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Frontiers of Earth Science

ISSN 2095-0195

ISSN 2095-0209(Online)

CN 11-5982/P

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Front. Earth Sci.    2021, Vol. 15 Issue (2) : 423-437    https://doi.org/10.1007/s11707-020-0867-4
RESEARCH ARTICLE
Fine-grained rock fabric facies classification and its control on shale oil accumulation: a case study from the Paleogene Kong 2 Member, Bohai Bay Basin
Wenzhong HAN1,2, Xianzheng ZHAO2, Xiugang PU2, Shiyue CHEN1(), Hu WANG2, Yan LIU3, Zhannan SHI2, Wei ZHANG2, Jiapeng WU2
1. School of Earth Science and technology, China University of Petroleum (East China), Qingdao 266580, China
2. Dagang Oil Field Company of PetroChina, Tianjin 300280, China
3. Key Laboratory of Exploration Technologies for Oil and Gas Resources (Ministry of Education), Yangtze University, Wuhan 430100, China
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Abstract

Lacustrine shale oil resources in China are abundant, with remarkable exploration breakthroughs being achieved. Compared to marine shale oil in North America, efficient exploration of lacustrine shale oil is more difficult; thus, selecting favorable layer and optimization zone for horizontal wells is more important. In this study, based on systematic coring of approximately 500 m fine-grained deposits of the Kong 2 Member, combining laboratory tests and log data, source rock geochemistry and reservoir physical properties, the favorable rock fabric facies for oil accumulation was analyzed and classified. First, the dominant lithologic facies, organic facies, and bed combination facies were determined based on mineral composition from logging, total organic content (TOC), and sedimentary structure. Secondly, 10 fabric facies were classified by combining these three facies, with 4 fabric facies were found to have high TOC content, high total hydrocarbon, and strong fluorescence features, indicating good shale oil enrichment. Thirdly, the distribution of the upon good fabric facies was identified to be located at the top of the Kong 2 Member, with evidences of seismic resistivity inversion, thermal maturity, structure depth, and strata thickness. And the favorable facies were found to be stably distributed lateral at the area of about 100 km2. High oil flow has been detected at this layer within this area by several wells, including horizontal wells. The exploratory study of fabric facies classification and evaluation provides a new research idea for lacustrine shale oil exploration and effectively promotes breakthroughs in lacustrine shale oil exploration in Bohai Bay Basin.
Keywords fabric facies      fine grained deposits      lithologic facies      organic facies      Bohai Bay Basin     
Corresponding Author(s): Shiyue CHEN   
Online First Date: 26 March 2021    Issue Date: 26 October 2021
 Cite this article:   
Wenzhong HAN,Xianzheng ZHAO,Xiugang PU, et al. Fine-grained rock fabric facies classification and its control on shale oil accumulation: a case study from the Paleogene Kong 2 Member, Bohai Bay Basin[J]. Front. Earth Sci., 2021, 15(2): 423-437.
 URL:  
https://academic.hep.com.cn/fesci/EN/10.1007/s11707-020-0867-4
https://academic.hep.com.cn/fesci/EN/Y2021/V15/I2/423
Fig.1  Sedimentary system of Ek21 in the Cangdong sag.
Fig.2  Major fabric facies types of Ek21 in Well G108-8.
Fig.3  Fabric facies division in Kong 2 Member of the Cangdong sag.
No. Lithologic facies Organic facies Layer combination Fabric facies type
Rock type Ratio of dolomite to gross (%) Organic facies TOC
(%)		 Sedimentary structure Single layer thickness from log interpretation Fabric facies Sub-facies Sub-type
Dominant fabric facies Organic facies+ dominant fabric facies Layer combination+Organic facies+ dominant fabric facies
1 Dolomite >75 High TOC >3 Thick sandwiched form Thick layer (>2 m) Dolomite facies
Argillaceous dolomite
Mixed rock of mudstone and dolomite
Dolomitic mudstone
Mud-shale		 For instance :High TOC dolomitic mudstone facies,
Up to 15 sub facies associations can be formed		 Layered cake high TOC thin argillaceous dolomite etc., up to 45 subtypes.
2 Argillaceous dolomite 60-75
3 Mixed rock of shale and dolomite 40-60 Moderate TOC 1-3 Interbed form Medium layer (1–2 m)
4 Dolomitic shale 25-40
5 shale <25 Low TOC <1 Layered cake form Thin layer (<1 m)
