新疆石油地质

新疆石油地质 ›› 2025, Vol. 46 ›› Issue (6): 659-667.doi: 10.7657/XJPG20250602

• 油气勘探 • 上一篇    下一篇

吉木萨尔凹陷芦草沟组页岩油甜点储集层孔隙成因及成岩演化

毛新军a(), 王然b(), 郑孟林b, 李菁b, 潘进b, 王韬b, 黄立良b, 常秋生b   

  1. a.中国石油 新疆油田分公司 新疆 克拉玛依 834000
    b.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:2025-04-30 修回日期:2025-07-17 出版日期:2025-12-01 发布日期:2025-12-05
  • 通讯作者: 王然 E-mail:mxj7341n@petrochina.com.cn;nuture@petrochina.com.cn
  • 作者简介:毛新军（1973-），男，浙江温岭人，教授级高级工程师，硕士，油气勘探，（Email）mxj7341n@petrochina.com.cn
  • 基金资助:
    中国石油前瞻性基础性技术攻关项目(2022DJ0108);中国石油科技项目(2023ZZ24)

Pore Genesis and Diagenetic Evolution of Shale Oil Sweet Spot Reservoirs in Lucaogou Formation, Jimsar Sag

MAO Xinjuna(), WANG Ranb(), ZHENG Menglinb, LI Jingb, PAN Jinb, WANG Taob, HUANG Liliangb, CHANG Qiushengb   

  1. a. PetroChina, Xinjiang Oilfield Company, Xinjiang 834000, China
    b. PetroChina, Xinjiang Oilfield Company, Research Institute of Exploration and Development, Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China
  • Received:2025-04-30 Revised:2025-07-17 Online:2025-12-01 Published:2025-12-05
  • Contact: WANG Ran E-mail:mxj7341n@petrochina.com.cn;nuture@petrochina.com.cn

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摘要： 准噶尔盆地吉木萨尔凹陷二叠系芦草沟组页岩油甜点储集层岩性复杂、物性变化快，成岩作用对页岩油甜点储集层孔隙演化具有重要影响。利用岩石薄片、铸体薄片、扫描电镜、X射线衍射等研究储集层孔隙微观特征，旨在揭示孔隙成因、物性变化规律及控制因素。结果表明：吉木萨尔凹陷芦草沟组甜点主要发育砂岩类和白云岩类储集层，2类储集层孔隙类型均以粒间溶孔、粒内溶孔、铸模孔、溶蚀缝等次生孔隙为主，孔隙直径大于50 μm的宏孔占50%以上；砂岩类和白云岩类储集层物性相当，属于中—低孔低—特低渗储集层，砂岩类储集层平均孔隙度为13.51%，平均渗透率为0.81 mD，白云岩类储集层平均孔隙度为12.86%，平均渗透率为2.38 mD；2类储集层均经历压实作用—风化淋滤溶蚀作用—胶结作用—有机酸溶蚀作用，整体处于中成岩阶段A期；表生成岩阶段的风化淋滤溶蚀作用促进了毛细管孔隙、超毛细管孔隙等大孔隙的形成，该孔隙为主要储集空间，中成岩阶段的有机酸溶蚀作用促进了纳米级微毛细管孔隙的形成，对储集层物性改善有限。

关键词: 吉木萨尔凹陷, 芦草沟组, 页岩油, 孔隙成因, 孔隙类型, 孔隙结构, 成岩作用, 成岩演化

Abstract:

The shale oil sweet spot reservoirs of the Permian Lucaogou formation in the Jimsar sag of Junggar Basin are characterized by complex lithology and greatly varying physical properties, and diagenesis has played an important role in the pore evolution of these reservoirs. Using rock slice, cast thin section, scanning electron microscopy (SEM) and X-ray diffraction (XRD), this paper studies the microscopic characteristics of the pores in the reservoirs to reveal pore genesis, and variations and controlling factors of reservoir physical properties. The results indicate two types of reservoirs, i.e. sandstone reservoir and dolomite reservoir are developed in the sweet spots of Lucaogou formation in the Jimsar sag. Both reservoirs are dominated by secondary pores such as intergranular dissolution pores, intragranular dissolution pores, moldic pores and dissolution fractures, and contain the macropores with diameter >50 μm accounting for more than 50%. The sandstone reservoir and dolomite reservoir have similar physical properties, belonging to medium porosity and low-ultra-low permeability reservoirs. The average porosity and permeability of the sandstone reservoir are 13.51% and 0.81mD, respectively. The dolomite reservoir exhibits an average porosity of 12.86% and an average permeability of 2.38 mD. Both reservoirs have undergone compaction, weathering/leaching dissolution, cementation, and organic acid dissolution, and are in phase A of the middle diagenetic stage. The weathering/leaching dissolution in the epidiagenetic stage accelerated the formation of large pores like capillary pores and supercapillary pores, which are the main contributors to reservoir space. The dissolution of organic acid in the middle diagenetic stage promoted the formation of nanoscale microcapillary pores, which exerted a limited improvement on reservoir physical properties.

Key words: Jimsar sag, Lucaogou formation, shale oil, pore genesis, pore type, pore structure, diagenesis, diagenetic evolution

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