| 厚层湖泊滩坝砂体成因机制探讨及地质意义—以板桥凹陷沙二段为例 |
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| 引用本文： | 商晓飞,侯加根,程远忠,安振月,姚瑞香,李燕.厚层湖泊滩坝砂体成因机制探讨及地质意义—以板桥凹陷沙二段为例[J].地质学报,2014,88(9):1705-1718. |
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| 作者姓名： | 商晓飞 侯加根 程远忠 安振月 姚瑞香 李燕 |
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| 作者单位： | 中国石油大学（北京）,中国石油大学（北京）,中国石油大港油田公司第四采油厂,中国石油大港油田公司第四采油厂,中国石油大港油田公司第四采油厂,中国石油大学（北京） |
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| 基金项目： | 中石油股份有限公司重点科技攻关项目 |
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| 摘 要： | 滩坝储层是近年来油气勘探、开发的重点目标之一。板桥凹陷沙二段发育典型的厚层湖泊滩坝砂体，单砂体平均厚10余米，垂向上通常累积成厚数十米、内部夹层发育的复合滩坝砂体。根据研究区滩坝砂体的沉积特征、平面形态和发育位置，将滩坝砂体细分为坝中心、坝侧翼、坝间、近岸滩、远岸滩5种微相类型。在古构造、沉积环境等综合研究的基础上，指出该区厚层滩坝砂体是物源、水动力和同生断层在时间和空间上有机结合、共同控制的结果。来自南部的辫状河三角洲砂体作为主力物源为板桥凹陷滩坝沉积提供了物质基础。凹陷缓坡带具有大面积的水动力作用区，控制着滩坝的规模和分布，波浪能量的变化影响着滩坝砂体的相分异。同生断层是板桥凹陷发育厚层滩坝砂体的主导因素。一方面，同生断层控制物源的分配，在断层下降盘具有充足的砂体供应，同时，断面的陡坎部位形成持续的水动力高能环境，并长期接受波浪作用，逐渐形成厚度较大的滩坝砂体；另一方面，同生断层的活动性增加了下降盘基准面上升的概率，为滩坝沉积提供了时间条件，滩坝砂体不再因短期基准面的频繁变化而层层错叠，而是在纵向上连续厚层堆积。断层下降盘是厚层滩坝砂体的有利发育部位，并极易形成构造-岩性圈闭，有利于油气聚集、成藏。
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| 关 键 词： | 滩坝 同生断层 成因机理 沙二段 板桥凹陷 |
| 收稿时间： | 2013/4/27 0:00:00 |
| 修稿时间： | 2013/10/27 0:00:00 |
The Formation Mechanism of the Thick Layer Lacustrine Beach-bar and Its Geological Implications: A Case Study of the Member 2 of Shahejie Formation in Banqiao Sag |
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| shangxiaofei,houjiagen,chengyuanzhong,anzhenyue,yaoruixiang and liyan.The Formation Mechanism of the Thick Layer Lacustrine Beach-bar and Its Geological Implications: A Case Study of the Member 2 of Shahejie Formation in Banqiao Sag[J].Acta Geologica Sinica,2014,88(9):1705-1718. |
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| Authors: | shangxiaofei houjiagen chengyuanzhong anzhenyue yaoruixiang and liyan |
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| Institution: | China University of Petroleum, Beijing,China University of Petroleum, Beijing,No.4 Oil Production Plant, Dagang Oilfield Company Ltd.,No.4 Oil Production Plant, Dagang Oilfield Company Ltd.,No.4 Oil Production Plant, Dagang Oilfield Company Ltd.,China University of Petroleum, Beijing |
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| Abstract: | The beach-bar reservoir is one of the most important targets of oil-gas exploration and development in recent years. Sha-2 member of Banqiao Sag develops typical thick layer lacustrine beach-bar sand bodies. The single sand bodies can be up to 10m thick, and usually form compound beach-bar sand bodies with well developed interbeds and tens of meters thick in vertical profile. The beach-bar sand body is further divided into 5 types of microfacies, namely key bar, side-portion of bar, between-portion of bar, nearshore beach and offshore beach, based on the sedimentary characteristics, plane configuration and developing locations of them in the study area. On the basis of the integrated study of paleotectonics and sedimentary environment, this paper points out that the thick beach-bar sand bodies in this area are formed by the organic combination and collective control of source, hydrodynamics and contemporaneous faults both in time and spatial. The braided river delta sand bodies from the south are the main source and material basis of beach-bar sedimentary in Banqiao Sag. Hydrodynamic action is of large area in the gentle slope, and controls the scale and distribution of beach-bar sand bodies. The change of wave energy influences the microfacies differentiation of beach-bar. The contemporaneous fault is the dominant factor. On one hand, the contemporaneous fault controls the allocation of the material from source, which result in abundant sediments supply in the downthrown wall. The fault fractured surface is of persistently high hydrodynamic energy, and gradually forms thick layer beach-bar sand bodies. On the other hand, the activity of the contemporaneous fault adds the possibility of the base level rising in the downthrown wall and provides enough time for the deposition of beach-bar, thus the sand bodies will no longer stagger stack caused by the frequent change of the base level in a short time but deposit persistently to thick layers vertically. The downthrown wall of the contemporaneous fault is the favorable position for the thick layer beach-bar sand bodies development where structural-lithologic traps are easily formed and conducive to oil-gas accumulation. |
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| Keywords: | beach-bar contemporaneous fault formation mechanism Member 2 of Shahejie Formation Banqiao Sag |
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