Sedimentary facies characteristics and organic matter enrichment mechanism of lower Cambrian Niutitang Formation in South China

Abstract

The purpose of this study was to examine the sedimentary facies characteristics of lower Cambrian Niutitang Formation (∈₁n) in South China, to reveal the mechanism of organic matter enrichment, and to guide exploration of shale gas. Macro investigation and experimental analyses were used to assess the lithology in detail, total organic matter mass fraction w(TOC), mineral composition, and trace element characteristics of ∈₁n. The influencing factors of organic matter enrichment were discussed extensively, and a sedimentary facies mode was suggested. In the early stage of ∈₁n, the locations of Well E’yangye 1, Well Ciye 1, Well Changye 1, and Well Anye 1 respectively develop, platform inner sag, outer shelf, Jiangnan slope belt, and South China detention basin. In the late stage of ∈₁n, the sedimentary facies evolve with decreasing sea level. The study area presents a complete three-step basin in the Early Cambrian. In the early stage of ∈₁n, the first step is the Yangtze carbonate platform, the second step is the outer shelf and slope, and the third step is the deep-water basin. From the Yangtze carbonate platform to the deep-water basin, w(TOC) and the mass fraction of quartz gradually increase, the mass fraction of carbonate mineral decreases, and the mass fraction of clay mineral is higher in the second step. The sea level fluctuation results in a higher w(TOC) vertically in the lower ∈₁n shale, and the paleogeographic (provenance) conditions lead to better horizontal development of organic matter in the outer shelf, slope and detention basin. Trace elements are abundant in the lower ∈₁n, and w(TOC) is correlated positively with many trace elements. In the outer shelf, slope, and adjacent areas, hydrothermal activity and upwelling current bring nutrient-rich material and promote organic matter enrichment under a strong reducing condition. Deep-shelf, slope and deep-water basin are the best facies for the formation and preservation of organic matter, especially deep-water basin facies. It remains necessary to strengthen the exploration of shale gas in the deep-water basin of ∈₁n in central Hunan, China.

Keywords

Niutitang formation (∈₁n) / organic matter / sedimentary facies / enrichment mechanism / hydrothermal activity / upwelling current / exploration target

References

[1] ZouC-N, DongD-Z, WangY-M, LiX-J, HuangJ-L, WangS-F, GuanQ-Z, ZhangC-C, WangH-Y, LiuH-L, BaiW-H, LiangF, LinW, ZhaoQ, LiuD-X, YangZ, LiangP-P, SunS-S. QIU Zhen. Shale gas in China: Characteristics, challenges and prospects (II). Petroleum Exploration and Development, 2016, 43(2): 166-178

[2] ZouC-N, DongD-Z, WangY-M, LiX-J, HuangJ-L, WangS-F, GuanQ-Z, ZhangC-C, WangH-Y, LiuH-L, BaiW-H, LiangF, LinW, ZhaoQ, LiuD-X, YangZ, LiangP-P, SunS-S, QiuZ. Shale gas in China: Characteristics, challenges and prospects (I). Petroleum Exploration and Development, 2015, 42(6): 689-701

[3] GuoX-S. Rules of two-factor enrichiment for marine shale gas in Southern China: Understanding from the longmaxi formation shale gas in Sichuan basin and its surrounding area. Acta Geologica Sinica, 2014, 88(7): 1209-1218

[4] WangZ-G. Breakthrough of Fuling shale gas exploration and development and its inspiration. Oil & Gas Geology, 2015, 36(1): 1-6

[5] NieH-K, JinZ-J, BianR-K, DuW. The source-cap hydrocarbon-controlling”enrichment of shale gas in upper Ordovician Wufeng formation-lower Silurian longmaxi formation of Sichuan basin and its periphery. Acta Petrolei Sinica, 2016, 37(5): 557-571

[6] QinM-Y, GuoJ-H, HuangY-R, LiuC-S, ZhengZ-H, ZhangL-P, GuoJ, CaoZ. “Sweet spots zone” optimization of marine shale gas in complex geological conditions area out of Sichuan basin: A case of Paleozoic in Northwestern Hunan, China. Journal of Central South University: Science and Technology), 2019, 50(3): 596-606

