘探, 25(4): 43-51. [Zhang G Y,Yu Z H,Huang T F,Chen D S,Chen Z M,Chen X,Liu H,Sun C P.2020. Types and hydrocarbon accumulation characteristics of rift basins in Africa. China Petroleum Exploration, 25(4): 43-51] [18] 张艺琼,何登发,童晓光. 2015. 中非剪切带含油气盆地成因机制与构造类型. 石油学报, 36(10): 1234-1247. [Zhang Y Q,He D F,Tong X G.2015. Genetic mechanisms and tectonic types of petroliferous basins in the Central Africa Shear Zone. Acta Petrolei Sinica, 36(10): 1234-1247] [19] 周小蓉,陈石,张新顺,丁宝通,宋兴国,潘楚琦,彭梓俊. 2023. 南乍得盆地Doseo坳陷背形负花状构造成因分析. 现代地质, 37(5): 1146-1154. [Zhou X R,Chen S,Zhang X S,Ding B T,Song X G,Pan C Q,Peng Z J.2023. Genetic mechanism analysis of antiformal negative flower structure in Doseo Depression,south Chad Basin. Geoscience, 37(5): 1146-1154] [20] 朱筱敏,赵东娜,曾洪流,孙玉,朱如凯,黄薇,朱世发. 2013. 松辽盆地齐家地区青山口组浅水三角洲沉积特征及其地震沉积学响应. 沉积学报, 31(5): 889-897. [Zhu X M,Zhao D N,Zeng H L,Sun Y,Zhu R K,Huang W,Zhu S F.2013. Sedimentary characteristics and seismic sedimentologic responses of shallow-water delta of Qingshankou Formation in Qijia area,Songliao Basin. Acta Sedimentologica Sinica, 31(5): 889-897] [21] 朱筱敏. 2020. 沉积岩石学(第五版).北京: 石油工业出版社,314-430. [Zhu X M.2020. Sedimentary Petrology(5th ed). Beijing: Petroleum Industry Press,314-430] [22] 朱筱敏,王华,朱红涛,邵龙义,纪友亮. 2023. 陆相层序地层学研究进展及发展关注. 石油学报, 44(8): 1382-1398. [Zhu X M,Wang H,Zhu H T,Shao L Y,Ji Y L.2023. Research progress and development focuses of continental sequence stratigraphy. Acta Petrolei Sinica, 44(8): 1382-1398] [23] Dou L R,Zhang X S,Xiao K Y,Xi D P,Du Y B,Wang L,Hu J,Hu Y,Zheng Q Y.2023. Early Cretaceous(Aptian to Albian)vegetation and climate change in Central Africa: novel palynological evidence from the Doseo Basin.Geological Journal: 1-27. [24] Fairhead J D.2020. Chapter 20-Regional tectonics and basin formation: the role of potential field studies-an application to the MesozoicWest and Central African Rift System. In: Scarsellin,Adam J,Chiarella D, et al.(eds). Regional Geology and Tectonics Volume 1: Principles of Geologic Analysis(2nd ed). Amsterdam: Elsevier,541-556. [25] Genik G J.1993. Petroleum geology of Cretaceous-Tertiary rift basins in Niger,Chad,and Central African Republic.AAPG Bulletin, 77(8): 1405-1434. [26] Guiraud R,Bosworth W,Thierry J,Delplanque A.2005. Phanerozoic geological evolution of Northern and Central Africa: an overview. Journal of African Earth Sciences, 43(1-3): 83-143. [27] Patterson P E,Skelly R L,Jones C R.2012. Climatic controls on depositional setting and alluvial architecture,Doba Basin,Chad. In Baganz O W,Bartov Y,Bohacs K,Nummedal D(eds).Lacustrine sandstone reservoirs and hydrocarbon systems.AAPG Memoir, 95: 265-298. [28] Wu D,Zhu X M,Su Y D,Li Y T,Li Z,Zhou Y Y,Zhang M Y.2015. Tectono-sequence stratigraphic analysis of the lower cretaceous Abu Gabra formation in the fula sub-basin,Muglad Basin,southern Sudan. Marine and Petroleum Geology, 67: 286-306. [29] Yassin M A,Hariri M M,Abdullatif O M,Abdullatif O M,Makkawi M,Bertotti G,Kaminski M A.2018. Sedimentologic and reservoir characteristics under a tectono-sequence stratigraphic framework: a case study from the Early Cretaceous,upper Abu Gabra sandstones,Sufyan Sub-basin,Muglad Basin,Sudan. Journal of African Earth Sciences, 142: 22-43. [30] Zhang X S,Xiao K Y,Wang J C,Wang L,Du Y B,Hu J,Hu Y,Wang Y F.2021. Organic geochemical characteristics of Lower Cretaceous source rocks and crude oils in Doseo Depression of central African rift system. Journal of African Earth Sciences, 175: 104118. [31] Zhang X S,Dou L R,Nie Z Q,Xiao K Y,Wang L,Du Y B,Chen S,Wang L,Zhou X R.2023. Role of two-stage strike slip faulting in the tectonic evolution of the Doseo depression in the central Africa rift system.Frontiers in Earth Science, 11: 1087217.
