Geochemical Characteristics and Hydrocarbon Generation Potential of Miocene Marine Source Rocks in the Ying-Qiong Basin

doi:10.19657/j.geoscience.1000-8527.2018.03.08

Abstract

Abstract:

Based on the analysis of organic carbon,rock-eval pyrolysis,maceral identification,saturated hydrocarbon chromatography and chromatography-mass spectrometry,geochemical characteristics of the Miocene marine source rocks in the Ying-Qiong Basin were studied. The hydrocarbon generation potentials of different source rocks were discussed. The results indicate that the organic matter abundance of the Miocene marine source rocks are generally low, most of which are medium source rocks. Organic matters comprise mainly type Ⅱ₂ and Ⅲ, and their thermal evolution is mainly in the mature stage. The maceral composition of the studied samples is dominated by vitrinites, and the inertinite contents are relatively low. Sedimentary environment of the source rocks was weakly oxidizing to weakly reducing, and the organic matter may have be originated from terrestrial higher plants and lower aquatic algae. Comprehensive source rock evaluation on the Meishan Formation in the Yinggehai Basin indicates that they are medium source rocks with relatively high hydrocarbon generation potential, whereas source rocks of the Sanya Formation are poor-medium ones and have minor hydrocarbon generation potential. The Meishan and Sanya formations in the Qiongdongnan Basin contain medium source rocks, and have certain hydrocarbon generation potential.

Key words: marine source rocks, geochemical characteristics, maceral, biomarkers, hydrocarbon generation potential, Ying-Qiong Basin

CLC Number:

TE122.1

WANG Yuan, LI Xianqing, WANG Gang, XU Xinde, LIU Haiyu. Geochemical Characteristics and Hydrocarbon Generation Potential of Miocene Marine Source Rocks in the Ying-Qiong Basin[J]. Geoscience, 2018, 32(03): 500-510.

Figures/Tables 14

Fig.1 Tectonic belt of the Ying-Qiong Basin and the wells locations of sampling

Fig.2 Schematic stratigraphic column of the Ying-Qiong Basin

Table 1 Parameters of organic matter abundance of source rocks from the different formations in the Ying-Qiong Basin

盆地	层位	TOC/%	PG/(mg/g)	“A”/%	HC/10^-6
莺歌海	梅山组	$0.15 ~ 4.51 0.51 (107)$	$0.12 ~ 3.4 0.99 (111)$	$0.002 ~ 0.098 0.046 (38)$	$26.8 ~ 519.1 166.1 (28)$
莺歌海	三亚组	$0.2 ~ 0.97 0.41 (26)$	$0.12 ~ 1.87 0.65 (23)$	$0.014 ? 8 ~ 0.065 ? 9 0.040 ? 2 (11)$	$22.82 ~ 499.5 230.6 (10)$
琼东南	梅山组	$0.1 ~ 2.97 0.65 (107)$	$0.02 ~ 3.76 0.92 (84)$	$0.004 ? 1 ~ 0.090 ? 5 0.033 (21)$	$43.7 ~ 546 196.8 (17)$
琼东南	三亚组	$0.07 ~ 2.86 0.63 (51)$	$0.02 ~ 1.87 0.81 (41)$	$0.020 ~ 0.092 0.057 (14)$	$47.9 ~ 595.7 243.6 (12)$

Table 1 Parameters of organic matter abundance of source rocks from the different formations in the Ying-Qiong Basin

盆地	层位	TOC/%	PG/(mg/g)	“A”/%	HC/10^-6
莺歌海	梅山组	$0.15 ~ 4.51 0.51 (107)$	$0.12 ~ 3.4 0.99 (111)$	$0.002 ~ 0.098 0.046 (38)$	$26.8 ~ 519.1 166.1 (28)$
莺歌海	三亚组	$0.2 ~ 0.97 0.41 (26)$	$0.12 ~ 1.87 0.65 (23)$	$0.014 ? 8 ~ 0.065 ? 9 0.040 ? 2 (11)$	$22.82 ~ 499.5 230.6 (10)$
琼东南	梅山组	$0.1 ~ 2.97 0.65 (107)$	$0.02 ~ 3.76 0.92 (84)$	$0.004 ? 1 ~ 0.090 ? 5 0.033 (21)$	$43.7 ~ 546 196.8 (17)$
琼东南	三亚组	$0.07 ~ 2.86 0.63 (51)$	$0.02 ~ 1.87 0.81 (41)$	$0.020 ~ 0.092 0.057 (14)$	$47.9 ~ 595.7 243.6 (12)$