[7] JinZ-J, HuZ-Q, GaoB, ZhaoJ-H. Controlling factors on the enrichment and high productivity of shale gas in the Wufeng-Longmaxi Formations, southeastern Sichuan Basin. Earth Science Frontiers, 2016, 23(1): 1-10

[8] LoucksR G, RuppelS C. Mississippian Barnett Shale: Lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas. AAPG Bulletin, 2007, 91(4): 579-601

[9] ZhaoW-Z, LiJ-Z, YangT, WangS-F, HuangJ-L. Geological difference and its significance of marine shale gases in South China. Petroleum Exploration and Development, 2016, 43(4): 499-510

[10] GuoT-L, ZhangH-R. Formation and enrichment mode of Jiaoshiba shale gas field, Sichuan Basin. Petroleum Exploration and Development, 2014, 41(1): 28-36

[11] LiZ-W, GuoJ-H, QinM-Y, HuangY-R, CaoZ. Differences and significance of shale gas accumulation in complex geological condition area: A case of Paleozoic in northwestern Hunan. Journal of Central South University: Science and Technology, 2020, 51(2): 385-398

[12] JiaL-L, DaiT-G, YouX-J, LiuY, FuS-W. Trace element geochemistry of V-Ni-Mo deposits from the Lower Cambrian black rock series of Northwestern Hunan. Earth Science Frontiers, 2012, 19(4): 260-265

[13] ChenX-H, WeiK, ZhangB-M, LiP-J, LiH, LiuA, LuoS-Y. Main geological factors controlling shale gas reservior in the Cambrian Shuijingtuo Formation in Yichang of Hubei Province as well as its and enrichment patterns. Geology in China, 2018, 45(2): 207-226

[14] LiuZ-B, GaoB, ZhangY-Y, DuW, FengD-J, NieH-K. Types and distribution of the shale sedimentary facies of the Lower Cambrian in Upper Yangtze area, South China. Petroleum Exploration and Development, 2017, 44(1): 21-31

[15] QiuX-S, HuM-Y, HuZ-G. Lithofacies palaeogeographic characteristics and reservoir-forming conditions of shale gas of lower Cambrian in middle Yangtze region. Journal of Central South University: Science and Technology, 2014, 45(9): 3174-3185

[16] XuZ-Y, JiangS, XiongS-Y, LiangX, WangG-C, GuoY-L, HeY, RaoD-Q. Characteristics and depositional model of the lower Paleozoic organic rich shale in the Yangtze continental block. Acta Sedimentologica Sinica, 2015, 33(1): 21-35

[17] LiuA, LiX-B, WangC-S, WeiK, WangB-Z. Analysis of geochemical feature and sediment environment for hydrocarbon source rocks of Cambrian in west Hunan-Hubei area. Acta Sedimentologica Sinica, 2013, 31(6): 1122-1132

[18] JiaZ-B, HouD-J, SunD-Q, JiangY-H, ZhaoZ, ZhangZ-M, HongM, ChangZ, DongL-C. Genesis and intensity of hydrothermal sedimentation in hydrocarbon source rocks in the Lower Cambrian Niutitang Formation, Guizhou area. Oil & Gas Geology, 2018, 39(3): 429-437

[19] ZhouL, WangZ-X, LiH-J, ZhangL-Y, ZhangK-X, LiangM-L. Accumulation pattern of organic matter in shales of the lower Cambrian niutitang formation, Chuandong-Wulingshan area. Journal of Geomechanics, 2018, 24(5): 617-626

[20] LiM-C, DingH, JiaoK, YaoS-P. Organic petrology of niutitang formation in sancha, western Hunan Province, China. Natural Gas Geoscience, 2012, 23(6): 1077-1089

