| 珠江口盆地恩平凹陷新近系储层菱铁矿胶结物成因及对物性的影响 |
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| 引用本文： | 杨娇,戴建文,吴雪晴,涂乙,董硕,李琦.珠江口盆地恩平凹陷新近系储层菱铁矿胶结物成因及对物性的影响[J].地质科技通报,2023,42(2):127-136. |
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| 作者姓名： | 杨娇 戴建文 吴雪晴 涂乙 董硕 李琦 |
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| 作者单位： | 中海石油(中国)有限公司深圳分公司, 广东 深圳 518000 |
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| 基金项目： | 中海石油（中国）有限公司深圳分公司项目CCL2022SZPS0130 |
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| 摘 要： | 为了厘清菱铁矿胶结物的成因，研究菱铁矿胶结物对储层的影响及其储层地质模式，探讨含菱铁矿的储层对于油田开发生产的影响，开展菱铁矿胶结物成因及对物性的影响研究。基于常规岩心、薄片鉴定、X衍射等资料，对珠江口盆地恩平油区中浅储层胶结物类型及特征统计发现，该区菱铁矿胶结物富集。通过古海洋氧化还原状态和沉积环境研究了其成因机制，并定量研究了菱铁矿对储集层质量的影响。结果表明:研究区储层中菱铁矿是成岩作用过程中由有机质降解产生的CO2与孔隙水中富集的Fe2+结合的产物，形成于砂岩原生孔隙发育的早成岩期，对储层整体孔隙的保存具有积极意义；但菱铁矿胶结的局部（多发育于薄层泥质条带中），由于其占据了较大比例的原生孔隙空间，对储层具有较大破坏性。菱铁矿胶结物的"控渗"作用使泥质条带处纵向渗透率远远低于其他方向渗透率，从而大大增加了泥质薄层对底水的遮挡效果。研究成果在B油田进行应用时发现，富菱铁矿胶结物含水平条带状夹层导致高部位出现能量供给不足，通过"自源闭式助流注热水"用以增能，促使油田产量翻番，大幅提高油藏采出程度。
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| 关 键 词： | 珠江口盆地 恩平油区 中浅层油藏 菱铁矿 胶结物 渗透率 泥质薄层 |
| 收稿时间： | 2021-04-28 |
Quantitative evaluation of the influence of siderite cements on middle-shallow reservoirs: A case study of the southern oil area in the Enping Sag,Pearl River Mouth Basin |
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| Affiliation: | Shenzhen Branch, CNOOC China Limited, Shenzhen Guangdong 518000, China |
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| Abstract: | In order to clarify the cause of formation of siderite cement, and study the influence of siderite cement on reservoir and its geological model, and explore the influence of siderite-bearing reservoir on oilfield development and production, the study of the cause of formation of siderite cement and its influence on physical properties was carried out. Based on conventional core analysis, thin section analysis and X-ray analysis, statistics on the types and characteristics of cements in middle-shallow reservoirs in the Enping oil area, Pearl River Mouth Basin, reveal that siderite cement is abundant. The redox state and sedimentary environment of the paleo-ocean were used to study the genetic mechanism of siderite and quantitatively study the influence of siderite on middle-shallow reservoir quality. The results show that siderite in the reservoir is the product of the combination of CO2 produced by the degradation of organic matter and Fe2+ enriched in pore water during diagenesis. It formed in the early diagenetic stage when the primary pores of sandstone developed, which has a positive significance for the preservation of the overall pores of the reservoir. However, the local cementation of siderite (mostly developed in thin argillaceous belts) is destructive to the reservoir because it occupies a large proportion of the primary pore space. The "permeability control" effect of siderite cement makes the vertical permeability of the muddy strip much lower than that in other directions, thus greatly increasing the shielding effect of the muddy thin layer on the bottom water, which is conducive to reservoir development. Due to the blocking of argillaceous belts, the reservoir geological pattern will change from bottom water reservoir to edge water reservoir and edge water reservoir to multilayer edge water reservoir, which can be exploited by corresponding development measures. The development of siderite leads to differences in the energy supply in the top, middle and edge of the reservoir, which can guide water injection and improve the well pattern strategy. The research results were applied in Oilfield B, where the horizontal strip interlayer of fulling siderite cements resulted in insufficient energy supply in the high position. By injecting hot water to increase energy, oil field production is doubled, and reservoir recovery is greatly improved. |
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