Hydrocarbon enrichment patterns and exploration targets in the Paleogene Liushagang Formation, Wushi Sag, Beibuwan Basin, China

WU Keqiang, HU Desheng, YOU Junjun, MAN Xiao, XU Shouli

doi:10.11698/PED.20250482

0 20260308 - 20260308

DOI: https://doi.org/10.11698/PED.20250482

Hydrocarbon enrichment patterns and exploration targets in the Paleogene Liushagang Formation, Wushi Sag, Beibuwan Basin, China

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Zhanjiang Branch of CNOOC (China) Co., Ltd., Zhanjiang 524057, China

Received date: 2025-09-01

Revised date: 2026-03-20

Online published: 2026-03-27

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Abstract

The Paleogene Liushagang Formation in the Wushi Sag of the Beibuwan Basin is characterized by dispersed hydrocarbon distribution, small-scale residual exploration targets and large burial depth. Based on data from drilling, laboratory experiments, and geophysic analysis, this study systematically investigates the hydrocarbon accumulation conditions and enrichment patterns in the Liushagang Formation. The key findings are obtained in five aspects. First, the structural evolution of the sag involved three distinct stages: early faulting, mid-stage detachment deformation and late adjustment, governed by an “extension-detachment-strike-slip” composite fault system that controlled basin subsidence, depocenter migration and sedimentary environment evolution. Second, three principal source rock intervals in the Eocene Liushagang Formation, concentrated in the southern East Sub-sag under the control of the No. 7 Fault Zone, are characterized by considerable thickness and high quality, with the oil shale in the lower part of the second member of Liushagang Formation (lower Liu-2 Member) being the most prolific, providing a robust resource foundation in the sag. Third, four reservoir-seal assemblages are identified, corresponding to three hydrocarbon migration systems: direct source-reservoir contact, fault-sandbody coupling, and fault-structural ridge-sandbody stepwise composite networks. Fourth, three accumulation models are established: “young source-old reservoir” with lateral stepwise migration, “self-sourced and self-stored” intra-source enrichment, and “lower source-upper reservoir” with vertical migration. Fifth, exploration priorities are further delineated, highlighting deep fault-block traps in the central zone, intrasag lithologic traps, and bedrock buried-hill targets with direct source-reservoir connectivity, all demonstrating significant resource potential.

Key words： hydrocarbon enrichment pattern; accumulation model; exploration direction; Paleogene Liushagang Formation; Wushi Sag; Beibuwan Basin

Cite this article

WU Keqiang, HU Desheng, YOU Junjun, MAN Xiao, XU Shouli . Hydrocarbon enrichment patterns and exploration targets in the Paleogene Liushagang Formation, Wushi Sag, Beibuwan Basin, China[J]. Petroleum Exploration and Development, 0 : 20260308 -20260308 . DOI: 10.11698/PED.20250482

