北部湾盆地低勘探程度凹陷烃源岩发育规律评价与潜力比选

Evaluation of hydrocarbon source rock development pattern and potential comparison of low exploration degree sags in Beibu Gulf Basin

摘要

针对北部湾盆地低勘探程度凹陷钻井资料少、潜力比选难度大等问题,通过对烃源岩形成期构造、沉积特征的精细解析和定量/半定量表征,提出以“构造三速率、沉积三单元”评价为关键、以富烃凹陷类比为参考的低勘探程度凹陷烃源岩评价思路与方法,对北部湾盆地低勘探程度凹陷烃源岩发育规律进行系统评价与潜力比选。结果表明:北部湾盆地流二段烃源岩形成期主要为NE向断裂控凹,伸展构造样式发育为主,单断式半地堑或双断式地堑结构;断层活动速率、水平伸展速率、基底沉降速率共同控制凹陷结构与沉积充填;流二段烃源岩形成期低勘探程度凹陷和主力富烃凹陷以及不同低勘探程度凹陷之间的物源区母岩类型与隆升速率、搬运过程中的砂分散体系和“沉砂池”位置、半深湖-深湖规模、古水深、古氧化还原性、“源/汇”比等存在差异,明确海中凹陷东洼、迈陈凹陷东洼2个有利的低勘探程度凹陷。

Abstract

To address the challenges of limited drilling data and the difficulty of evaluating exploration potential in low-exploration sags of the Beibu Gulf Basin, this study systematically assesses and compares the potential of such sags through detailed analysis and quantitative/semi-quantitative characterization of structural and depositional features during the hydrocarbon source rock formation period. A systematic evaluation methodology, termed the "tectonic three-rate and sedimentary three-unit" approach, was established using hydrocarbon-rich sags as analogs to assess the distribution patterns and exploration potential of source rocks in low-exploration sags within the Beibu Gulf Basin. The results indicate that during the deposition of the source rocks of the second member of the Liushagang Formation, the Beibu Gulf Basin was primarilly controlled by NE-trending faults, resulting in extensional tectonic styles and the development of single-fault half graben or double-fault graben sag structures. The rate of fault activity, horizontal extension rate, and basement subsidence rate jointly controlled the structural framework and sedimentary infill of the sags. Significant differences are observed among the sags in terms of parent rock type and uplift rate, sediment dispersal systems and the locations of "grit chambers" during sediment transport, the scale of semi-deep to deep lacustrine environments, paleowater depth, paleo-oxidation conditions, and source-to-sink ratios during source rock deposition. Based on the comprehensive evaluation, two highly prospective subsags, the eastern subsag of the Haizhong sag and the eastern subsag of the Maichen sag, are identified as favorable exploration targets.

关键词

烃源岩 / 构造特征 / 沉积作用 / 潜力比选 / 北部湾盆地

Key words

source rock / structural feature / sedimentary effect / exploration potential comparison / Beibu Gulf Basin

参考文献

[1] 于水, 邓运华, 李宏义, 等 . 北部湾盆地流二段油页岩形成条件与分布控制因素[J]. 中国海上油气, 2020, 32(2): 24-33.

[2] YU Shui, DENG Yunhua, LI Hongyi, et al. Forming conditions and distribution controlling factors of oil shale in Liu2 member of Beibuwan Basin[J]. China Offshore Oil and Gas, 2020, 32(2): 24-33.

[3] 李友川, 兰蕾, 王柯, 等 . 北部湾盆地流沙港组湖相烃源岩的差异[J]. 石油学报, 2019, 40(12): 1451-1459.

[4] LI Youchuan, LAN Lei, WANG Ke, et al. Differences in lacustrine source rocks of Liushagang Formation in the Beibuwan Basin[J]. Acta Petrolei Sinica, 2019, 40(12): 1451-1459.

[5] 刘池洋, 赵俊峰, 马艳萍, 等 . 富烃凹陷特征及其形成研究现状与问题[J]. 地学前缘, 2014, 21(1): 75-88.

[6] LIU Chiyang, ZHAO Junfeng, MA Yanping, et al. The advances and problems in the study of the characteristics and formation of hydrocarbon-rich sag[J]. Earth Science Frontiers, 2014, 21(1): 75-88.

[7] 米立军, 张功成, 刘志峰, 等 . 中国近海富油凹陷湖相优质烃源岩发育机制[J]. 石油学报, 2023, 44(3): 405-419,509.

[8] MI Lijun, ZHANG Gongcheng, LIU Zhifeng, et al. Discussion on the development mechanism of lacustrine high-quality source rocks in oil-rich sags in offshore China[J]. Acta Petrolei Sinica, 2023, 44(3): 405-419,509.

[9] 韩豫, 操应长, 梁超, 等 . 川南地区五峰组-龙马溪组沉积环境演化及其对页岩发育的控制[J]. 中国石油大学学报(自然科学版), 2024, 48(2): 11-23.

