A quick comparison of Pliocene and Upper Miocene shale resources in northern, central and southern parts of Song Hong basin with reference to their gas potential

  • Vo Thi Hai Quan Vietnam Petroleum Institute
  • Pham Huy Giao Vietnam Petroleum Institute & Petrovietnam University
Keywords: Song Hong basin, shale gas, Ken Bau discovery, Rock-Eval pyrolysis, vitrinite reflectance, XRD

Abstract

  This research is a follow-up of a more comprehensive PhD study on assessment of shale gas resources in the northern Song Hong basin that was conducted at the Asian Institute of Technology (AIT). The Song Hong basin, a typical pull-apart Cenozoic basin, had experienced a post-extensional stage accompanied by seafloor spreading from Upper Oligocene to Lower Miocene with its stratigraphy characterised by a fault-controlled syn-rift continental sequence followed by a post-rift marine sequence. In recent years, a number of gas fields have been discovered in the Song Hong basin with the Oligocene-Eocene and the Lower-Middle Miocene shales as the major and minor source rocks, respectively. On the other hand, the Pliocene and Upper Miocene shales, present in the stratigraphy from the north to the south of the Song Hong basin, have generally been considered as the seals, but not the source rocks in some previous studies. In July 2020, an exploration well (Ken Bau-2X) was drilled in Block 114 by ENI, reaching a total depth of 3,658 m and encountering a pay of about 110 m in several intervals of Upper Miocene sandstones interbedded with shales, confirming a considerable gas accumulations discovered in Vietnam so far. The interesting thing is that this well only encounter the Pliocene and Upper Miocene shales, the Oligocene-Eocene or Middle-Lower Miocene sediments underlying is absent or very thin. Therefore, potential source rock of these shales should be considered in the area, in particular with reference to petroleum system of the central Song Hong basin.

 

In this study, a preliminary comparison of the Pliocene and Upper Miocene shale resources in the northern, central and southern blocks in the Song Hong basin was conducted based on the analysis results of XRD, Rock-Eval pyrolysis, vitrinite reflectance, respectively. While the Pliocene and Upper Miocene shales in many areas of Song Hong basin, show a very low or no hydrocarbon generation potential, the very deep and thick Pliocene and Upper Miocene shales in the center and adjacent areas, deposited in a marine environment under the special conditions of abnormal pressure and high geothermal gradient, can be potential source rocks that have possibly generated and released a large amount of hydrocarbons. Further geochemical analyses and petroleum system modelling of the Pliocene and Upper Miocene shales in particular and for the whole central Song Hong basin are recommended.

References

ENI, "ENI confirms and expands gas and condensate potential in the Ken Bau discovery in Block 114, Song Hong basin, offshore Vietnam”, 27/7/2020. [Online]. Available: https://www.eni.com/en-IT/media/press-release/2020/07/eni-confirms-and-expands-gas-and-condensate-potential-in-the-ken-bau-discovery-in-block-114.html.

Tập đoàn Dầu khí Việt Nam, “Lô 114 - điểm sáng trong hoạt động tìm kiếm thăm dò ngoài khơi thềm lục địa Việt Nam”, 29/7/2020. [Online]. Available: http://pvn.vn/Pages/detail.aspx?NewsID=c80187ba-02e6-4562-a5e5-a2b03ff3b207.

Petrovietnam, The petroleum geology and resources of Vietnam, 2nd edition. Science and Technology Publication, 2019.

Vietnam Petroleum Institute, “Regional study of Song Hong and Phu Khanh basins, Blocks 105-110/4, 114 and 120”, 2014.

Connah Andersen, A. Mathiesen, Lars Henrik Nielsen, P.V. Tiem, Henrik I. Petersen, and P.T. Dien, “Distribution of source rocks and maturity modelling in the northern Cenozoic Song Hong basin (Gulf of Tonkin) Vietnam”, Journal of Petroleum Geology, Vol. 28, No. 2, pp. 167 - 184, 2005. DOI:10.1111/j.1747-5457.2005.tb00078.x.

Nguyen Thi Hong Lieu, “Holocene evolution of the central Red River delta, Northern Vietnam, lithological and mineralogical investigation”, PhD Thesis, Ernst-Moritz-Arndt-University, Greifswald, Germany, 2006.

Michael B.W. Fyhn, Henrik I. Petersen, Lars Henrik Nielsen, Tran C. Giang, Le H. Nga, Nguyen T.M. Hong, Nguyen D. Nguyen, and Ioannis Abatzis, “The Cenozoic Red River and Beibuwan basins, Vietnam”, Geologic Survey of Denmark and Greenland Bulletin, Vol. 26, No. 26, pp. 81 - 84, 2012. DOI: 10.34194/geusb.v26.4769.

L.H. Nielsen, A. Mathiesen, T. Bidstrup, O.V. Vejbaek, P.T. Dien, and P.V. Tiem, “Modelling of hydrocarbon generation in the Cenozoic Red River basin, Vietnam: A highly prospective basin”, Journal of Asian Earth Sciences, Vol. 17, pp. 269 - 294, 1999.

Vo Thi Hai Quan and Pham Huy Giao, “Visual kerogen typing: A case study of the Northern Song Hong basin, Vietnam”, in Advances in Petroleum Engineering and Petroleum Geochemistry. Springer, 2018, pp. 131 - 134. DOI: 10.1007/978-3-030-01578-7_31.

Vo Thi Hai Quan and Pham Huy Giao, “Geochemical evaluation of shale formations in the northern Song Hong basin, Vietnam”, Journal of Petroleum Exploration and Production Technology (JPEPT), Springer Nature, Vol. 9, pp. 1839 - 1853, 2019. DOI: 10.1007/s13202-019-0667-0.

Phạm Khoa Chiết, Nguyễn Thế Hùng, và Trần Đăng Hùng, “Đặc điểm tướng và môi trường trầm tích Miocen sớm - giữa khu vực Lô 102 - 106, Bắc bể Sông Hồng”, Tạp chí Khoa học Đại học Quốc gia Hà Nội: Các Khoa học Trái đất và Môi trường, Số 32, Tập 2S, trang 153 - 163, 2016.

Kevin McCarthy, Katherine Rojas, Martin Nienmann, Daniel Palmowski, Kenneth E. Peters, and Artur Stankiewicz, “Basic petroleum geochemistry for source rock evaluation”, Oilfield Review, Vol. 23, No. 2, pp. 32 - 43, 2011.

Kenneth E. Peters, “Guideline for evaluating petroleum source rocks using programmed pyrolysis”, The AAPG Bulletin, Vol. 70, No. 3, pp. 318 - 329, 1986. DOI: 10.1306/94885688-1704-11D7-8645000102C1865D.

Published
2022-11-01
How to Cite
Vo , T. H. Q., & Pham , H. G. (2022). A quick comparison of Pliocene and Upper Miocene shale resources in northern, central and southern parts of Song Hong basin with reference to their gas potential. Petrovietnam Journal, 10, 3 - 11. https://doi.org/10.47800/PVJ.2022.10-01
Section
Articles