Characteristics of major unconformities and their control over sedimentation in rifting stage: A case from the East China Sea
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摘要:
以东海某凹陷二维地震、三维地震及钻测井等资料为基础,开展控凹断层活动定量分析,并且探讨了断陷期重要不整合面特征及其对沉积演化的控制作用。研究表明,东海某凹陷断陷沉积时期,断裂活动从剧烈到平静,地形高差从大到小,形成了3个重要不整合面:断陷幕次界面T40和T34,断陷―断坳转换面T32。由此,将断陷期划分为3期断陷幕和1期断坳幕:断陷Ⅰ幕(古新统)为构造启动期,其受控于三潭断裂和白堤断裂,分布范围局限,发育近源沉积体系;断陷Ⅱ幕(始新统宝石组)和断陷Ⅲ幕(始新统平湖组下段)为强烈断陷期,地层被断层错断严重,水深较大,西部缓坡带以受潮汐影响的三角洲、潮坪沉积为主,东部陡坡带以扇三角洲沉积为主,受断陷格局限制,扇三角洲以快速沉积、堆积厚度大、沉积范围小、相变快为主要特征;断坳幕(始新统平湖组中上段)为断陷萎缩期,地层开始向坳陷沉积转换,盆地与南部海域沟通变强且水深变浅,凹陷内部以平行岸线的潮流作用为主,发育大规模的非对称性三角洲和陆架潮汐砂脊等,储层富集,可作为有利勘探目标。此外,断陷幕发育扇三角洲等近源沉积,是岩性油气藏的有利发育区,也为深层油气勘探提供了方向。
Abstract:Based on 2D and 3D seismic data and well drilling data from a Sag in the East China Sea, through quantitative analysis of active sag-controlling faults, the characteristics of the major unconformities and their control over sedimentation in rifting stage are discussed in this paper. The study shows that during the rifting stage, fault activities changed from violent to calm, and the topographic differences changed from large to small, that resulted in three major unconformities: second-order unconformities between rifting episodes T40 and T34, second-order unconformity between rifting episode and rift-depression episode T32. Upon the facts, the rifting stage of the sag may be subdivided into 3 rifting episodes and 1 rift-depression episode. The rifting episode I of Palaeocene is the initiation time of tectonic movement, controlled by the Santan fault and the Baidi fault with limited distribution and near-source depositional systems. The rifting episodeⅡ of Baoshi Formation and the rifting episode Ⅲ of Lower Pinghu Formation are the period of intense tectonic movement. During the period, the strata were strongly dislocated by faults, the region was covered by deep water. Tidal delta and tidal flat deposits dominated the gentle slope belt in the west, and fan delta developed in the steep slope belt in the east of the basin. Restricted by rifting depression, the fan delta is characterized by high sedimentation rate, large thickness, limited depositional area and dramatic facies change. The rift-depression episode in the middle and upper stages of the Pinghu Formation represents a shrinking period, the region began to convert to a depression. Water exchange between the basin and the seas in the south was intensified, water became shallower, large-scale asymmetric deltas and tidal sand ridges were well developed. The rift-depression episode and rift episode are favorable for the formation of lithological reservoirs, and the excellent targets for deep oil and gas exploration.
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Key words:
- rifting stage /
- unconformities /
- depositional system /
- a sag of the East China Sea
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图 3 东海某凹陷典型地震剖面特征 (a和b,剖面位置见图1 AA’)及控凹断层单位生长古落差图(c)
Figure 3.
图 5 东海某凹陷T32界面上下测录井特征(位置见图1 BB’)
Figure 5.
图 7 东海某凹陷典型地质剖面沉积特征(剖面位置见图1 AA’)
Figure 7.
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[1] 贾健谊, 顾惠荣. 东海西湖凹陷含油气系统与油气资源评价[M]. 北京: 地质出版社, 2002.
JIA Jianyi, GU Huirong. Oil-Bearing Systems and Petroleum Assessment of the Xihu Sag in the East China Sea[M]. Beijing: Geological Publish House, 2002.
[2] 陶瑞明. 从西太平洋板块构造探讨东海陆架盆地形成机制和类型划分[J]. 中国海上油气(地质), 1994, 8(1):14-20
TAO Ruiming. Discussion on basin formation mechanism and basin types in East China Sea continental shelf basin based on West Pacific plate tectonics [J]. China Offshore Oil and Gas (Geology), 1994, 8(1): 14-20.
[3] 姜亮. 东海陆架盆地油气资源勘探现状及含油气远景[J]. 中国海上油气(地质), 2003, 17(1):1-5
JIANG Liang. Exploration status and perspective of petroleum resources in East China Sea shelf basin [J]. China Offshore Oil and Gas (Geology), 2003, 17(1): 1-5.