References

[1] 邓勇, 胡德胜, 朱继田, 等. 北部湾盆地油气成藏规律与勘探新领域、新类型、资源潜力[J]. 石油学报, 2024, 45(1): 202-225.
DENG Yong, HU Desheng, ZHU Jitian, et al.Hydrocarbon accumulation regularities, new fields and new types of exploration, and resource potentials in Beibuwan Basin[J]. Acta Petrolei Sinica, 2024, 45(1): 202-225.
[2] 胡林, 金秋月, 杨希冰, 等. 乌石凹陷东区构造演化特征及中浅层油气富集规律研究[J]. 特种油气藏, 2020, 27(5): 68-73.
HU Lin, JIN Qiuyue, YANG Xibing, et al.Structure evolution and middle-shallow hydrocarbon enrichment patters in the eastern Wushi Sag[J]. Special Oil & Gas Reservoirs, 2020, 27(5): 68-73.
[3] 徐长贵, 吴克强, 裴健翔, 等. 超深水超浅层天然气富集机理与成藏模式: 以琼东南盆地陵水36-1气田为例[J]. 石油勘探与开发, 2025, 52(1): 44-56.
XU Changgui, WU Keqiang, PEI Jianxiang, et al.Enrichment mechanisms and accumulation model of ultra-deep water and ultra-shallow gas: A case study of Lingshui 36-1 gas field in Qiongdongnan Basin, South China Sea[J]. Petroleum Exploration and Development, 2025, 52(1): 44-56.
[4] 高阳, 刘惠民. 渤海湾盆地济阳坳陷古近系全油气系统特征与成藏模式[J]. 石油勘探与开发, 2025, 52(3): 551-562.
GAO Yang, LIU Huimin.Geological characteristics and hydrocarbon accumulation model of the whole petroleum system in Paleogene of Jiyang Depression, Bohai Bay Basin, China[J]. Petroleum Exploration and Development, 2025, 52(3): 551-562.
[5] 范彩伟, 谢兵, 徐昉昊, 等. 北部湾盆地涠西南凹陷负反转构造对石炭系潜山优质储层的控制作用[J]. 石油勘探与开发, 2025, 52(5): 997-1006.
FAN Caiwei, XIE Bing, XU Fanghao, et al.Control of negative inversion structures on high-quality Carboniferous buried hill reservoirs in the Weixinan Sag, Beibu Gulf Basin, China[J]. Petroleum Exploration and Development, 2025, 52(5): 997-1006.
[6] 胡林, 杨希冰, 徐雪丰, 等. 南海北部湾盆地乌石凹陷成藏主控因素与成藏模式[J]. 海洋地质与第四纪地质, 2016, 36(2): 121-127.
HU Lin, YANG Xibing, XU Xuefeng, et al.Main controlling factors and accumulation models of hydrocarbon in Wushi Sag, Beibu Gulf Basin, South China Sea[J]. Marine Geology & Quaternary Geology, 2016, 36(2): 121-127.
[7] 杨希冰, 胡林, 金秋月. 乌石凹陷中—东区油气来源及成藏时间分析[J]. 东北石油大学学报, 2016, 40(5): 9-17.
YANG Xibing, HU Lin, JIN Qiuyue.Analysis of hydrocarbon origin and its accumulation time in the middle and east zone of Wushi Sag[J]. Journal of Northeast Petroleum University, 2016, 40(5): 9-17.
[8] 杨希冰. 南海北部北部湾盆地油气藏形成条件[J]. 中国石油勘探, 2016, 21(4): 85-92.
YANG Xibing.Hydrocarbon accumulation conditions in Beibu-gulf Basin, northern South China Sea[J]. China Petroleum Exploration, 2016, 21(4): 85-92.
[9] 满勇, 范彩伟, 薛红涛, 等. 北部湾盆地乌石凹陷断裂系统演化特征及其对油气成藏的控制作用[J]. 东北石油大学学报, 2022, 46(4): 37-47.
MAN Yong, FAN Caiwei, XUE Hongtao, et al.Evolutionary characteristics of fault system and its control effect on hydrocarbon accumulation in Wushi Sag, Beibuwan Basin[J]. Journal of Northeast Petroleum University, 2022, 46(4): 37-47.
[10] 吴孔友, 刘煜磊, 胡德胜, 等. 北部湾盆地乌石凹陷东区断裂类型及其形成演化[J]. 地质力学学报, 2021, 27(1): 52-62.
WU Kongyou, LIU Yulei, HU Desheng, et al.Types and evolution of faults in the east area of the Wushi Sag, Beibuwan Basin[J]. Journal of Geomechanics, 2021, 27(1): 52-62.
[11] 钟广见, 易海, 林珍. 粤东中生界油气地质特征[J]. 南海地质研究, 2008(1): 46-53.
ZHONG Guangjian, YI Hai, LIN Zhen.Petroleum geological characteristic of Mesozoic in eastern Guangdong province, China[J]. Gresearch of Eological South China Sea, 2008(1): 46-53.
[12] 胡望水, 吴婵, 梁建设, 等. 北部湾盆地构造迁移特征及对油气成藏的影响[J]. 石油与天然气地质, 2011, 32(6): 920-927.
HU Wangshui, WU Chan, LIANG Jianshe, et al.Tectonic transport characteristics and their influences on hydrocarbon accumulation in Beibuwan Basin[J]. Oil & Gas Geology, 2011, 32(6): 920-927.
[13] 张岳桥, 董树文. 晚中生代东亚多板块汇聚与大陆构造体系的发展[J]. 地质力学学报, 2019, 25(5): 613-641.
ZHANG Yueqiao, DONG Shuwen.East Asia multi-plate convergence in Late Mesozoic and the development of continental tectonic systems[J]. Journal of Geomechanics, 2019, 25(5): 613-641.
[14] 李三忠, 曹现志, 王光增, 等. 太平洋板块中—新生代构造演化及板块重建[J]. 地质力学学报, 2019, 25(5): 642-677.
LI Sanzhong, CAO Xianzhi, WANG Guangzeng, et al.Meso-Cenozoic tectonic evolution and plate reconstruction of the pacific plate[J]. Journal of Geomechanics, 2019, 25(5): 642-677.
[15] HU C, REN J Y, TONG D J, et al.Multiphase growth and basin control of main faults on northern sub-basin, Beibuwan Basin, northwestern South China sea[J]. Marine and Petroleum Geology, 2024, 169: 107052.
