摘要
当前层序地层格架的建立依据大多源自于河口附近地层叠置规律的分析,而忽略了地层叠置关系在沉积体侧向上的变化,以至于体系域的划分标准受到沉积体范围的限制,使得层序地层划分方案不具有唯一性,难以开展凹陷内更大范围的地层对比。以珠江口盆地中中新世13.8 Ma的陆坡为例,利用井-震综合分析的方法,详细阐述层序边界(SB)特征、下降体系域(FSST)及低位体系域(LST)的地层叠置样式在侧向上的变化。认为与LST进积体系地震上可侧向追踪对比的一系列上超地层应命名为LST,而不是TST。基于区域等时对比的原则,将LST定义修订为形成于基准面上升早期,以可容空间增加速率小于沉积物供给速率为相标志,同时包含侧向上与之等时对比的一套地层;将HST定义修订为形成于基准面上升晚期,以可容空间增加速率小于沉积物供给速率为相标志,同时包含侧向上与之等时对比的一套地层;将TST定义为可容空间增加速率大于沉积物供给速率,同时排除侧向上与LST和HST等时对比的两套地层。建议被动陆缘层序地层格架的建立方法应以河口、陆架和深水作为一个有机整体,寻找各体系域的"唯一性"相标志,开展三维空间上的系统对比和检验,而非人为的对一个沉积体系分块建立层序地层格架。
Current construction of sequence stratigraphic framework is mainly based on the analysis of stratigraphic superposition patterns near the estuary,with their lateral variation in the sedimentary body neglected.So the division standards of system tracts are restricted by the range of sedimentary bodies,and the sequence stratigraphic division scheme is not unique.As a result,it’s difficult to carry out stratigraphic correlation in a larger scope in a sag.The study took a case of Pearl River Mouth Basin clinoform in 13.8 Ma(belongs to the Middle Miocene),and elaborated the characteristics of sequence boundary(SB),and the lateral variations of stratigraphic superposition patterns in Falling Stage System Tract(FSST)and Low stand System Tract(LST),through combination analysis of well and seismic data.The results show that a series of onlapping strata,which can be laterally tracked and correlated with LST progradation systems on seismic sections,should be named as LST rather than TST.Based on the principle of regional isochronous correlation,the definition of LST should be revised as a set of strata that are developed in the early of base-level rising cycle,marked by accommodation increasing rate being lower than the sediment supply rate,and contain lateral equivalent beds.While the definition of HST is revised as a set of strata that are formed in the late of base-level rising cycle,marked by the accommodation increasing rate being less than the sediment supply rate,and include a set of lateral equivalent beds.Meanwhile,the TST is defined as a set of strata with facies marker of the accommodation increasing rate being greater than the sediment supply rate and the lateral equivalents of LST and HST being excluded.Thus we proposed that the reconstruction of sequence stratigraphy framework should take estuary,shelf and deep water as an integrated whole,looking for the unique facies marker of each system tract,and carrying out systematic comparison and checking in three-dimensional space,rather than factitiously splitting
作者
徐少华
何敏
庞雄
陈维涛
王英民
卓海腾
秦春雨
Xu Shaohua;He Min;Pang Xiong;Chen Weitao;Wang Yingmin;Zhuo Haiteng;Qin Chunyu(Chongqing Key Laboratory of Complicated Oil and Gas Field Exploration and Development,Chongqing University of Science and Technology,Chongqing 401331,China;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Shenzhen Branch of COONC Ltd.,Guangdong,Guangzhou 510240,China;Ocean College,Zhejiang University,Hangzhou,Zhejiang 310058,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2018年第4期811-822,共12页
Oil & Gas Geology
基金
油气资源与探测国家重点实验室开放课题基金项目(PRP/open-1805)
重庆市教育委员会科学技术研究项目(KJ1713333)
关键词
侧向变化
体系域
地震地层学
层序地层学
珠江口盆地
lateral variation
system tract
seismic stratigraphy
sequence stratigraphy
Pearl River Mouth Basin
