Geochemical characteristics of source rocks and oil-source correlation in Kaiping sag, Pearl River Mouth Basin

被引：0
作者：
Peng G. [1 ,2 ]
Guo J. [3 ,4 ]
Jiang F. [3 ,4 ]
Jiang D. [2 ]
Wu Y. [3 ,4 ]
Chen Z. [1 ,2 ]
Song Z. [3 ,4 ]
Gao Z. [1 ,2 ]
Zhang Y. [3 ,4 ]
机构：
[1] Shenzhen Branch, CNOOC China Ltd., Guangdong, Shenzhen
[2] CNOOC Deepivater Development Co., Ltd., Guangdong, Shenzhen
[3] National Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum {Beijing), Beijing
[4] College of Geosciences, China University of Petroleum (Beijing), Beijing
来源：
Shiyou Xuebao/Acta Petrolei Sinica | 2023年 / 44卷 / 10期
关键词：
geochemical characteristics; Kaiping sag; oil-source correlation; Pearl River Mouth Basin; source rock;
D O I：
10.7623/syxb202310004
中图分类号：
学科分类号：
摘要：
In Pearl River Mouth Basin, Kaiping sag is located in the deep-water; continental slope area beyond the existing continental shelf slope break zone, where oil and gas resources are less explored. It is of great significance to carry out source rock evaluation and clarify its crude oil source for deepening the understandings of oil and gas accumulation in Kaiping sag and guiding the next step of oil and gas exploration. Based on the test data including TOC content, rock pyrolysis, source rock and crude oil biomarker characteristics, the paper systematically analyzes the geochemical characteristics of source rocks of Wenchang Formation and Enpmg Formation, and conducts the oil-source correlation. The results show that: (1) The argillaceous source rocks of the Lower and Upper Wenchang Formation and Lower Enping Formation tend to be thick in the core area of Kaiping sag and gradually thinned towards the peripheral slope zone, of which the medium to high organic matter abundance and Type II iII2 kerogen demonstrate that they are in the mature stage as a whole. (2) The source rocks of Wenchang Formation has the low values of Pr/Ph, C19 + 2oTT/C23TT and low to medium OL/C30H. C27-C2S-C29 regular steranes on the gas chromatography-mass spectrum present "V" shape, and C, „ 4-methyls-teranes have high abundance. The source rocks of Enping Formation have high values of Pr/Ph and C19 + 20TT/C23TT, as well as low values of OL/C30 H and low C30 4-methylsterane content, and the distribution of C27-C28-C2,, regular steranes shows an inverted "L" shaped pattern. (3) There are two types of crude oil produced from Kaiping sag. As for Type A oil, the Pr/Ph values are within the range of 1. 13 and 1. 82, the C,, + 2„TT/C23TT values range from 0. 32 to 0. 89, the OL/C30H values are between 0. 03 and 1. 02, and the average relative content of C27 and C2., regular steranes is 26. 20% and 46. 44%, respectively. The C30 4-methylsteranes have high abundance. As for Type B oil, the Pr/Ph values are greater than 2. 00, the Cu + 20TT/C23TT values are between 1. 00 and 2. 28, the OL/C30H values range from 0. 04 to 0. 13, and the average relative content of C27 and C29 regular steranes is 9. 92% and 65. 54%, respectively. The content of C30 4-methylsteranes is extremely low. (4) Oil-source correlation analysis shows that Type A oil is originated from the hybrid organic matters of Type TJ and m formed by plankton and terrestrial plants in lacustrine source rock of Wen-chang Formation; Type B oil comes from the deltaic swamp mudstone of Enping Formation in the background of oxidation sedimentation, and the hydrocarbon generation parent material is dominated by Type UJ organic matter formed by terrestrial higher plants. In conclusion, the research has clarified the sources of oil and gas in Kaiping sag, which is of theoretical guiding significance for future oil and gas exploration. © 2023 Science Press. All rights reserved.
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页码：1624 / 1636
页数：12
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