| 渤海西部沙东南构造带东营组古地貌特征及对沉积的控制作用 |
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| 引用本文： | 康海亮,林畅松,牛成民.渤海西部沙东南构造带东营组古地貌特征及对沉积的控制作用[J].地质力学学报,2021,27(1):19-30. |
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| 作者姓名： | 康海亮 林畅松 牛成民 |
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| 作者单位： | 中国石油勘探开发研究院,北京 100083;中国地质大学(北京)海洋学院,北京 100083;中海石油(中国)有限公司天津分公司,天津 300459 |
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| 基金项目： | 国家科技重大专项（2016ZX05029-005） |
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| 摘 要： | 渤海西部海域沙东南构造带处于沙垒田凸起向沙南凹陷的过渡部位,受继承性凸起、不同时期同沉积断裂和古沟谷多种因素影响,沉积相的发育较为复杂,制约了下步油气勘探。为此,通过分析由地层厚度法恢复的沙东南构造带东营组各三级层序沉积时期的古地貌,明确了研究区发育凸起区、斜坡区、古沟谷、断槽、浅洼和深洼陷区等多种地貌单元。同时,以北北东向转换断裂为界,划分出两种不同的地貌组合分区:西区为由侵蚀沟谷、古潜山斜坡和早期同沉积断裂组成的沟谷-斜坡-断坡地貌,东区为由侵蚀沟谷、2~3条同向不同期同沉积断层组成的沟谷-多级断坡地貌。研究表明两种构造地貌中位于凸起边缘的沟谷早期均为物源通道,晚期接受沉积充填,对沉积相类型、分布以及充填控制的差异主要受斜坡-断坡和多级断坡的影响:在沟谷-斜坡-断坡地貌中,沉积体系的分布和沉积充填过程主要受古斜坡-断坡控制,控制断坡的同沉积断裂在沙河街组活动较强,控制了沙河街组低位扇、浊积扇的沉积和充填,SQ-Ed3时期断裂活动逐渐减弱,继承性断坡地貌成为SQ-Ed3层序扇三角洲平原和前缘以及SQEd2d,SQ-Edu2时期辫状河三角洲前缘和滨浅湖沉积的大致界限;在沟谷-多级断坡地貌中,形成于SQ-Ed3时期的沙东南1号断裂仅在SQ-Ed3时期活动,控制了深洼陷的形成和一级坡折之下小型扇三角洲的发育,形成于SQ-Ed2d时期的沙南断裂主要活动时期也在SQ-Ed2d,形成了分隔凸起与斜坡间的二级坡折,控制了SQ-Ed2d小型扇三角洲的沉积充填。
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| 关 键 词： | 沉积充填 断裂组合 古地貌 东营组 沙东南构造带 渤海西部 |
| 收稿时间： | 2019/11/29 0:00:00 |
| 修稿时间： | 2020/8/11 0:00:00 |
Ancient landform of the Dongying formation in the Shadongnan structural zone, western Bohai Sea area and its control on the sedimentation |
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| KANG Hailiang,LIN Changsong,NIU Chengmin.Ancient landform of the Dongying formation in the Shadongnan structural zone, western Bohai Sea area and its control on the sedimentation[J].Journal of Geomechanics,2021,27(1):19-30. |
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| Authors: | KANG Hailiang LIN Changsong NIU Chengmin |
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| Institution: | 1.Petrochina Research Institute of Petroleum Exploration and Development, Beijing 100083, China2.School of Ocean Sciences, China University of Geosciences(Beijing), Beijing 100083, China3.Tianjin Branch, CNOOC China Limited, Tianjin 300459, China |
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| Abstract: | The Shadongnan structural zone in the western Bohai Sea area is located in the transitional position from the Shaleitian uplift to the Sha''nan sag. Due to the influence of various factors such as inherited uplift, syn-depositional faults and ancient valleys in different periods, the development of sedimentary facies is relatively complex, restricting the further oil and gas exploration and development. We restored the ancient landform of each three-level sequence in the Dongying formation in the sedimentary period using the strata thickness method, identifying uplifts, slopes, ancient valleys, fault troughs, and shallow and deep sub-sags in the study area. Meanwhile, there are two kinds of ancient landform in the Shadongnan structural zone bounded by the NNE-trending transform fault, with the valley-paleoslope-fault slope-break in the west and the valley-multistage fault slope-break in the east. The former is composed of eroded valleys, buried hill slopes and early syn-depositional faults, while the latter eroded valleys and two or three syn-depositional faults with the same direction and different periods. Our study showed that the valleys located at the edge of the uplifts were the source channels in the early stage and filled with sediments in the late stage. The distribution and filling of the sedimentary system of the valley-paleoslope-fault slope-break were mainly controlled by the ancient slope-fault slopes, and the syn-depositional faults controlling the fault slopes were relatively active in the Shahejie formation and controlled the deposition and filling of the lowstand fans and turbidite fans. By the SQ-Ed3 period, the fault activities gradually weakened, and the fault slope-break distinct the fan delta plain and front in SQ-Ed3 from the deposition of the braided river delta front and shallow lake in SQ-Ed2d and SQ-Ed2u. The Shadongnan No.1 syn-depositional fault with the valley-multistage fault slope-break, which was developed and activated in SQ-Ed3, controlled the formation of the deep sub-sags and the development of the small fan deltas under the first slope break. The Sha''nan syn-depositional fault both formed and activated in SQ-Ed2d was acted as the second slope break separating the bulges and slopes, and controlled the depositional filling of the small fan delta in SQ-Ed2d. |
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| Keywords: | depositional filling fault combination ancient landform Dongying formation Shadongnan structural zone western Bohai Sea area |
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