[4] 武法东, 张燕梅, 周平, 等. 东海陆架盆地第三系沉积-构造动力背景分析[J]. 现代地质, 1999, 13(2):157-161
WU Fadong, ZHANG Yanmei, ZHOU Ping, et al. Tertiary basin setting analysis and sedimentary dynamics of the East China Sea shelf basin [J]. Geoscience, 1999, 13(2): 157-161.
[5] 胡惠娟. 东海平湖构造带地质构造特征及含油气条件[J]. 海洋石油, 2003, 23(1):1-7 doi: 10.3969/j.issn.1008-2336.2003.01.001
HU Huijuan. Geological features and hydrocarbon-bearing condition of the Pinghu tectonic belt, the East China Sea [J]. Offshore Oil, 2003, 23(1): 1-7. doi: 10.3969/j.issn.1008-2336.2003.01.001
[6] 刘景彦, 林畅松, 肖建新, 等. 东海西湖凹陷第三系主要不整合面的特征、剥蚀量的分布及其意义[J]. 现代地质, 1999, 13(4):432-438
LIU Jingyan, LIN Changsong, XIAO Jianxin, et al. Characteristics and erosions of the major tertiary unconformities and their significance to petroleum exploration in the Xihu trough, the East China Sea [J]. Geoscience, 1999, 13(4): 432-438.
[7] 李上卿. 东海西湖凹陷新生代地质构造特征与演化[J]. 海洋石油, 2000, 20(2):8-14
LI Shangqing. Cenozoic basin geological tectonic feature and evolution in Xihu trough, the East China Sea [J]. Offshore Oil, 2000, 20(2): 8-14.
[8] 宋小勇, 储呈林, 芮志峰. 东海盆地西湖凹陷构造样式及其演化[J]. 高校地质学报, 2010, 16(1):86-93 doi: 10.3969/j.issn.1006-7493.2010.01.013
SONG Xiaoyong, CHU Chenlin, RUI Zhifeng. Structural framework and evolution of Xihu Sag in East China Sea Basin [J]. Geological Journal of China Universities, 2010, 16(1): 86-93. doi: 10.3969/j.issn.1006-7493.2010.01.013
[9] 顾惠荣, 贾健谊, 叶加仁. 东海西湖凹陷含油气系统特征[J]. 石油与天然气地质, 2002, 23(3):295-297, 306 doi: 10.3321/j.issn:0253-9985.2002.03.021
GU Huirong, JIA Jianyi, YE Jiaren. Characteristics of oil and gas bearing system in Xihu lake depression in the East China Sea [J]. Oil & Gas Geology, 2002, 23(3): 295-297, 306. doi: 10.3321/j.issn:0253-9985.2002.03.021
[10] 须雪豪, 陈琳琳, 汪企浩. 东海陆架盆地中生界地质特征与油气资源潜力浅析[J]. 海洋石油, 2004, 24(3):1-7 doi: 10.3969/j.issn.1008-2336.2004.03.001
XU Xuehao, CHEN Linlin, WANG Qihao. Analysis of mesozoic geological characteristics and resource potential in the East China Sea shelf basin [J]. Offshore Oil, 2004, 24(3): 1-7. doi: 10.3969/j.issn.1008-2336.2004.03.001
[11] 余朝丰, 陈建文, 杜远生, 等. 东海西湖凹陷平湖组层序地层划分[J]. 海洋地质与第四纪地质, 2007, 27(5):85-90
YU Chaofeng, CHEN Jianwen, DU Yuansheng, et al. Division of sequence stratigraphy of Pinghu Formation in Xihu Sag in East China Sea [J]. Marine Geology and Quaternary Geology, 2007, 27(5): 85-90.
[12] 李纯洁, 张清胜, 孟其林. 东海宝石一井第三纪地层层序及沉积环境浅析[J]. 海洋石油, 2002, 22(4):14-23 doi: 10.3969/j.issn.1008-2336.2002.04.003
LI Chunjie, ZHANG Qingsheng, MENG Qilin. Preliminary research of stratigraphic sequence and paleosedimentary environments of tertiary system of Baoshi - 1 well in the East China Sea [J]. Offshore Oil, 2002, 22(4): 14-23. doi: 10.3969/j.issn.1008-2336.2002.04.003
[13] 李纯洁, 李上卿, 许红. 西湖凹陷中-下始新统宝石组油气地质与勘探潜力[J]. 海洋地质与第四纪地质, 2004, 24(4):81-87
LI Chunjie, LI Shangqing, XU Hong. Petroleum geologic characteristics and exploration potential of Middle-Lower Eocene Baoshi Formation in the Xihu Sag [J]. Marine Geology and Quaternary Geology, 2004, 24(4): 81-87.
