| 渤海海域秦南凹陷东南缘沙一段混积岩优质储层成因及勘探意义 |
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| 引用本文： | 薛永安,庞小军,郝轶伟,冯冲.渤海海域秦南凹陷东南缘沙一段混积岩优质储层成因及勘探意义[J].地球科学,2020,45(10):3527-3542. |
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| 作者姓名： | 薛永安 庞小军 郝轶伟 冯冲 |
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| 作者单位： | 中海石油(中国)有限公司天津分公司渤海石油研究院, 天津 300459 |
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| 基金项目： | 国家科技重大专项2016ZX05024-003 |
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| 摘 要： | 为了查明秦南凹陷东南缘沙一段混积岩优质储层的成因，利用常规物性、铸体薄片、扫描电镜、碳氧同位素等分析化验资料，对Q29、L25和Q30构造沙一段混积岩储层特征以及优质储层控制因素进行了研究.结果表明:（1）构造背景控制了沙一段混积岩储层的类型、厚度、成分和整体物性，是混积岩优质储层差异的主因.Q29构造沙一段主要发育陡坡带混积扇，由扇三角洲夹生屑滩组成的旋回为主，粒度粗，砾石含量高，陆源碎屑中中酸性火山岩岩屑和砾石含量最高，石英含量低，整体物性较差，但厚度大，以溶蚀孔为主，见大量生物体腔孔.L25构造沙一段主要发育缓坡带混积滩，由扇三角洲与生屑滩的交互、或生屑滩夹扇三角洲为主，粒度细，砾石含量低，陆源碎屑中长石和石英含量高，整体物性较好，厚度中等，溶蚀孔和原生孔发育，见大量生物体腔孔.Q30构造沙一段主要发育水下局部隆起带生屑滩，陆源碎屑含量低，整体物性相对稍差，厚度最薄，溶蚀孔和生物体腔孔为主.（2）受控于不同构造背景下沉积作用的差异，Q29、L25和Q30构造遭受的成岩作用既具有相似性，又具有差异性，咸化湖泊、强波浪淘洗、低泥质含量、早期白云石化、含大量的生物碎屑和泥晶包壳以及酸性溶蚀作用是形成沙一段混积岩优质储层的共同特点.但不同构造遭受的大气淡水淋滤、压实作用、胶结作用、溶解作用强度具有明显的差异性.（3）混积岩储层具有较大的埋深下限，在混积岩优质储层影响因素的约束下，寻找能够形成大中型油气藏的规模较大的陡坡带混积岩储层和物性较好的缓坡带混积岩储层，是目前渤海海域古近系中深层勘探的重要目标之一.
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| 关 键 词： | 混积岩储层 构造背景 沉积环境 成岩作用 沙一段 秦南凹陷 渤海海域 沉积 |
| 收稿时间： | 2020-05-25 |
Genesis of High-Quality Mixed Rock Reservoir and Its Exploration Significance in Es1 around Southeast Margin of Qinnan Sag,Bohai Sea |
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| Abstract: | In order to ascertain the genesis of the high-quality reservoirs of the Es1 in the southeast margin of the Qinnan sag, using conventional physical properties, cast thin sections, scanning electron microscope, carbon and oxygen isotopes and other analytical laboratory data, the characteristics of the Es1 in Q29, L25 and Q30 structures and the control factors of high-quality reservoirs were studied. The results show follows. (1) The tectonic background controls the type, thickness, composition and overall physical properties of the first member of Shahejie mixed rock reservoir, which is the main reason for the difference of high-quality mixed rock reservoir. The Q29 structure mainly develops mixed fans in steep slopes. Longitudinally, it is composed of cycles of fan delta with bioclastic beaches. It has the characteristics of coarse particle size, high gravel content, the highest content of medium-acid volcanic rocks in terrestrial detritus, and low quartz content. Its overall physical properties are poor, the thickness is large, the dissolution pores are dominant, and a large number of biological cavity pores are developed. The L25 structure mainly develops mixed beaches in gentle slopes. Vertically, it is composed of the interaction between fan delta and bioclastic shoal, or bioclastic shoal with fan delta. Development of dissolution pores, primary pores and a large number of biological cavity pores. The Q30 structure mainly develops bioclastic shoals in the local uplift zone under water. It has the characteristics of low content of terrestrial debris, relatively poor overall physical properties, thinnest thickness, dissolution pores and biological cavity pores. (2) Controlled by differences in different tectonic backgrounds and sedimentation, the diagenesis suffered by the Q29, L25, and Q30 structures is both similar and different. Salty lakes, strong wave elutriation, low mud content, early dolomization, containing a large amount of biological debris, the development of mud crystal cladding, and strong acidic dissolution are the common characteristics of the formation of high-quality mixed-rock reservoirs. However, the strength of atmospheric freshwater leaching, compaction, cementation, and dissolution suffered by different structures show obvious differences. (3) The mixed rock reservoir has a large lower limit of burial depth. Constrained by the factors affecting the quality of high-quality mixed rock reservoirs, searching for large-scale and medium-sized oil and gas reservoirs in large-scale steep slope zone mixed rock reservoirs and good physical properties in gentle slope zone mixed rock reservoirs is currently one of the important targets of near-middle-deep exploration in the Paleogene Bohai Sea area. |
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