Tab.1  Fabric facies classification and naming scheme of shale in the Cangdong sag
Lithology Major fracture pore system Microscopic photo Macroscopic photo Porosity/% Permeability/mD
Shale Bedding fracture
~
Intergranular pore
~
Organic matter nano-pore 		3.3 0.17
Dolomitic Shale Intergranular pore
~
Bedding fracture
~
Micro fracture		 3.1 0.12
Argillaceous dolomite Intercrystalline pore
~
Bedding fracture
~
Micro fracture		 5.2 0.28
Dolomite Intercrystalline pore
~
Micro fracture		 7.5 0.56
Tab.2  Fracture and pore system in fine grained sediments of Kong 2 Member in the Cangdong sag
Fig.4  Main types of fabric facies in Kong 2 Member of the Cangdong sag.
Types M-1 M-2 M-3 I-1 I-2 I-3 S-1 S-2 S-3 S-4
Dolomite ratio /% 40-60 60-75 25-40 40-60 60-75 25-40 0-25 0-25 75-100 75-100
Average porosity/% 4.5 5.1 3.5 5.2 5.8 4.9 3.1 3.4 6.7 8.7
Fluorescence Moderate Low-moderate Moderate Moderate Low-moderate Moderate Strong Strong Low Low
S1/mg·g-1 3.6 2.1 4.1 2.5 1.1 3.3 5.7 6.3 0.7 0.5
Average TOC/% 4.3 2.8 3.6 2.7 1.9 3.1 4.8 5.0 1.0 0.8
Fabricfeature Layered cake form Interbed form Thick sandwich form
Log curve structure Micro-serrate Serrate Box-like
Tab.3  Features of shale fabric facies of Kong 2 Member in the Cangdong sag
Fig.5  Comparison of fabric facies of Ek21 in different parts based on log interpretation.
Fig.6  The porosity, free hydrocarbon and TOC bar chart of different fabric facies.
Fig.7  Oil production of different fabric facies.
Fig.8  Favorable sweet spots of S-1 fabric facies in Ek21 fine grained facies belt of the Cangdong sag.
Fig.9  Oil testing curve of GD1702H in Ek21.
1 S A Akinyemi, O F Adebayo, B B Nyakuma, A K Adegoke, O A Aturamu, O A OlaOlorun, A Adetunji, J C Hower, M M Hood, A Jauro (2020). Petrology, physicochemical and thermal analyses of selected cretaceous coals from the Benue Trough Basin in Nigeria. Int J Coal Sci Technol, 7(1): 26–42
https://doi.org/10.1007/s40789-020-00303-6
2 S Chen, S Zhang, Y Wang, M Tan (2016). Lithofacies types and reservoirs of paleogene fine-grained sedimentary rocks dongying sag, Bohai Bay Basin, china. Pet Explor Dev, 43(2): 218–229
https://doi.org/10.1016/S1876-3804(16)30025-8
3 J Cui, R Zhu, Z Mao, S Li (2019). Accumulation of unconventional petroleum resources and their coexistence characteristics in Chang 7 shale formations of Ordos Basin in central China. Front Earth Sci, 13(3): 575–587
https://doi.org/10.1007/s11707-019-0756-x
4 J H Fu, X Q Deng, M J Chu, H F Zhang, S X Li (2013). Features of deepwater Lithofacies, Yanchang Formation in Ordos Basin and its petroleum significance. Acta Sedimentology Sinica, 5: 928–938
5 S Geng (2013). Study on shale mineral component content model in Luojia area. Petroleum Geology and Recovery Efficiency, 1: 24–27
6 J Gu, Y J Huang, C Wang (2010). Mudstone lithofacies in the Cretaceous Qingshankou Formation of Well Sk I, Songliao Basin, Northeastern China. China Mining Magazine, 19: 161–165
7 DM Jarvie, RJ Hill, T E Ruble, R M Pollastro. (2007) Unconventional shale-gas systems: the Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment. AAPG Bulletin 91: 475–499
https://doi.org/10 .1306 /12190606068 .
8 C Z Jia, C N Zou, J Z Li, D H Li, M Zheng (2012). Assessment criteria, main types, basic features and resource prospects of the tight oil in China. Acta Petrol Sin, 3: 343–350
9 Z Jin, Y Sun, L Yang (2001). Influences of deep fluids on organic matter of source rocks from the Dongying Depression, East China. Energy Exploration & Exploitation, 19(5): 479–486
https://doi.org/10.1260/0144598011492606
10 S Z Li, Y H Suo, L H Zhou, L M Dai, J T Zhou, F M Zhao, Y Lu, X G Pu, D Lou, Q Wu, Q Jiao (2011). Pull-apart basins within the North China Craton, structural pattern and evolution of Huanghua Depression in Bohai Bay Basin. Journal of Jilin University (Earth Science Edition), 5: 1362–1379
11 Y Li, Z Wang, Z Pan, X Niu, Y Yu, S Meng (2019b). Pore structure and its fractal dimensions of transitional shale: a cross section from east margin of the Ordos Basin, China. Fuel, 241: 417–431
https://doi.org/10.1016/j.fuel.2018.12.066
12 Y Li, X Gao, S Meng, P Wu, X Niu, P Qiao, D Elsworth (2019a). Diagenetic sequences of continuously deposited tight sandstones in various environments: a case study from upper Paleozoic sandstones in the Linxing area, eastern Ordos Basin, China. AAPG Bull, 103(11): 2757–2783