[10] HAN Yu, CAO Yingchang, LIANG Chao, et al. Sedimentary environment evolution of Wufeng Formation-Longmaxi Formation and its control on shale deposition in the southern Sichuan Basin[J]. Journal of China University of Petroleum (Edition of Natural Science), 2024, 48(2): 11-23.

[11] 王勇. 济阳坳陷古近系沙三下-沙四上亚段咸化湖盆证据及页岩油气地质意义[J]. 中国石油大学学报(自然科学版), 2024, 48(3): 27-36.

[12] WANG Yong. Evidence of Paleogene saline lake basin in the 3rd and 4th members of Shahejie Formation in Jiyang Depression and geological significance of shale oil and gas[J]. Journal of China University of Petroleum (Edition of Natural Science), 2024, 48(3): 27-36.

[13] 姚玉来, 肖飞, 李士超, 等 . 松辽盆地齐家凹陷南部青山口组一段古环境及其对有机质富集的控制作用[J]. 中国石油大学学报(自然科学版), 2025, 49(1): 59-71.

[14] YAO Yulai, XIAO Fei, LI Shichao, et al. Paleoenvironment of the first member of Qingshankou Formation in southern Qijia Sag, Songliao Basin and its control on enrichment of organic matter[J]. Journal of China University of Petroleum (Edition of Natural Science), 2025, 49(1): 59-71.

[15] LI Wei, CAO Mingyue, WANG Di, et al. Cenozoic structure of the Zhu3 Depression in the Pearl River Mouth Basin and its response to the dynamic background of the South China Sea[J]. Journal of the Geological Society, 2024, 181(4): 1-13.

[16] 卢林, 汪企浩, 黄建军. 北部湾盆地涠西南和海中凹陷新生代局部构造演化史[J]. 海洋石油, 2007, 27(1): 25-29,57.

[17] LU Lin, WANG Qihao, HUANG Jianjun. Structural evolvement history of Weixinan and Haizhong depression in Beibuwan basin during Cenozoic Era[J]. Offshore Oil, 2007, 27(1): 25-29,57.

[18] LI Wei, CAO Mingyue, MENG Meifang, et al. Characteristics of transfer zones under the influence of pre-existing faults and regional stress transformation: Wenchang A subsag, Zhujiang River Mouth Basin, northern South China Sea[J]. Journal of Oceanology and Limnology, 2024, 42(3): 744-759.

[19] 张佰涛, 唐金炎, 王文军, 等 . 北部湾盆地北部坳陷构造:沉积特征及其演化[J]. 海洋石油, 2014, 34(2): 7-12.

[20] ZHANG Baitao, TANG Jinyan, WANG Wenjun, et al. Characteristics of tectonic sedimentary evolution in northern depression of Beibuwan Basin[J]. Offshore Oil, 2014, 34(2): 7-12.

[21] 李春荣, 张功成, 梁建设, 等 . 北部湾盆地断裂构造特征及其对油气的控制作用[J]. 石油学报, 2012, 33(2): 195-203.

[22] LI Chunrong, ZHANG Gongcheng, LIANG Jianshe, et al. Characteristics of fault structure and its control on hydrocarbons in the Beibuwan Basin[J]. Acta Petrolei Sinica, 2012, 33(2): 195-203.

[23] 张智武, 刘志峰, 张功成, 等 . 北部湾盆地裂陷期构造及演化特征[J]. 石油天然气学报, 2013, 35(1): 6-10,172.

[24] ZHANG Zhiwu, LIU Zhifeng, ZHANG Gongcheng, et al. The chasmic stage and structural evolution features of Beibuwan Basin[J]. Journal of Oil and Gas Technology, 2013, 35(1): 6-10, 172.

[25] 杨希冰. 南海北部北部湾盆地油气藏形成条件[J]. 中国石油勘探, 2016, 21(4): 85-92.

[26] YANG Xibing. Hydrocarbon accumulation conditions in Beibu-gulf Basin, northern South China Sea[J]. China Petroleum Exploration, 2016, 21(4): 85-92.

[27] 姜雪, 吴克强, 刘丽芳, 等 . 构造活动对富生油凹陷烃源岩的定量控制:以中国近海古近系为例[J]. 石油学报, 2014, 35(3): 455-461.

[28] JIANG Xue, WU Keqiang, LIU Lifang, et al. Quantitative control of tectonic activity for source rocks in rich oil kitchen sags: a case study of Paleogene in China offshore[J]. Acta Petrolei Sinica, 2014, 35(3): 455-461.

[29] 林畅松, 夏庆龙, 施和生, 等 . 地貌演化、源-汇过程与盆地分析[J]. 地学前缘, 2015, 22(1): 9-20.

[30] LIN Changsong, XIA Qinglong, SHI Hesheng, et al. Geomorphological evolution, source to sink system and basin analysis[J]. Earth Science Frontiers, 2015, 22(1): 9-20.

[31] BENTLEY S J, BLUM M D, MALONEY J, et al. The Mississippi River source-to-sink system: perspectives on tectonic, climatic, and anthropogenic influences, Miocene to Anthropocene[J]. Earth-Science Reviews, 2016, 153: 139-174.

