Distribution of sedimentary system multi-controlled by palaeo-geomorphology, water system and break during the deposition of Pinghu Formation, Baochu slope belt, Xihu Sag, East China Sea Shelf Basin
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摘要: 西湖凹陷是我国东海陆架盆地油气勘探的主战场,同时也具有巨大的勘探潜力。已有很多研究认为西湖凹陷始新统平湖组是潮坪沉积为主的海—陆过渡体系,其物源主要来自西部和北部凸起区。然而关于砂体从物源区到汇聚区的“源—渠—汇”过程目前研究较为缺乏,并且对“源—渠—汇”体系发育的制约因素探讨不够深入。该文以西湖凹陷保俶斜坡带平湖组为主要研究对象,利用钻井、地震等资料开展高精度古地貌恢复,并在古地貌基础上对古水系、古坡折进行定性与定量分析。研究表明,古地貌控制了沉积汇聚区的位置,古水系约束了输砂通道的分布,古坡折控制了沉积相带的空间配置;“古地貌—古水系—古坡折”3个因素联合约束了砂体从物源区通过河流输运在汇聚区沉积的全过程,进而控制着整个保俶斜坡带沉积体系的展布。Abstract: The Xihu Sag has huge exploration potential and is the main target for oil and gas exploration in the East China Sea Shelf Basin. At present, it has been known that the Xihu Sag has a transitional facies with sedimentary system mainly composed of tidal flat deposits, and the provenance of which is dominated by western and northern uplift area. However, the transport process of sands from source area to deposit area, namely "source-channel-sink" system, has not been well studied. In this study, we take the Pinghu Formation of Baochu slope belt in the Xihu Sag as research object, and use borehole and seismic data to preform high-precision restoration of palaeo-geomorphology. Moreover, on the basis of palaeo-geomorphology restoration, we make qualitative and quantitative analyses of palaeo-water-system and palaeo-break. Results show that the location of sink zone is controlled by palaeo-geomorphology, the distribution of sand transporting channel is controlled by palaeo-water-system, and the development of sedimentary facies is controlled by palaeo-break. Through comprehensive analysis, we suppose that the combination of "palaeo-geomorphology, palaeo-water-system and palaeo-break" restricts the process of sand body deposition from provenance to convergence area through river transportation, and controls the distribution of the sedimentary system of Baochu slope belt.
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Key words:
- palaeo-geomorphology /
- source-channel-sink /
- sedimentary system /
- Pinghu Formation /
- Eocene /
- Xihu Sag /
- East China Sea Shelf Basin
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表 1 东海西湖凹陷保俶斜坡带宝石组底界沉积时期地貌坡折定量数据
Table 1. Quantitative data of geomorphic slope break when the bottom of Baoshi Formation deposited, Baochu slope belt, Xihu Sag, East China Sea Shelf Basin
T40界面坡折参数 木广迎构造带 平湖构造带 初阳构造带 多断型坡折 垒堑型坡折 转换带型坡折 单断型坡折 多断型坡折 单断型坡折 坡折位置 高位 低位 高位 低位 高位 低位 高位 低位 高位 低位 高位 低位 平均坡角/(°) 7.0 16.7 4.0 15.6 8.9 25.3 25.8 8.7 19.5 3.1 26.9 坡长区间 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 坡长/km 19.4 19.5 19.1 10.2 10.7 26.3 2.1 9.5 17.5 2.3 2.0 总坡长/km 38.9 29.3 37.0 2.1 27.0 4.3 注:高位—低位表示高位坡折点到低位坡折点;低位—盆底表示低位坡折点到盆地底部。下面表格相同。 表 2 东海西湖凹陷保俶斜坡带平湖组下段底界沉积时期地貌坡折定量数据
Table 2. Quantitative data of geomorphic slope break when the bottom of the lower section of Pinghu Formation deposited, Baochu slope belt, Xihu Sag, East China Sea Shelf Basin
T34界面坡折参数 木广迎构造带 平湖构造带 初阳构造带 多断型坡折 垒堑型坡折 转换带型坡折 单断型坡折 多断型坡折 单断型坡折 坡折位置 高位 低位 高位 低位 高位 低位 高位 低位 高位 低位 高位 低位 平均坡角/(°) 0.8 0.2 7.9 7.5 10.3 0.4 10.8 0.3 10.3 3.3 11.0 坡长区间 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 坡长/km 22.2 19.4 4.5 9.3 14.3 0.5 9.0 8.3 14.3 7.9 2.5 总坡长/km 23.9 23.6 9.5 22.6 10.4 表 3 东海西湖凹陷保俶斜坡带平湖组中段底界沉积时期地貌坡折定量数据
Table 3. Quantitative data of geomorphic slope break when the bottom of the middle section of Pinghu Formation deposited, Baochu slope belt, Xihu Sag, East China Sea Shelf Basin