[14] 何将启, 杨风丽. 东海西湖凹陷新生代盆地原型分析[J]. 海洋石油, 2003, 23(S1):13-20
HE Jiangqi, YANG Fengli. Prototype basin analysis in Cenozoic for Xihu Sag, East China Sea [J]. Offshore Oil, 2003, 23(S1): 13-20.
[15] 林畅松, 张燕梅, 李思田, 等. 中国东部中新生代断陷盆地幕式裂陷过程的动力学响应和模拟模型[J]. 地球科学, 2004, 29(5):583-588
LIN Changsong, ZHANG Yanmei, LI Sitian, et al. Episodic rifting dynamic process and quantitative model of Mesozoic-Cenozoic faulted basins in eastern China [J]. Earth Science, 2004, 29(5): 583-588.
[16] 林畅松, 刘景彦, 张英志, 等. 构造活动盆地的层序地层与构造地层分析—以中国中、新生代构造活动湖盆分析为例[J]. 地学前缘, 2005, 12(4):365-374 doi: 10.3321/j.issn:1005-2321.2005.04.005
LIN Changsong, LIU Jingyan, ZHANG Yingzhi, et al. Sequence stratigraphy and tectono-stratigraphic analysis of tectonically active basins: A case study on the Cenozoic-Mesozoic lacustrine basins in China [J]. Earth Science Frontiers, 2005, 12(4): 365-374. doi: 10.3321/j.issn:1005-2321.2005.04.005
[17] 王英民. 对层序地层学工业化应用中层序分级混乱问题的探讨[J]. 岩性油气藏, 2007, 19(1):9-15 doi: 10.3969/j.issn.1673-8926.2007.01.002
WANG Yingming. Analysis of the mess in sequence hierarchy applied in the industrialized application of the sequence stratigraphy [J]. Lithologic Reservoirs, 2007, 19(1): 9-15. doi: 10.3969/j.issn.1673-8926.2007.01.002
[18] 杨风丽, 何将启, 江兴歌, 等. 东海西湖凹陷第三系油气运聚分析[J]. 海洋石油, 2003, 23(S1):25-29
YANG Fengli, HE Jiangqi, JIANG Xingge, et al. Petroleum migration and accumulation in tertiary for Xihu Sag, East China Sea [J]. Offshore Oil, 2003, 23(S1): 25-29.
[19] 彭伟欣. 东海油气勘探成果回顾及开发前景展望[J]. 海洋石油, 2001, 21(3):1-6 doi: 10.3969/j.issn.1008-2336.2001.03.001
PENG Weixin. Prospects for developments and retrospects for oil/gas exploratory results in the East China Sea [J]. Offshore Oil, 2001, 21(3): 1-6. doi: 10.3969/j.issn.1008-2336.2001.03.001
[20] 刘成鑫. 东海平湖油气田平湖组沉积相研究[J]. 海洋石油, 2010, 30(2):9-13 doi: 10.3969/j.issn.1008-2336.2010.02.009
LIU Chengxin. Study on sedimentary facies for Pinghu Formation in Pinghu oil and gas field in East China Sea Basin [J]. Offshore Oil, 2010, 30(2): 9-13. doi: 10.3969/j.issn.1008-2336.2010.02.009
[21] 胡明毅, 沈娇, 胡蝶. 西湖凹陷平湖构造带平湖组砂岩储层特征及其主控因素[J]. 石油与天然气地质, 2013, 34(2):185-191 doi: 10.11743/ogg20130207
HU Mingyi, SHEN Jiao, HU Die. Reservoir characteristics and its main controlling factors of the Pinghu Formation in Pinghu structural belt, Xihu Depression [J]. Oil and Gas Geology, 2013, 34(2): 185-191. doi: 10.11743/ogg20130207
[22] 吴嘉鹏, 张兰, 万丽芬, 等. 西湖凹陷平湖组物源分析[J]. 中国石油勘探, 2017, 22(2):50-57 doi: 10.3969/j.issn.1672-7703.2017.02.006
WU Jiapeng, ZHANG Lan, WAN Lifen, et al. Provenance analysis of Pinghu Formation in Xihu sag [J]. China Petroleum Exploration, 2017, 22(2): 50-57. doi: 10.3969/j.issn.1672-7703.2017.02.006
[23] 吴嘉鹏. 西湖凹陷平湖组潮汐砂脊的发现及意义[J]. 沉积学报, 2016, 34(5):924-929
WU Jiapeng. Discovery of tidal sand ridges and its significance of Pinghu Formation in Xihu Depression [J]. Acta Sedimentologica Sinica, 2016, 34(5): 924-929.