[32] WALSH J P, WIBERG P L, AALTO R, et al. Source-to-sink research: economy of the Earth̍s surface and its strata[J]. Earth-Science Reviews, 2016, 153: 1-6.

[33] 徐长贵, 杜晓峰, 徐伟, 等 . 沉积盆地“源-汇”系统研究新进展[J]. 石油与天然气地质, 2017, 38(1): 1-11.

[34] XU Changgui, DU Xiaofeng, XU Wei, et al. New advances of the "Source-to-Sink" system research in sedimentary basin[J]. Oil & Gas Geology, 2017, 38(1): 1-11.

[35] 彭光荣, 杜晓东, 姜素华, 等 . 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.

[36] PENG Guangrong, DU Xiaodong, JIANG Suhua, et al. 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.

[37] ALLEN P A, ARMITAGE J J, CARTER A, et al. The Q_s problem: sediment volumetric balance of proximal foreland basin systems [J]. Sedimentology, 2013, 60(1): 102-130.

[38] SØMME T O, HELLAND-HANSEN W, MARTINSEN O J, et al. Relationships between morphological and sedimentological parameters in source-to-sink systems: a basis for predicting semi-quantitative characteristics in subsurface systems[J]. Basin Research, 2009, 21(4): 361-387.

[39] 曹磊. 北部湾盆地流二段烃源岩的有机质富集机理及发育模式[D]. 北京: 中国石油大学(北京), 2021.

[40] CAO Lei. Organic matter enrichment mechanism and development model of source rocks in the 2nd member of Liushagang Formation in Beibuwan Basin[D]. Beijing: China University of Petroleum (Beijing), 2021.

[41] 舒梁锋, 张丽丽, 雷胜兰, 等 . 南海北部白云南洼陆架坡折带演化特征及其控制因素[J]. 石油地球物理勘探, 2022, 57(3): 686-696,495-496.

[42] SHU Liangfeng, ZHANG Lili, LEI Shenglan, et al. Evolution characteristics and controlling factors of shelf break zone in south subsag of Baiyun Sag in northern South China Sea[J]. Oil Geophysical Prospecting, 2022, 57(3): 686-696,495-496.

[43] 赵斌, 王利杰, 张宝金, 等 . 南海东部次海盆南侧基底结构与沉积特征及其控制因素[J]. 大地构造与成矿学, 2022, 46(5): 884-897.

[44] ZHAO Bin, WANG Lijie, ZHANG Baojin, et al. Basement and sedimentary characteristics and controlling factors of the southern east sub-basin, South China Sea[J]. Geotectonica et Metallogenia, 2022, 46(5): 884-897.

[45] 汤智逸, 解习农, 徐俊杰, 等 . 曾母盆地古拉让三角洲发育演化定量表征及其控制因素分析[J]. 西南石油大学学报(自然科学版), 2025, 47(1): 147-162.

[46] TANG Zhiyi, XIE Xinong, XU Junjie, et al. Quantitative characterization of evolution and controlling factors of paleo-rajang delta in the Zengmu Basin[J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2025, 47(1): 147-162.

[47] COVAULT J A, ROMANS B W, GRAHAM S A, et al. Terrestrial source to deep-sea sink sediment budgets at high and low sea levels: insights from tectonically active Southern California[J]. Geology, 2011, 39(7): 619-622.

[48] 张功成, 封从军, 陈莹, 等 . 南海北部陆缘渐进式裂陷控制烃源岩差异分布[J]. 中国海上油气, 2025, 37(2): 27-44.

[49] ZHANG Gongcheng, FENG Congjun, CHEN Ying, et al. Progressive rifting controls the differential distribution of source rocks in the northern continental margin of the South China Sea[J]. China Offshore Oil and Gas, 2025, 37(2): 27-44.

[50] CARROLL A R, BOHACS K M . Lake-type controls on petroleum source rock potential in nonmarine basins[J]. AAPG Bulletin, 2001, 85(6): 1033-1053.

[51] 张涛, 王琳霖, 廖慧鸿, 等 . 沉积盆地古水深恢复方法与研究进展[J]. 沉积与特提斯地质, 2024, 44(3): 582-599.

[52] ZHANG Tao, WANG Linlin, LIAO Huihong, et al. Methods and research progress of paleo-water depth reconstruction in sedimentary basins[J]. Sedimentary Geology and Tethyan Geology, 2024, 44(3): 582-599.

[53] 叶加仁, 赵牛斌, 杨宝林, 等 . 涠西南凹陷流沙港组烃源岩生产力及发育模式[J]. 地质科技通报, 2020, 39(1): 105-113.

[54] YE Jiaren, ZHAO Niubin, YANG Baolin, et al. Productivity and development model of source rock of the Liushagang Formation in the Weixinan Sag[J]. Bulletin of Geological Science and Technology, 2020, 39(1): 105-113.

基金资助

“十三五”国家科技重大专项(2016ZX05024-002)