https://doi.org/10.1306/03061918062
13 Y Li, J Yang, Z Pan, S Meng, K Wang, X Niu (2019c). Unconventional natural gas accumulations in stacked deposits: a discussion of Upper Paleozoic coal-bearing strata in the east margin of the Ordos Basin, China. Acta Geol Sin, 93(1): 111–129
https://doi.org/10.1111/1755-6724.13767
14 Y Li, J Yang, Z Pan, W Tong (2020). Nanoscale pore structure and mechanical property analysis of coal: an insight combining AFM and SEM images. Fuel, 260: 116352
https://doi.org/10.1016/j.fuel.2019.116352
15 J H S Macquaker, A E Adams (2003). Maximizing information from fine-grained sedimentary rocks: an inclusive nomenclature for mudstones. J Sediment Res, 73(5): 735–744
https://doi.org/10.1306/012203730735
16 J H S Macquaker, M A Keller S J Davies (2010) Algal blooms and “marine snow”: mechanisms that enhance preservation of organic carbon in ancient fine-grained sediments: Journal of Sedimentary Research, 80: 934–942
https://doi.org/10 .2110 /jsr .2010 .085
17 X G Pu, W Z Han, L H Zhou, S Y Chen, W Zhang, Z N Shi, F Yang, S Liu (2015). Lithologic characteristics and geological implication of fine-grained sedimentation in Ek2 high stand system tract of Cangdong Sag, Huanghua Depression. China Petroleum Exploration, 5: 30–40
18 X G Pu, L H Zhou, W Z Han, J S Zhou, W G Wang, W Zhang, S Y Chen, Z N Shi, S Liu (2016). Geologic features of fine-grained facies sedimentation and tight oil exploration: a case from the second Member of Paleogene Kongdian Formation of Cangdong Sag, Bohai Bay Basin. Pet Explor Dev, 43(1): 26–36
https://doi.org/10.1016/S1876-3804(16)30003-9
19 J Y Ren, Q J Liao, G C Lu, L X Fu, J Y Zhou, P Qi, S S Shi (2010). Deformation framework and evolution of Huanghua Depression, Bohai Gulf. Geotectonica et Metallogenia, 4: 461–472
20 R M Slatt (2007). Introduction to the petroleum geology of deepwater setting. In Weimer P and Slatt RM, eds. Introduction to the Petroleum Geology of Deepwater Setting. AAPG Bull, 57: 1–18
21 Y Wang, X J Wang, G Q Song, H Liu, D Zhu, D Zhu, J Ding, W Yang, Y Yin, S Zhang, M Wang (2016). Genetic connection between mud shale lithofacies and shale oil enrichment in Jiyang Depression, Bohai Bay Basin. Pet Explor Dev, 43(5): 759–768
https://doi.org/10.1016/S1876-3804(16)30091-X
22 Y S Wang, Z Li, J Q Gong (2013). Discussion on an evaluation method of shale oil and gas in Jiyang depression, a case study on Luojia area in Zhuanhua Sag. Acta Petrol Sin, 1: 83–91
23 Y T Yang, J C Zhang, X Z Wang, J Z Cao, X Tang, L Wang, S Y Yang (2012). Source rock evaluation of lacustrine shale gas, A case study of Chang 7 of Mesozoic Yanchang Formation in Xiasiwan area of Yanchang. Journal of Northeast Petroleum University, 4: 10–17
24 Z Yang, L H Hou, S Z Tao, J W Cui, S T Wu, S H Lin, S Q Pan (2015). Formation conditions and “sweet spot” evaluation of tight oil and shale oil. Pet Explor Dev, 42(5): 555–566
25 S Zhang, S Y Chen, S L Cui, W L Gong, J Q Yu, J H Yan, P C Shao, Y Liu. (2014) Characteristics and types of fine grained sedimentary rocks lithofacies in semi-deep and deep lacustrine, Dongying Sag. Journal of China University of Petroleum 5: 9–17
26 X Z Zhao, X G Pu, W Z Han, L H Zhou, Z N Shi, S Y Chen, D Q Xiao (2017). A new method for lithology identification of fine grained deposits and reservoir sweet spot analysis: a case study of Kong 2 Member in Cangdong sag, Bohai Bay Basin, China. Pet Explor Dev, 44(4): 524–534
https://doi.org/10.1016/S1876-3804(17)30061-7
27 X Z Zhao, L H Zhou, X G Pu, W Z Han, F M Jin, D Q Xiao, Z N Shi, Y Deng, W Zhang, W Y Jiang (2019). Exploration breakthroughs and geological characteristics of continental shale oil: a case study of the Kongdian Formation in the Cangdong Sag, China. Mar Pet Geol, 102: 544–556
https://doi.org/10.1016/j.marpetgeo.2018.12.020
28 X Z Zhao, L H Zhou, X G Pu, F M Jin, W Z Han, D Q Xiao, S Y Chen, Z N Shi, W Zhang, F Yang (2018). Geological characteristics of shale rock system and shale oil exploration breakthrough in a lacustrine basin: a case study from the Paleogene 1st submember of Kong 2 Member in Cangdong sag, Bohai Bay Basin, China. Pet Explor Dev, 45(3): 377–389
https://doi.org/10.1016/S1876-3804(18)30043-0
29 Z Z Zhao, J H Du (2012) Tight Oil and Gas. Beijing: Petroleum Industry Press: 125–143 (in Chinese)
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