| 琼东南盆地井震地层对比分析及区域地层格架的建立 |
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| 引用本文： | 陈宏言,孙志鹏,翟世奎,刘新宇,刘晓锋,罗威,修淳.琼东南盆地井震地层对比分析及区域地层格架的建立[J].海洋学报,2015,37(5):1-14. |
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| 作者姓名： | 陈宏言 孙志鹏 翟世奎 刘新宇 刘晓锋 罗威 修淳 |
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| 作者单位： | 1.中国海洋大学 海底科学与探测技术教育部重点实验室, 山东 青岛 266100 |
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| 基金项目： | 国家科技重大专项课题(2011ZX05025-002-03)。 |
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| 摘 要： | 琼东南盆地历经断陷、断坳、裂后热沉降和裂后加速沉降等一系列的构造变动,沉积环境由始新世的滨海环境发展为现今的深水环境,形成了一套包括滨岸沉积、滨浅海沉积、陆架和陆坡沉积、以及半深海沉积的地层组合,具有良好的油气资源的生储盖条件,已成为当前油气资源勘探开发的重点区域。本文首先对盆地区域内钻井和地震剖面进行了主要地层界面(T20、T30、T40、T50、T60和T70)的识别和提取(点),继而结合连井地震剖面(线)和盆地区域过井地震剖面(面)对主要地层界面做了追踪对比分析,再依据古生物年代,建立了适用于琼东南盆地的区域地层年代格架。在琼东南盆地浅水区主要沉积了新近系地层(T60-T20),断裂基本不发育,地层厚度变化不大,极少有明显的上超和削截,局部地区发育有利于油气储集的三角洲沉积体系,表明琼东南盆地新近纪时期受构造作用影响较小。在深水区,新近系地层(T60-T20)和浅水区特征相似,仅反射特征有所不同;古近系地层(T100-T60)内部层序结构主要为楔状或近平行状,具有明显的上超和削截,地层厚度较大,断裂明显并导致地层错断,表明琼东南盆地深水区在古近纪时期主要受构造作用控制,并伴随着强烈的拉张和快速沉降作用,沉积环境主要为浅海。在近东西向的中央峡谷内存在有三期砂体:第一期砂体(井深3 528~3 336m,厚约192m)形成于距今11.6~5.5Ma(T40-T30),分布范围跨越中央峡谷的陵水-松南-宝岛段,沉积物构成包括浊积水道沉积、浊积席状砂、块体流沉积、深海泥质沉积、天然堤及漫溢沉积等;第二期砂体(井深4 100~3 900m,厚约200m)形成于距今5.5~4.2Ma(T30-T29),分布范围跨越中央峡谷的乐东-陵水段,以重力流沉积为主;第三期砂体(深度3 630~3 400m,厚约230m)发育于距今4.2~3.6Ma(T29-T28),分布于峡谷的乐东-莺东段,以浊积水道沉积为主。三期砂体在琼东南盆地中央坳陷带自东向西、由老到新依次展布,构成了良好的油气储层体。
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| 关 键 词： | 琼东南盆地 井震地层对比分析 古生物年代 区域地层格架 中央峡谷砂体 |
| 收稿时间： | 2014/12/28 0:00:00 |
| 修稿时间： | 2/6/2015 12:00:00 AM |
Analysis of well-seismic stratigraphic correlation and establishment of regional stratigraphic framework in the Qiongdongnan Basin of northern South China Sea |
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| Chen Hongyan,Sun Zhipeng,Zhai Shikui,Liu Xinyu,Liu Xiaofeng,Luo Wei and Xiu Chun.Analysis of well-seismic stratigraphic correlation and establishment of regional stratigraphic framework in the Qiongdongnan Basin of northern South China Sea[J].Acta Oceanologica Sinica (in Chinese),2015,37(5):1-14. |
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| Authors: | Chen Hongyan Sun Zhipeng Zhai Shikui Liu Xinyu Liu Xiaofeng Luo Wei and Xiu Chun |
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| Institution: | 1.The Key Lab of Submarine Geosciences and Prospecting Techniques, Ministry of Education, Ocean University of China, Qingdao 266100, China2.Zhanjiang Branch Institute of China National Offshore Oil Corporation (CNOOC) Limited, Zhanjiang 524057, China |
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| Abstract: | The Qiongdongnan Basin experienced a series of tectonic activities from faulting,through fault-depression and post-faulting thermal subsidence to post-faulting accelerated subsidence,had a sedimentary environment from coast in Eocene to deep-sea in present,formed a set of strata combination including littoral sediments,offshore sediments,shelf-slope sediments and bathyal sediments,and possessed favorable source-reservoir-cap conditions for hydrocarbon accumulation. Thus it is considered as an important region of hydrocarbon exploration and development. In this study,the key strata interfaces (T20,T30,T40,T50,T60 and T70) in the wells-through seismic profiles were identified,then were tracked and correlated combined with the regional wells-tie seismic profiles in the basin. On this basis,the regional stratigraphic framework of the Qiongdongnan Basin was established associated with the age of fossil assemblages. The Neogene strata (T60-T20) are primary in the shallow water area,in which the faults are rarely distributed,the stratigraphic thickness has little variation,and onlaps and truncations can be rarely found. Delta sedimentary system,which is beneficial to hydrocarbon reservoir,develops highly in local area. The evidence mentioned above indicates that tectonism exerted trivial influence on the Qiongdongnan Basin during the Neogene. The characteristics of the Neogene strata (T60-T20) in the deep water area are similar to that in the shallow water except seismic reflection characteristics. The internal sequence structure of the Paleogene strata (T100-T60) is dominantly sphenoid or subparallel with obvious onlaps and truncations. The thickness of the strata is large,and obvious faults result in strata fractures. These characteristics imply that the deep water area in the Qiongdongnan Basin was controlled mainly by tectonism,accompanying with the strong extension and rapid subsidence,and being in neritic environment during the Paleogene. Three stages of sand bodies are identified in the Central Canyon from east to west: the first stage (depth of 3 528-3 336 m,thickness of about 192 m) formed during 11.6-5.5Ma B.P. (T40-T30) distributes in the Lingshui-Songnan-Baodao segment of the Central Canyon,which includes turbidite channel deposit,turbidite sheet sand,mass flow deposit,deep-sea politic deposit,natural levee and overflow deposit; the second stage (depth of 4 100-3 900 m,thickness of about 200 m) formed during 5.5~4.2Ma B.P. (T30-T29),spans Ledong-Lingshui segment of the Central Canyon,being primarily composed of gravity flow deposits; the third stage(depth of 3 630-3 400 m,thickness of about 230 m) formed during 4.2-3.6Ma B.P. (T29-T28),presents in the Ledong-Yingdong segment of the Central Canyon,consisting mainly of turbidite channel deposits. The three stages of sand bodies from oldest in the east to youngest in the west,constituted the favorable reservoirs in the Central Depression Belt of the Qiongdongnan Basin. |
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| Keywords: | the Qiongdongnan Basin well-seismic stratigraphic correlation analysis age of fossil assemblages regional stratigraphic framework sand bodies of the Central Canyon |
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