石油与天然气地质 ›› 2025, Vol. 46 ›› Issue (4): 1250-1266.doi: 10.11743/ogg20250415

• 油气地质 • 上一篇    下一篇

准噶尔盆地玛湖凹陷全油气系统成储机制差异性

康逊1(), 谭静强1, 胡文瑄2, 靳军3, 胡瑞璞1,2, 曹剑2   

  1. 1.中南大学 地球科学与信息物理学院,湖南 长沙 410083
    2.南京大学 地球科学与工程学院,江苏 南京 210023
    3.中国石油 新疆油田分公司 勘探开发研究院,新疆 克拉玛依 834000
  • 收稿日期:2025-05-20 修回日期:2025-07-11 出版日期:2025-08-30 发布日期:2025-09-06
  • 第一作者简介:康逊(1989—),男,副教授、博士研究生导师,石油地质学和沉积岩石学。E-mail: xunkang@csu.edu.cn
  • 基金项目:
    国家自然科学基金面上项目(42272179)

Differences in reservoir formation mechanisms across the whole petroleum system in the Mahu Sag, Junggar Basin

Xun KANG1(), Jingqiang TAN1, Wenxuan HU2, Jun JIN3, Ruipu HU1,2, Jian CAO2   

  1. 1.School of Geosciences and Info-physics,Central South University,Changsha,Hunan 410083,China
    2.School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China
    3.Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China
  • Received:2025-05-20 Revised:2025-07-11 Online:2025-08-30 Published:2025-09-06

摘要:

准噶尔盆地玛湖凹陷全油气系统成储机制存在差异性。以该系统代表性储油层下二叠统风城组、上二叠统乌尔禾组及下三叠统百口泉组—上三叠统白碱滩组为研究对象,研究岩石学、储集空间与物性特征,结合元素、碳氧同位素分析研究主要层位的烃-水-岩作用机理,分析了成储机制的差异性。研究结果表明:① 沉积过程、烃-水-岩作用与伴生的矿物溶蚀是上乌尔禾组至三叠系粗碎屑优质储层形成的主控因素。不同储油层位烃-水-岩作用机理与矿物溶蚀特征存在明显差异。上乌尔禾组以早成岩期火山物质蚀变形成的浊沸石普遍胶结为特征,在含烃流体所携带有机酸作用下浊沸石再次溶蚀,其溶蚀孔成为该组主要储集空间。② 百口泉组发生了高价Mn和Fe氧化物诱发的烃类热氧化作用,生成了大量亏损13C同位素的CO2,钾长石溶蚀改善了储层物性,特别是渗透率。中三叠统克拉玛依组由于氧化性物质供给有限,仅有限烃类被氧化。含烃流体携带的有机酸导致钾长石部分溶蚀,局部改善了储层质量。白碱滩组几乎没有受到烃-水-岩作用影响,储层质量主要受沉积和钙质胶结程度影响。③ 风城组页岩油储层受岩相控制显著,压实和胶结作用使储层物性变差,生烃产生的有机酸导致碳酸盐矿物和长石溶蚀,改善了储层物性。④ 深层粗碎屑岩优质储层发育通常与烃-水-岩作用密切相关,需重视该过程的机理性研究。富有机质细粒储层研究应关注不同岩相产生的差异性。

关键词: 烃类氧化, 烃-水-岩相互作用, 全油气系统, 储层成因, 玛湖凹陷, 准噶尔盆地

Abstract:

The Mahu Sag in the Junggar Basin exhibits differential reservoir formation mechanisms across its whole petroleum system (WPS). In this study, we investigate the petrology, reservoir spaces, and physical properties of representative oil-bearing strata in the WPS, including the Lower Permian Fengcheng Formation, the Upper Permian Urho Formation, and the Lower Triassic Baikouquan Formation to the Upper Triassic BaiJiantan Formation. By combining analyses of major elements and carbon-oxygen isotopes, we examine the mechanisms governing hydrocarbon-water-rock interactions in these formations and analyze the differences in the reservoir formation mechanisms. The results indicate that primary factors controlling the formation of high-quality coarse-grained clastic reservoirs from the Upper Permian Urho Formation to the Triassic strata include sedimentary processes, hydrocarbon-water-rock interactions, and associated mineral dissolution. Different oil-bearing horizons show significantly varying hydrocarbon-water-rock interaction mechanisms and mineral dissolution characteristics. Specifically, the Upper Permian Urho Formation is characterized by extensive laumontite cementation formed by the volcanic material alteration during early diagenesis. Laumontite re-dissolution occurred under the action of organic acids carried by hydrocarbon-bearing fluids, and the resulting dissolution pores act as the primary reservoir spaces in the Upper Permian Urho Formation. In the Baikouquan Formation, high-valent Mn and Fe oxides induced the thermal oxidation of hydrocarbons, generating significant amounts of 13C-deficient CO2. The resulting dissolution of K-feldspar enhanced reservoir physical properties, especially permeability. In the Middle Triassic Karamay Formation, only limited hydrocarbons were oxidized due to an insufficient supply of oxidizing agents. Instead, organic acids carried by hydrocarbon-bearing fluids induced the partial dissolution of K-feldspar, enhancing reservoir quality locally. In contrast, the Baijiantan Formation experienced minimal hydrocarbon-water-rock interactions, with reservoir quality predominantly dictated by sedimentation and the degree of calcareous cementation. Shale oil reservoirs in the Fengcheng Formation are significantly governed by lithofacies. In this formation, compaction and cementation reduced reservoir physical properties. In contrast, organic acids produced during hydrocarbon generation promoted the dissolution of carbonate minerals and feldspar, improving reservoir physical properties. Generally, the development of high-quality deep coarse-grained clastic reservoirs in the Mahu Sag is intimately associated with hydrocarbon-water-rock interactions. Therefore, the mechanisms behind these interactions merit greater attention. Additionally, research on organic-rich, fine-grained reservoirs should highlight the differences caused by varying lithofacies.

Key words: hydrocarbon oxidation, hydrocarbon-water-rock interaction, whole petroleum system, reservoir genesis, Mahu Sag, Junggar Basin

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