石油学报 ›› 2022, Vol. 43 ›› Issue (10): 1427-1438,1473.DOI: 10.7623/syxb202210006

• 地质勘探 • 上一篇    下一篇

南海南部Crocker扇物源特征及油气地质意义

崔宇驰1, 赵志刚2, 邵磊1, 朱伟林1, 乔培军1, 唐武2, 李莉妮1   

  1. 1. 同济大学海洋地质国家重点实验室 上海 200092;
    2. 中海油研究总院有限责任公司 北京 100027
  • 收稿日期:2021-09-15 修回日期:2022-06-13 出版日期:2022-10-25 发布日期:2022-11-05
  • 通讯作者: 邵磊,男,1960年10月生,1996年获基尔大学理学博士学位,现为同济大学教授,主要从事海洋地质学、沉积学与地球化学科研工作。Email:lshao@tongji.edu.cn
  • 作者简介:崔宇驰,女,1991年6月生,2018年获同济大学理学硕士学位,现为同济大学博士研究生,主要从事构造沉积学研究。Email:cuiyuchi@tongji.edu.cn
  • 基金资助:
    国家科技重大计划项目(2018YFE0202400)和国家自然科学基金项目(No.42076066、No.92055203)资助。

Provenance characteristics and petroleum geological significance of Crocker fan in southern South China Sea

Cui Yuchi1, Zhao Zhigang2, Shao Lei1, Zhu Weilin1, Qiao Peijun1, Tang Wu2, Li Lini1   

  1. 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China;
    2. CNOOC Research Institute Company Limited, Beijing 100027, China
  • Received:2021-09-15 Revised:2022-06-13 Online:2022-10-25 Published:2022-11-05

摘要: 新生代南海南部发育多个大型沉积盆地,具有良好的油气成藏地质条件,蕴藏丰富的油气资源。Crocker扇是南海南部盆地中规模最大的沉积扇体,对其物质组成、物源演变和沉积充填过程认识不清严重制约了扇体油气资源的勘探与开发。基于野外露头观察、重矿物组合分析、元素地球化学特征和碎屑锆石U-Pb年龄谱系综合示踪技术,对婆罗洲地区Crocker扇的沉积物组成及其潜在物源区开展了系统的"源-汇"对比研究。结果表明,晚始新世Crocker扇以角度不整合覆盖在Rajang群之上,底部为少量底砾岩,其为岩浆岛弧近源剥蚀、搬运和沉积的产物,物源区为古南海向南俯冲形成的局部隆起。晚始新世—早中新世,Crocker扇碎屑锆石U-Pb年龄谱系表现宽广多峰的特征,可识别出明显的印支期主峰和燕山期、海西期—加里东期、晋宁期、古元古代等多个年龄次峰及少量太古代年龄低峰,扇主体沉积物源主要来自马来半岛地区。婆罗洲地区西侧的曾母盆地广泛发育三角洲平原亚相、浅海三角洲相沉积,婆罗洲地区东侧的文莱—沙巴盆地发育深水浊积扇,砂体规模大,沉积物粒度适中,具备形成优质储集体的物质基础,是南海南部油气勘探的重要目的层,具有良好的油气勘探前景。

关键词: 南海南部, Crocker扇, 物源演化, 马来半岛, 锆石U-Pb年龄谱系

Abstract: Many large sedimentary basins are developed in the southern South China Sea in Cenozoic, which have good geological conditions of oil and gas accumulation and rich oil and gas resources. The Crocker fan is the largest sedimentary fan in the basins in the southern South China Sea; the unclear understanding of its substance composition, provenance evolution and sedimentary filling process seriously restricts the exploration and development of oil and gas resources in fan bodies. Based on field outcrop observation, heavy mineral assemblage analysis, element geochemical characteristics and integrated tracer technique of clastic zircon U-Pb age spectra, a systematic comparative study of source and sink was carried out on the composition of the sediments of Crocker fan and their potential provenance in Borneo area. The results show that the late Eocene Crocker fan covers the Rajang group in angular unconformity, and there is a small amount of basal conglomerates in the bottom, being the product of near-source denudation, transportation and sedimentation of the magmatic island arc. The provenance of these conglomerates is the local uplift formed by southward subduction of the ancient South China Sea. During the Late Eocene-Early Miocene period, the Crocker fan clastic zircon U-Pb age spectra shows the characteristics of being wide and having many peaks, thus identifying the obvious Indosinian main peak and the Yanshanian, Hercynian-Caledonian, Jinningian and Paleoproterozoic minor peaks, as well as a small amount of Archaeozoic zircons mainly originated from the Malay Peninsula area. Delta plain subfacies and neritic delta facies are widely developed in Zengmu Basin in the west of Borneo area. Deep-water turbidite fan is developed in Brunei-Sabah Basin on the east side of Borneo area with large-scale sand body and moderate grain size of sediments, which provides the material base for the formation of high-quality reservoirs. It is an important target stratum for oil-gas exploration in the southern South China Sea, and has good oil-gas exploration prospects.

Key words: South China Sea, Crocker fan, provenance evolution, Malay Peninsula, zircon U-Pb age spectra

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