[21] ChenX-H, WangC-S, LiuA, LuoS-Y, LiH, WeiK. The discovery of the shale gas in the Cambrian Shuijingtuo Formation of Yichang area, Hubei Province. Geology in China, 2017, 44(1): 188-189

[22] LiangF, ZhuY-M, MaC, ZhouH-Y, WangH-Y, BaiW-H, ZhangQ, CuiH-Y. Sedimentary distribution and reservoir characteristics of shale gas reservoir of Niutitang Formation in Northwestern Hunan. Journal of China Coal Society, 2015, 40(12): 2884-2892

[23] FengL-J, LiC, HuangJ, ChangH-J, ChuX-L. A sulfate control on marine mid-depth euxinia on the early Cambrian (Ca. 529-521Ma) Yangtze platform, South China. Precambrian Research, 2014, 246: 123-133

[24] ChengM, LiC, ZhouL, FengL-J, AlgeoT J, ZhangF-F, RomanielloS, JinC-S, LingH-F, JiangS-Y. Transient deep-water oxygenation in the early Cambrian Nanhua Basin, South China. Geochimica et Cosmochimica Acta, 2017, 210: 42-58

[25] QinM-Y, CaoZ, GuoJ-H, HuangY-R, SunL-P, DongL. Characteristics of shale reservoir and sweet spot identification of the lower Cambrian niutitang formation in northwestern Hunan Province, China. Acta Geologica Sinica — English Edition, 2019, 93(3): 573-587

[26] MengF-Y, ChenK, BaoS-J, LiH-H, ZhangC, WangJ-Z. Gas-bearing property and main controlling factors of Lower Cambrian shale in complex tectonic area of northwestern Hunan province: A case of well Ciye 1. Lithologic Reservoirs, 2018, 30(5): 29-39

[27] LinT, ZhangJ-C, LiB, HeW, TangX, MaL-R, PeiS-W. Shale gas accumulation conditions and gas-bearing properties of the Lower Cambrian Niutitang Formation in Well Changye 1, northwestern Hunan. Acta Petrolei Sinica, 2014, 35(5): 839-846

[28] ZhangH, WuJ, JinX-L, LinB-W. The genetic type and its geological indication significance of shale minerals in Niutitang Formation. Coal Geology & Exploration, 2018, 46(2): 61-67

[29] LiangY, HouD-J, ZhangJ-C. Hydrothermal activities on the seafloor and evidence of organic-rich source rock from the lower Cambrian Niutitang formation, northwestern Guizhou. Petroleum Geology and Recovery Efficiency, 2014, 21(4): 28-32113

[30] ZhaiG-Y, LiJ, JiaoY, WangY-F, LiuG-H, XuQ, WangC, ChenR, GuoX-B. Applications of chemostratigraphy in a characterization of shale gas sedimentary microfacies and predictions of sweet spots: Taking the Cambrian black shales in western Hubei as an example. Marine and Petroleum Geology, 2019, 109: 547-560

[31] WangS-F, ZouC-N, DongD-Z, WangY-M, HuangJ-L, GuoZ-J. Multiple controls on the paleoenvironment of the Early Cambrian marine black shales in the Sichuan Basin, SW China: Geochemical and organic carbon isotopic evidence. Marine and Petroleum Geology, 2015, 66: 660-672

[32] YanJ-F, MenY-P, SunY-Y, YuQ, LiuW, ZhangH-Q, LiuJ, KangJ-W, ZhanS-N, BaiH-H, ZhengX. Geochemical and geological characteristics of the Lower Cambrian shales in the middle-upper Yangtze area of South China and their implication for the shale gas exploration. Marine and Petroleum Geology, 2016, 70: 1-13

[33] ChenH-D, NiX-F, TianJ-C, CheD-X. Sequence stratigraphic framework of marine lower assemblage in South China and petroleum exploration. Oil & Gas Geology, 2006, 27(3): 370-377

[34] ZhouL, KangZ-H, WangZ-X, PengY-Y, XiaoH-F. Sedimentary geochemical investigation for paleoenvironment of the lower Cambrian Niutitang formation shales in the Yangtze platform. Journal of Petroleum Science and Engineering, 2017, 159: 376-386