[16] LI Y, WANG H, ZHANG G T, et al.Depositional evolution and models for a deep-lacustrine gravity flow system in a half-graben rifted sag, Beibuwan Basin, South China Sea[J]. Geologica Acta, 2022, 20: 1-18.
[17] 李才, 杨希冰, 范彩伟, 等. 北部湾盆地演化及局部构造成因机制研究[J]. 地质学报, 2018, 92(10): 2028-2039.
LI Cai, YANG Xibing, FAN Caiwei, et al.On the evolution process of the Beibu gulf basin and forming mechanism of local structures[J]. Acta Geologica Sinica, 2018, 92(10): 2028-2039.
[18] 王征, 佟殿君, 高铭恒, 等. 北部湾盆地乌石凹陷东洼伸展滑脱构造发育演化模式及其油气地质意义[J]. 地球科学, 2022, 47(7): 2509-2520.
WANG Zheng, TONG Dianjun, GAO Mingheng, et al.Development of extensional decollement faults and its petroleum implications in Wushi east subsag, Beibuwan Basin[J]. Earth Science, 2022, 47(7): 2509-2520.
[19] WANG Z, REN J Y, HU C, et al. Differential extrusion of Indochina-South China block and its interplay with slab-pull tectonics: Evidence for end-Oligocene Basin inversion in the Beibuwan Basin[J]. Tectonics, 2025, 44(1): e2024TC008326.
[20] 满晓, 胡德胜, 范彩伟, 等. 乌石凹陷“背形负花构造” 成因及油气富集规律差异性研究[J]. 中国海上油气, 2021, 33(5): 32-39.
MAN Xiao, HU Desheng, FAN Caiwei, et al.Study on the origin of “antiform negative flower structure” and the difference of oil and gas enrichment law in Wushi Sag[J]. China Offshore Oil and Gas, 2021, 33(5): 32-39.
[21] 徐雪丰, 胡林, 满勇, 等. 乌石凹陷东区走向斜坡控砂模式与勘探实践[J]. 西南石油大学学报 (自然科学版), 2017, 39(3): 77-84.
XU Xuefeng, HU Lin, MAN Yong, et al.Sand control model and exploration practice for East Wushi Sag strike slope[J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2017, 39(3): 77-84.
[22] 罗威, 张道军, 刘新宇, 等. 乌石凹陷南部陡坡带流二段大型储集体发育条件及特征[J]. 沉积学报, 2018, 36(1): 154-165.
LUO Wei, ZHANG Daojun, LIU Xinyu, et al.Large reservoirs development condition and characteristics of the second member of Liushagang Formation in the southern steep slope zone, Wushi Depression[J]. Acta Sedimentologica Sinica, 2018, 36(1): 154-165.
[23] 杨希冰, 谌志远, 满勇, 等. 乌石东区流沙港组地层断裂控砂机制[J]. 断块油气田, 2017, 24(3): 342-345.
YANG Xibing, SHEN Zhiyuan, MAN Yong, et al.Sand distribution mechanism of Liushagang Formation in eastern Wushi area[J]. Fault-Block Oil and Gas Field, 2017, 24(3): 342-345.
[24] 董方, 吴孔友, 崔立杰, 等. 北部湾盆地乌石凹陷东区构造转换带识别及其特征[J]. 石油地球物理勘探, 2021, 56(5): 1180-1189.
DONG Fang, WU Kongyou, CUI Lijie, et al.Identification and characteristics of structural transfer zones in the east area of Wushi Sag, Beibuwan Basin[J]. Oil Geophysical Prospecting, 2021, 56(5): 1180-1189.
[25] 尹嘉, 魏琳, 侯读杰, 等. 南海北部湾盆地乌石凹陷原油地球化学特征与油源对比[J]. 地球科学, 2023, 48(11): 4135-4152.
YIN Jia, WEI Lin, HOU Dujie, et al.Geochemical characteristics and oil-source rock correlation of crude oil in Wushi Sag, Beibuwan Basin, South China Sea[J]. Earth Science, 2023, 48(11): 4135-4152.
[26] 李福来, 吕琳, 马文宽, 等. 乌石凹陷流沙港组烃源岩地球化学特征[J]. 中国石油大学学报 (自然科学版), 2021, 45(1): 31-40.
LI Fulai, LYU Lin, MA Wenkuan, et al.Geochemical characteristics of source rocks in Liushagang Formation of Wushi Sag[J]. Journal of China University of Petroleum (Edition of Natural Science), 2021, 45(1): 31-40.
[27] HUANG B J, ZHU W L, TIAN H, et al.Characterization of Eocene lacustrine source rocks and their oils in the Beibuwan Basin, offshore South China Sea[J]. AAPG Bulletin, 2017, 101(9): 1395-1423.
[28] 李友川, 兰蕾, 王柯, 等. 北部湾盆地流沙港组湖相烃源岩的差异[J]. 石油学报, 2019, 40(12): 1451-1459.
LI Youchuan, LAN Lei, WANG Ke, et al.Differences in lacustrine source rocks of Liushagang Formation in the Beibuwan Basin[J]. Acta Petrolei Sinica, 2019, 40(12): 1451-1459.
[29] HUANG B J, TIAN H, WILKINS R W T, et al. Geochemical characteristics, palaeoenvironment and formation model of Eocene organic-rich shales in the Beibuwan Basin, South China Sea[J]. Marine and Petroleum Geology, 2013, 48: 77-89.
[30] 范彩伟, 周刚, 唐蓿, 等. 北部湾盆地乌石油田成藏条件及勘探开发关键技术[J]. 石油学报, 2025, 46(2): 466-482.
FAN Caiwei, ZHOU Gang, TANG Xu, et al.Accumulation conditions and key technologies for exploration and development of Wushi Oilfield in Beibuwan Basin[J]. Acta Petrolei Sinica, 2025, 46(2): 466-482.

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