Fig.3 TOC content frequency distribution of source rocks from the different formations in the Ying-Qiong Basin

Fig.4 Hydrocarbon generation potential frequency distribution of source rocks from the different formations in the Ying-Qiong Basin

Fig.5 Assessment of organic matter abundance of source rocks from the different formations in the Ying-Qiong Basin

Fig.6 IH—Tmax and IH—IO of source rocks from the different formations in the Ying-Qiong Basin

Fig.7 Frequency distribution of Ro of source rocks from the different formations in the Ying-Qiong Basin

Table 2 Statistics of macerals in source rocks of the different formations in the Ying-Qiong Basin

盆地	层位	显微组分含量(占全岩体积)/%
盆地	层位	TMCS₃	TMC	V	I	E	S	S₃
莺歌海	梅山组	$0.4 ~ 8 3.23 (42)$	$0.2 ~ 3.6 1.09 (42)$	$0.2 ~ 3.6 0.88 (42)$	$微 ~ 0.6 微 (42)$	$微 ~ 0.4 0.1 (42)$	$微 ~ 0.2 微 (42)$	$微 ~ 7 2.14 (42)$
莺歌海	三亚组	$0.4 ~ 11 4.36 (9)$	$0.4 ~ 2.2 1.02 (9)$	$0.4 ~ 2 0.87 (9)$	$微 ~ 0.2 微 (9)$	$微 ~ 0.2 0.11 (9)$	微(9)	$微 ~ 10.2 3.33 (9)$
琼东南	梅山组	$0.2 ~ 1.4 0.6 (24)$	$0.2 ~ 1.4 0.39 (24)$	$0.2 ~ 1 0.35 (24)$	$微 ~ 0.4 微 (24)$	$微 ~ 0.2 微 (24)$	微(24)	$微 ~ 1.2 0.21 (24)$
琼东南	三亚组	$0.2 ~ 4 1.35 (21)$	$0.2 ~ 2.6 0.92 (21)$	$0.2 ~ 2.4 0.82 (21)$	微(21)	$微 ~ 0.2 微 (21)$	$微 ~ 0.4 微 (21)$	$微 ~ 3.8 0.43 (21)$

Table 2 Statistics of macerals in source rocks of the different formations in the Ying-Qiong Basin

盆地	层位	显微组分含量(占全岩体积)/%
盆地	层位	TMCS₃	TMC	V	I	E	S	S₃
莺歌海	梅山组	$0.4 ~ 8 3.23 (42)$	$0.2 ~ 3.6 1.09 (42)$	$0.2 ~ 3.6 0.88 (42)$	$微 ~ 0.6 微 (42)$	$微 ~ 0.4 0.1 (42)$	$微 ~ 0.2 微 (42)$	$微 ~ 7 2.14 (42)$
莺歌海	三亚组	$0.4 ~ 11 4.36 (9)$	$0.4 ~ 2.2 1.02 (9)$	$0.4 ~ 2 0.87 (9)$	$微 ~ 0.2 微 (9)$	$微 ~ 0.2 0.11 (9)$	微(9)	$微 ~ 10.2 3.33 (9)$
琼东南	梅山组	$0.2 ~ 1.4 0.6 (24)$	$0.2 ~ 1.4 0.39 (24)$	$0.2 ~ 1 0.35 (24)$	$微 ~ 0.4 微 (24)$	$微 ~ 0.2 微 (24)$	微(24)	$微 ~ 1.2 0.21 (24)$
琼东南	三亚组	$0.2 ~ 4 1.35 (21)$	$0.2 ~ 2.6 0.92 (21)$	$0.2 ~ 2.4 0.82 (21)$	微(21)	$微 ~ 0.2 微 (21)$	$微 ~ 0.4 微 (21)$	$微 ~ 3.8 0.43 (21)$

Fig.8 Ternary diagram of maceral composition of source rocks in the Ying-Qiong Basin

Fig.9 Chromatogram of the saturated hydrocarbons in source rocks from the different formations in the Ying-Qiong Basin

Fig.10 Mass chormatograms of terpenes (m/z 191) in source rocks from the different formations in the Ying-Qiong Basin

Fig.11 Mass chormatograms of steranes (m/z 217) in source rocks from the different formations in the Ying-Qiong Basin

