| 基于古地貌和源-汇特征分析的烃源岩评价:以珠江口盆地阳江凹陷为例 |
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| 引用本文： | 彭光荣,杜晓东,姜素华,李三忠,关雪婷,魏董,姜衍,陆蕾蕾. 基于古地貌和源-汇特征分析的烃源岩评价:以珠江口盆地阳江凹陷为例[J]. 地学前缘, 2022, 29(5): 188-202. DOI: 10.13745/j.esf.sf.2021.9.14 |
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| 作者姓名： | 彭光荣 杜晓东 姜素华 李三忠 关雪婷 魏董 姜衍 陆蕾蕾 |
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| 作者单位： | 1.中海石油(中国)有限公司 深圳分公司, 广东 深圳 5180002.深海圈层与地球系统前沿科学中心/海底科学与探测技术教育部重点实验室/中国海洋大学 海洋地球科学学院, 山东 青岛 2661003.青岛海洋科学与技术国家实验室 海洋矿产资源评价与探测技术功能实验室, 山东 青岛 266100 |
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| 基金项目： | 中海石油(中国)有限公司深圳分公司科研项目(SCKY-2020-SZ-15);国家自然科学基金项目(41976054);国家自然科学基金项目(91958214);泰山学者计划(ts20190918);青岛市创新领军人才计划(19-3-2-19-zhc) |
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| 摘 要： | 近海盆地烃源岩评价是海上油气勘探成败的关键,也是亟待解决的关键科学问题。珠江口盆地阳江凹陷近期实现了油气勘探的重大突破,并展示了该区广阔的勘探前景。但在海上探井井位不足的情况下,仅靠地震资料难以客观地评价烃源岩的生烃潜力。为了进一步明确该区主要生烃层文昌组的生烃潜力,本文首先利用最新的四维层序地层模拟(Bandlands软件)技术,恢复了阳江凹陷古近系沉积期间的古地貌。古地貌恢复预测的古环境特征较好地揭示了文昌组古地貌与沉积体系的对应关系,说明文昌组古地貌背景对烃源岩沉积发育的影响较大。结合沉积体系的研究结果,分析总结了该区文昌组沉积时的源-汇特征,表明该凹陷文昌组早期是烃源岩发育的最有利时期。再结合洼陷古地貌特征、烃源岩的发育程度(主要依据半深湖相的厚度和面积)、与油源断裂的沟通及浅部圈闭的匹配等将各洼陷烃源岩综合划分为优质烃源岩、较好烃源岩和一般烃源岩3个级别:恩平20洼、恩平21洼为优质烃源岩;恩平27洼为较好烃源岩;恩平19洼、阳江24洼等为一般烃源岩。在对烃源岩分布预测的基础上,根据已钻井烃源岩样品的分析化验资料,将实验分析、地质分析与模拟结果相结合,分别对文昌组上段和文昌组下段两套烃源岩的沉积埋藏史、热演化史及生烃史进行综合分析。最后利用Petromod盆地模拟技术模拟了文昌组烃源岩的生烃潜力。模拟结果表明:恩平20、21洼和恩平27洼文昌组下段烃源岩生烃强度大于文昌组上段烃源岩生烃强度,说明文昌组下段烃源岩为生烃潜力最好的层段,且凹陷中东部的恩平20、21洼和南部的恩平27洼为生烃潜力最好的洼陷,具有较好的勘探潜力。这种基于古地貌和源-汇特征分析的烃源岩评价,对近海油气勘探具有重要的指导作用。
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| 关 键 词： | 阳江凹陷 源-汇特征 四维层序地层模拟 盆地模拟 烃源岩评价 |
| 收稿时间： | 2020-06-16 |
Source rock evaluation based on paleotopographic and source-to-sink analysis: An example of the Yangjiang Sag,Pearl River Mouth Basin |
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| PENG Guangrong,DU Xiaodong,JIANG Suhua,LI Sanzhong,GUAN Xueting,WEI Dong,JIANG Yan,LU Leilei. Source rock evaluation based on paleotopographic and source-to-sink analysis: An example of the Yangjiang Sag,Pearl River Mouth Basin[J]. Earth Science Frontiers, 2022, 29(5): 188-202. DOI: 10.13745/j.esf.sf.2021.9.14 |
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| Authors: | PENG Guangrong DU Xiaodong JIANG Suhua LI Sanzhong GUAN Xueting WEI Dong JIANG Yan LU Leilei |
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| Affiliation: | 1. Shenzhen Branch, CNOOC China Limited, Shenzhen 518000, China2. Frontiers Science Center for Deep Ocean Multispheres and Earth System/MOE Key Lab of Submarine Geosciences and Prospecting Techniques/College of Marine Geosciences, Ocean University of China, Qingdao 266100, China3. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266100, China |
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| Abstract: | Source rock evaluation in offshore basins is crucial to the success of marine oil and gas exploration and also a key scientific problem to be solved urgently. Recently, a great breakthrough has been made in the Yangjiang Sag, Pearl River Mouth Basin revealing its excellent exploration potential in marine oil and gas. However, it is difficult to objectively evaluate the hydrocarbon generation potential of source rocks by seismic data alone when there are few exploratory wells in the study area. In order to determine the hydrocarbon generation potential of the Wenchang Formation-the primary hydrocarbon generating layer of the Yangjiang Sag, 4-dimensional sequence-stratigraphic simulation (Bandlands) is conducted to reconstruct the paleo-topography of the Yangjiang Sag during the Paleogene. The predicted paleoenvironmental characteristics better reveal the corresponding relationship between the paleo-topography and the sedimentary systems of the Wenchang Formation, and demonstrate the paleotopographic background of the Wenchang Formation has important impacts on the sedimentary development of source rocks. According to the analysis of sedimentary systems, the source-to-sink characteristics of the Wenchang Formation are summarized, which show that the sedimentary period of the Lower Wenchang Formation is the most favorable period for the source rock development. Combined with the paleo-topographic features, degree of source rock development (mainly the thickness and area of semi-deep lacustrine facies), connection status between source rocks and oil-source faults, and match between source rocks and shallow traps, the source rocks in each subsag are divided into three categories: high-quality source rocks (Enping sag 20, 21), relatively good source rocks (Enping subsag 27), and general source rocks (Enping subsag 19, Yangjiang subsag 24). On the basis of source rock distribution prediction and core analysis, combined with geological data and paleotopographic simulation results, the sedimentary burial history, thermal history and hydrocarbon generation history of source rocks in the Lower and Upper Wenchang Formations are analyzed, and the hydrocarbon generation potential of source rocks in the Wenchang Formation are simulated using PetroMod. The simulation results show that the source socks of the Lower Wenchang Formation has greater hydrocarbon generation strength than the Upper Wenchang Formation in the Enping subsag 20, 21, 27, indicating the Lower Wenchang Formation layer has the best hydrocarbon generation potential of source rocks, and the eastern and southern Yangjiang Sag (Enping subsag 20, 21, 27) have the best exploration potential. Source rock evaluation based on peleo-topographic analysis and source-to-sink characteristics is very important for guiding marine oil and gas exploration. |
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| Keywords: | Yangjiang Sag source-to-sink characteristics 4-dimensional sequence-stratigraphic simulation basin simulation source rocks evaluation |
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