[35] ChenD-Z, WangJ-G, QingH-R, YanD-T, LiR-W. Hydrothermal venting activities in the Early Cambrian, South China: Petrological, geochronological and stable isotopic constraints. Chemical Geology, 2009, 258(3/4): 168-181

[36] JiangT, JinZ-J, LiuG-X, LiuQ-Y, GaoB, LiuZ-B, NieH-K, ZhaoJ-H, WangR-Y, ZhuT, YangT. Source analysis of siliceous minerals and uranium in Early Cambrian shales, South China: Significance for shale gas exploration. Marine and Petroleum Geology, 2019, 102: 101-108

[37] LiuZ-B, GaoB, ZhangY-Y, DuW, FengD-J, NieH-K. Types and distribution of the shale sedimentary facies of the Lower Cambrian in Upper Yangtze area, South China. Petroleum Exploration and Development, 2017, 44(1): 21-31

[38] HanT, FanH-F, ZhuX-Q, WenH-J, ZhaoC-H, XiaoF. Submarine hydrothermal contribution for the extreme element accumulation during the early Cambrian, South China. Ore Geology Reviews, 2017, 86: 297-308

[39] ChengM, LiC, ZhouL, ZhangF-F, RomanielloS, JinC-S, LeiL-D, FengL-J, JiangS-Y. Marine Mo biogeochemistry in the context of dynamically euxinic mid-depth waters: a case study of the lower Cambrian Niutitang shales, South China. Geochimica et Cosmochimica Acta, 2016, 183: 79-93

[40] WangX-Q, ShiX-Y, ZhaoX-K, TangD-J. Increase of seawater Mo inventory and ocean oxygenation during the early Cambrian. Palaeogeography, Palaeoclimatology, Palaeoecology, 2015, 440: 621-631

[41] HanT, ZhuX-Q, LiK, JiangL, ZhaoC-H, WangZ-G. Metal sources for the polymetallic Ni-Mo-PGE mineralization in the black shales of the lower Cambrian niutitang formation, South China. Ore Geology Reviews, 2015, 67: 158-169

[42] ChangH-J, ChuX-L, FengL-J, HuangJ, ChenY-L. Marine redox stratification on the earliest Cambrian (Ca. 542–529 Ma) Yangtze Platform. Palaeogeography, Palaeoclimatology, Palaeoecology, 2018, 504: 75-85

[43] ZuoJ-X, PengS-C, QiY-P, ZhuX-J, BagnoliG, FangH-B. Carbon-isotope excursions recorded in the Cambrian system, South China: Implications for mass extinctions and sea-level fluctuations. Journal of Earth Science, 2018, 29(3): 479-491

[44] ZhangJ-P, FanT-L, AlgeoT J, LiY-F, ZhangJ-C. Paleo-marine environments of the early Cambrian Yangtze platform. Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 443: 66-79

[45] ZhaiL-N, WuC-D, YeY-T, ZhangS-C, WangY-Z. Fluctuations in chemical weathering on the Yangtze Block during the Ediacaran-Cambrian transition: Implications for paleoclimatic conditions and the marine carbon cycle. Palaeogeography, Palaeoclimatology, Palaeoecology, 2018, 490: 280-292

[46] GaoP, LiuG-D, JiaC-Z, YoungA, WangZ-C, WangT-S, ZhangP-W, WangD-P. Redox variations and organic matter accumulation on the Yangtze carbonate platform during Late Ediacaran-Early Cambrian: Constraints from petrology and geochemistry. Palaeogeography, Palaeoclimatology, Palaeoecology, 2016, 450: 91-110

[47] QinM-Y, GuoJ-H, HuangY-R, JiaoP, ZhengZ-H, QingY-B, WuS-Q. Characteristics and influencing factors of shale reservoirs in the Niutitang Formation of northwestern Hunan Province, and east margin of Sichuan Basin. Oil & Gas Geology, 2017, 38(5): 922-932