石油与天然气地质 ›› 2025, Vol. 46 ›› Issue (6): 1927-1946.doi: 10.11743/ogg20250612

• 油气地质 • 上一篇    下一篇

苏北盆地低有机碳含量陆相页岩层系页岩油富集高产机理与成藏模式

何希鹏1,2(), 昝灵1,2(), 高玉巧1,2, 蔡潇1,2, 陈鹏1,2, 花彩霞1,2, 白鸾羲1,2, 张琬璐1,2   

  1. 1.页岩油气富集机理与高效开发全国重点实验室,北京 102206
    2.中国石化 华东油气分公司,江苏 南京 210019
  • 收稿日期:2025-08-11 修回日期:2025-11-04 出版日期:2025-12-30 发布日期:2025-12-25
  • 通讯作者: 昝灵 E-mail:hexp.hdsj@sinopec.com;zanl.hdsj@sinopec.com
  • 第一作者简介:何希鹏(1970—),男,研究员,油气地质及勘探评价。E-mail: hexp.hdsj@sinopec.com
  • 基金项目:
    国家自然科学基金联合基金项目(U24B6002);中国石化科技项目(P23190)

Enrichment and high productivity mechanisms and accumulation patterns of shale oil in lacustrine shales with low total organic carbon content in the Subei Basin

Xipeng HE1,2(), Ling ZAN1,2(), Yuqiao GAO1,2, Xiao CAI1,2, Peng CHEN1,2, Caixia HUA1,2, Luanxi BAI1,2, Wanlu ZHANG1,2   

  1. 1.State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development,Beijing 102206,China
    2.East China Oil & Gas Company,SINOPEC,Nanjing,Jiangsu 210019,China
  • Received:2025-08-11 Revised:2025-11-04 Online:2025-12-30 Published:2025-12-25
  • Contact: Ling ZAN E-mail:hexp.hdsj@sinopec.com;zanl.hdsj@sinopec.com

摘要:

苏北盆地古近系阜(阜宁组)二段页岩具有有机质丰度低、岩性复杂和断块破碎的地质特点,页岩油勘探面临资源潜力和富集机理不清、勘探方向不明等难题。系统开展了低总有机碳含量(TOC)页岩成烃、成储和成藏机理,明确了勘探潜力和有利目标。研究结果表明:① 阜二段主要发育5种岩相,其中阜二段一亚段和二亚段的纹层状黏土质-长英质、长英质-碳酸盐混合质页岩为有利岩相。② 页岩有机质类型为Ⅰ-Ⅱ型,发育光面球藻、葡萄藻、沟鞭藻和木栓质体等有利成烃母质,具有“早生烃、高转化、低排烃、富游离”的生-排-滞-聚特征。③ 页岩为裂缝-孔隙型储层,孔隙以黏土矿物晶间孔、长英质矿物粒间孔和溶蚀孔为主,裂缝主要为层理缝、构造缝和成岩缝,裂缝孔隙度占17% ~ 21%。④ 受成岩和构造作用影响,页岩油在源内发生3次微运移,页岩具有微运移-自封闭的成藏特征。⑤ 阜二段具有深凹稳定型、高陡断阶型、复杂断块型和浅埋单斜型4种页岩油成藏模式。⑥ 页岩油富集高产主要受沉积成岩、保存条件和可压性三因素控制。溱潼凹陷实施12口探评井和3个试验井组,均获得高产,提交页岩油探明储量超过4 000 × 104 t,揭示了苏北盆地低TOC页岩油良好的勘探开发潜力。

关键词: 成烃母质, 微运移-自封闭, 富集高产机理, TOC页岩, 成藏模式, 页岩油, 苏北盆地

Abstract:

Shales in the 2nd member of the Funing Formation (also referred to as the Fu 2 Member) in the Subei Basin are characterized by low organic matter abundance, complex lithological composition, and small fault blocks. These geological characteristics pose considerable challenges for shale oil exploration, including uncertainties regarding resource potential, enrichment mechanisms, and exploration targets. To address these issues, we systematically investigate the mechanisms behind the hydrocarbon generation, reservoir formation, and hydrocarbon accumulation in shales with low total organic carbon (TOC) content in the Fu 2 Member. Accordingly, the potential and favorable targets for shale oil exploration of the shales are determined. The results indicate that shales in the Fu 2 Member consist primarily of five lithofacies types, in which lamellar clayey-felsic and felsic-carbonate mixed shales occurring predominantly in the 1st and 2nd sub-members are identified as favorable lithofacies. The shales contain types I and II kerogen, as well as a range of favorable hydrocarbon-generating parent materials, including the Leiosphaeridia, Botryococcus, dinoflagellates, and suberinite, exhibiting early-stage hydrocarbon generation, high conversion rates, low hydrocarbon expulsion efficiency, and significant free oil enrichment. Shale reservoirs in the Fu 2 Member are classified as fractured-porous reservoirs. In these reservoirs, pores are dominated by intercrystalline pores within clay minerals, intergranular pores within felsic minerals, and dissolution pores. Reservoir fractures consist primarily of bedding-parallel fractures, structural fractures, and diagenetic fractures, contributing to 17% ~ 21% of the reservoir porosity. Influenced by diagenesis and tectonic processes, shale oil experienced three stages of micro-migration within the source interval, resulting in the shale oil accumulation characteristics of micro-migration and self-sealing. Four shale oil accumulation patterns are identified in the Fu 2 Member: stable shale oil within deep low-lying zones, as well as shale oil hosted in highly-steep faulted terraces, complex fault blocks, and shallowly-buried monoclines. The enrichment and high productivity of shale oil are primarily governed by sedimentary diagenesis, preservation conditions, and fracability. A total of 12 exploration and appraisal wells, along with three test well groups, were deployed in the Qintong Sag. All wells yielded high productivity, with proven shale oil reserves exceeding 40 million tons having been reported. These results reveal that shales with low TOC content in the Subei Basin hold considerable potential for shale oil exploration and exploitation.

Key words: hydrocarbon-generating parent material, micro-migration and self-sealing, enrichment and high productivity mechanisms, shale with low TOC content, accumulation pattern, shale oil, Subei Basin

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