Table 3 Hydrocarbon generation potential evaluation of the Miocene marine source rocks in the Ying-Qiong Basin

盆地	层位	烃源岩厚度/ m	TOC/%	PG/ (mg/g)	TMCS₃/%	TMC/%	Ro/%	Pr/Ph	C₂₉20S/ (20S+20R)	综合评价结果
莺歌海	梅山组	$42.5 ~ 570.5 375.3$	$0.15 ~ 4.51 0.51 (107)$	$0.12 ~ 3.4 0.99 (111)$	$0.4 ~ 8 3.23 (42)$	$0.2 ~ 3.6 1.09 (42)$	$0.23 ~ 1.04 0.67 (59)$	$0.31 ~ 5.06 2.14 (39)$	$0.32 ~ 0.65 0.43 (20)$	中等烃源岩
莺歌海	三亚组	$122.5 ~ 195.7 157.6$	$0.2 ~ 0.97 0.41 (26)$	$0.12 ~ 1.87 0.65 (23)$	$0.4 ~ 11 4.36 (9)$	$0.4 ~ 2.2 1.02 (9)$	$0.67 ~ 0.79 0.73 (14)$	$0.44 ~ 3.22 1.79 (10)$	$0.36 ~ 0.57 0.46 (4)$	较差-中等烃源岩
琼东南	梅山组	$36 ~ 337 172.3$	$0.1 ~ 2.97 0.65 (107)$	$0.02 ~ 3.76 0.92 (84)$	$0.2 ~ 1.4 0.6 (24)$	$0.2 ~ 1.4 0.39 (24)$	$0.29 ~ 1.36 0.69 (31)$	$0.51 ~ 5.19 1.58 (30)$	$0.16 ~ 0.61 0.40 (12)$	中等烃源岩
琼东南	三亚组	$14 ~ 803.7 276.3$	$0.07 ~ 2.86 0.63 (51)$	$0.02 ~ 1.87 0.81 (41)$	$0.2 ~ 4 1.35 (21)$	$0.2 ~ 2.6 0.92 (21)$	$0.35 ~ 1.35 0.67 (30)$	$0.41 ~ 4.73 1.8 (15)$	$0.37 ~ 0.78 0.49 (11)$	中等烃源岩

Table 3 Hydrocarbon generation potential evaluation of the Miocene marine source rocks in the Ying-Qiong Basin

盆地	层位	烃源岩厚度/ m	TOC/%	PG/ (mg/g)	TMCS₃/%	TMC/%	Ro/%	Pr/Ph	C₂₉20S/ (20S+20R)	综合评价结果
莺歌海	梅山组	$42.5 ~ 570.5 375.3$	$0.15 ~ 4.51 0.51 (107)$	$0.12 ~ 3.4 0.99 (111)$	$0.4 ~ 8 3.23 (42)$	$0.2 ~ 3.6 1.09 (42)$	$0.23 ~ 1.04 0.67 (59)$	$0.31 ~ 5.06 2.14 (39)$	$0.32 ~ 0.65 0.43 (20)$	中等烃源岩
莺歌海	三亚组	$122.5 ~ 195.7 157.6$	$0.2 ~ 0.97 0.41 (26)$	$0.12 ~ 1.87 0.65 (23)$	$0.4 ~ 11 4.36 (9)$	$0.4 ~ 2.2 1.02 (9)$	$0.67 ~ 0.79 0.73 (14)$	$0.44 ~ 3.22 1.79 (10)$	$0.36 ~ 0.57 0.46 (4)$	较差-中等烃源岩
琼东南	梅山组	$36 ~ 337 172.3$	$0.1 ~ 2.97 0.65 (107)$	$0.02 ~ 3.76 0.92 (84)$	$0.2 ~ 1.4 0.6 (24)$	$0.2 ~ 1.4 0.39 (24)$	$0.29 ~ 1.36 0.69 (31)$	$0.51 ~ 5.19 1.58 (30)$	$0.16 ~ 0.61 0.40 (12)$	中等烃源岩
琼东南	三亚组	$14 ~ 803.7 276.3$	$0.07 ~ 2.86 0.63 (51)$	$0.02 ~ 1.87 0.81 (41)$	$0.2 ~ 4 1.35 (21)$	$0.2 ~ 2.6 0.92 (21)$	$0.35 ~ 1.35 0.67 (30)$	$0.41 ~ 4.73 1.8 (15)$	$0.37 ~ 0.78 0.49 (11)$	中等烃源岩

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