T32界面坡折参数 木广迎构造带 平湖构造带 初阳构造带 多斜坡型坡折 缓坡型坡折 挠曲—陡坡型坡折 多斜坡型坡折 挠曲—陡坡型坡折 坡折位置 高位 低位 高位 低位 高位 低位 高位 低位 高位 低位 平均坡角/(°) 1.9 3.6 3.2 4.8 7.3 1.5 4.8 1.6 10.6 坡长区间 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 高位—低位 低位—盆底 坡长/km 8.6 7.0 32.0 4.0 7.8 7.8 14.3 11.8 10.9 总坡长/km 15.6 32.0 11.8 22.1 22.7 -
[1] 秦伟军, 张中华. 中国东部断陷盆地油气勘探开发现状及技术需求[J]. 石油科技论坛, 2015, 34(6): 42-45. https://www.cnki.com.cn/Article/CJFDTOTAL-SYKT201506009.htmQIN Weijun, ZHANG Zhonghua. Present conditions and technolo-gical demand of oil and gas exploration and development in China's eastern faulted basins[J]. Oil Forum, 2015, 34(6): 42-45. https://www.cnki.com.cn/Article/CJFDTOTAL-SYKT201506009.htm [2] 杜学斌, 陆永潮, 曹强, 等. 东海盆地西湖凹陷深部储层"相—岩—温"三元分级评价原则与效果[J]. 地质科技通报, 2020, 39(3): 10-19. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003005.htmDU Xuebin, LU Yongchao, CAO Qiang, et al. Grading evaluation of deep reservoir in Xihu Depression, East China Sea Basin[J]. Bulletin of Geological Science and Technology, 2020, 39(3): 10-19. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003005.htm [3] 高伟中. 西湖凹陷中央反转带中北部天然气高效成藏主控因素及富集规律[J]. 地质科技通报, 2020, 39(3): 40-48. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003008.htmGAO Weizhong. Major controlling factors and enrichment rules of highly efficient gas reservoiring in the north-central part of the central inversion belt, Xihu Depression[J]. Bulletin of Geological Science and Technology, 2020, 39(3): 40-48. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003008.htm [4] 赵丽娜. 东海陆架盆地西湖凹陷平湖构造带沉积相研究[D]. 长春: 吉林大学, 2007.ZHAO Lina. The study on sedimentary facies of Pinghu Zone in Xihu Sag in the East China Sea Shelf Basin[D]. Changchun: Jilin University, 2007. [5] 田杨, 叶加仁, 雷闯, 等. 断陷盆地海陆过渡相烃源岩发育模式: 以西湖凹陷平湖组为例[J]. 地球科学, 2019, 44(3): 898-908. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201903017.htmTIAN Yang, YE Jiaren, LEI Chuang, et al. Development model for source rock of marine-continental transitional face in Faulted Basins: A case study of Pinghu Formation in Xihu Sag[J]. Earth Science, 2019, 44(3): 898-908. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201903017.htm [6] 王泽宇, 徐清海, 侯国伟, 等. 东海陆架盆地西湖凹陷W井区平湖组潮汐沉积模式[J]. 海相油气地质, 2021, 26(2): 159-169. https://www.cnki.com.cn/Article/CJFDTOTAL-HXYQ202102008.htmWANG Zeyu, XU Qinghai, HOU Guowei, et al. Tidal depositional model of Pinghu Formation in W well block of Xihu Sag, East China Sea Shelf Basin[J]. Marine Origin Petroleum Geology, 2021, 26(2): 159-169. https://www.cnki.com.cn/Article/CJFDTOTAL-HXYQ202102008.htm [7] 常吟善, 段冬平, 张兰, 等. 西湖凹陷平湖斜坡带A气田沉积体系定量表征及海平面变化周期性探讨[J]. 海洋地质与第四纪地质, 2021, 41(3): 12-21. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDZ202103002.htmCHANG Yinshan, DUAN Dongping, ZHANG Lan, et al. Quantitative characterization of the depositional system in Gas field A, Pinghu slope belt, Xihu Sag and its bearing on periodicity of sea level changes[J]. Marine Geology & Quaternary Geology, 2021, 41(3): 12-21. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDZ202103002.htm [8] 张功成, 米立军, 吴景富, 等. 凸起及其倾没端—琼东南盆地深水区大中型油气田有利勘探方向[J]. 中国海上油气, 2010, 22(6): 360-368. https://www.cnki.com.cn/Article/CJFDTOTAL-ZHSD201006003.htmZHANG Gongcheng, MI Lijun, WU Jingfu, et al. Rises and their plunges: favorable exploration directions for major fields in the deepwater area, Qiongdongnan basin[J]. China Offshore Oil and Gas, 2010, 22(6): 360-368. https://www.cnki.com.cn/Article/CJFDTOTAL-ZHSD201006003.htm [9] 傅宁, 米立军, 张功成. 珠江口盆地白云凹陷烃源岩及北部油气成因[J]. 石油学报, 2007, 28(3): 32-38. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB200703006.htmFU Ning, MI Lijun, ZHANG Gongcheng. Source rocks and origin of oil and gas in the northern Baiyun Depression of Pearl River Mouth Basin[J]. Acta Petrolei Sinica, 2007, 28(3): 32-38. