| 莺歌海盆地东方-乐东区中新统盖层岩石学特征及封盖性分析 |
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| 引用本文： | 代龙,尤丽,招湛杰,钟佳,徐守立,娄敏.莺歌海盆地东方-乐东区中新统盖层岩石学特征及封盖性分析[J].地球科学,2019,44(8):2677-2685. |
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| 作者姓名： | 代龙 尤丽 招湛杰 钟佳 徐守立 娄敏 |
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| 作者单位： | 1.中海石油(中国)有限公司湛江分公司, 广东湛江 524057 |
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| 基金项目： | 中海石油（中国）有限公司自主立项项目ZYKY-2018-ZJ-01“十三五”国家重大专项2016ZX05024-005 |
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| 摘 要： | 莺歌海盆地东方-乐东区已获得商业气田发现，但针对气田盖层研究，尤其是泥岩盖层岩石学特征及孔喉结构特征方面研究较少.利用岩石薄片、地球化学、XRD、元素分析等资料，深入分析研究区泥岩矿物组成、地球化学、成岩演化以及孔隙结构特征.结果表明:莺歌海盆地东方-乐东区中新统黄一段和黄二段泥岩盖层分布最为稳定，泥岩盖层封盖性受陆源碎屑供给与钙质化石碎片影响较大，研究区优质盖层中陆源碎屑颗粒与钙质化石碎片含量较低，次生溶蚀孔隙与微裂缝不发育；埋藏成岩过程中的粘土矿物转化脱水与有机质热演化排烃是低速泥岩的主要成因；泥岩盖层以微孔喉和超微孔喉为主，此类喉道不利于气体的渗流，对油气向上逸散起明显阻碍，盖层整体封盖性较好.
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| 关 键 词： | 泥岩盖层 岩石学 中新统 东方区 乐东区 莺歌海盆地 |
| 收稿时间： | 2019-01-29 |
Petrological Characteristics and Sealing Analysis of Mesozoic Caprock in Dongfang-Ledong Area,Yinggehai Basin |
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| Abstract: | Commercial gas fields have been discovered in Dongfang-Ledong area of Yinggehai Basin, but little research has been done on gas field caprock, especially on mudstone caprock type and pore throat structure. In this paper, the mineral composition, geochemistry, diagenetic evolution and pore structure characteristics of mudstone in the area are studied in depth by using the data of thin sections, geochemistry, XRD and element analysis.The results show that the distribution of mudstone caprocks in the first and second members of the Mesozoic Huangliu Formation in Dongfang-Ledong area of Yinggehai Basin is the most stable, and the caprocks are greatly influenced by terrigenousclastic supply and calcareous fossil fragments. The content of terrigenousclastic particles and calcareous fossil fragments in the high-quality caprocks in the study area is low, and secondary dissolution pore and micro-fracture are not developed.Dehydration of clay minerals during burial diagenesis and hydrocarbon expulsion by thermal evolution of organic matter are the main genesis of low-velocity mudstones. Mudstone caprock is dominated by microporous throat and ultraporousthroat, which is not conducive to gas seepage and obviously hinders the upward escape of oil and gas, and the overall sealing of caprock is good. |
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