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB200703006.htm [10] 傅宁, 邓运华, 张功成, 等. 南海北部叠合断陷盆地海陆过渡相烃源岩及成藏贡献: 以珠二坳陷白云凹陷为例[J]. 石油学报, 2010, 31(4): 559-565. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB201004006.htmFU Ning, DENG Yunhua, ZHANG Gongcheng, et al. Transitional source rock and its contribution to hydrocarbon accumulation in superimpose rift-subsidence basin of northern South China Sea: Taking Baiyun Sag of Zhu Ⅱ Depression as an example[J]. Acta Petrolei Sinica, 2010, 31(4): 559-565. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB201004006.htm [11] 刘思琦, 张昌民, 朱锐, 等. 东海陆架盆地西湖凹陷平湖组潮汐韵律与潮汐周期分析[J]. 中南大学学报(自然科学版), 2021, 52(10): 3703-3716. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202110032.htmLIU Siqi, ZHANG Changmin, ZHU Rui, et al. Analysis of tidal rhythmites and tidal cycle of Pinghu Formation in Xihu Sag, East China Sea Shelf Basin[J]. Journal of Central South University (Science and Technology), 2021, 52(10): 3703-3716. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202110032.htm [12] 蒋一鸣. 西湖凹陷平湖斜坡带平湖组碎屑锆石U-Pb年龄及米兰科维奇旋回: 对源—汇系统及沉积演化的约束[J]. 地质科技情报, 2019, 38(6): 133-140. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906016.htmJIANG Yiming. Detrital zircon U-Pb age and milankovitch cycles of Pinghu Formation in the Pinghu Slope of Xihu Depression: Constraints on source-sink system and sedimentary evolution[J]. Geological Science and Technology Information, 2019, 38(6): 133-140. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906016.htm [13] 刘金水, 陆永潮, 秦兰芝. 源—汇系统分析方法在大型储集体研究中的应用: 以西湖凹陷中央反转带花港组为例[J]. 石油实验地质, 2019, 41(3): 303-310. doi: 10.11781/sysydz201903303LIU Jinshui, LU Yongchao, QIN Lanzhi. Application of source to sink system analysis in large reservoir research: a case study of Huagang Formation, Central Inversion Belt, Xihu Depression[J]. Petroleum Geology & Experiment, 2019, 41(3): 303-310. doi: 10.11781/sysydz201903303 [14] 赵珂, 杜学斌, 贾冀新, 等. 西湖凹陷平湖斜坡带的物源分析: 来自碎屑锆石U-Pb年代学及重矿物的证据[J]. 地质科技通报, 2020, 39(3): 68-76. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003011.htmZHAO Ke, DU Xuebin, JIA Jixin, et al. Provenance analysis of the Pinghu slope belt in Xihu Depression: Evidence from detrital zircon U-Pb chronology and heavy minerals[J]. Bulletin of Geological Science and Technology, 2020, 39(3): 68-76. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202003011.htm [15] 何昕锴, 李晓龙, 赵洪, 等. 东海西湖凹陷碎屑岩物源聚类分析[J]. 海洋地质前沿, 2020, 36(6): 11-19. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDT202006002.htmHE Xinkai, LI Xiaolong, ZHAO Hong, et al. Clustering analysis of clastic rocks for provenance in Xihu depression[J]. Marine Geology Frontiers, 2020, 36(6): 11-19. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDT202006002.htm [16] WANG Wenguang, LIN Chengyan, ZHANG Xianguo, et al. Provenance, clastic composition and their impact on diagenesis: A case study of the Oligocene sandstone in the Xihu sag, East China Sea Basin[J]. Marine and Petroleum Geology, 2021, 126: 104890. [17] ZHANG Jingyu, PAS D, KRIJGSMAN W, et al. Astronomical forcing of the Paleogene coal-bearing hydrocarbon source rocks of the East China Sea Shelf Basin[J]. Sedimentary Geology, 2020, 406: 105715. [18] 吴正韩. 中国东海陆架盆地西湖凹陷生物地层初探[J]. 地层学杂志, 2014, 38(4): 470-478. https://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ201404012.htmWU Zhenghan. Cenozoic biostratigraphy of the Xihu Sag, northeast continental shelf basin of the east China sea[J]. Journal of Stratigraphy, 2014, 38(4): 470-478. https://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ201404012.htm -