新疆石油地质

›› 2017, Vol. 38 ›› Issue (1): 1-1.doi: 10.7657/XJPG20170102

• 论文 •    

克拉苏冲断带克深区带白垩系超深储集层成岩演化

李玲1，唐洪明1，王茜2a，唐胜蓝2a，冯伟2b，王珠峰1   

  1. (1.西南石油大学 a.油气藏地质及开发工程国家重点实验室;b.地球科学与技术学院,成都 610500;2.中国石油 塔里木油田分公司 a.油气工程研究院;b.开发事业部,新疆 库尔勒 841000)
  • 出版日期:2019-01-01 发布日期:1905-07-13

Diagenetic Evolution of Cretaceous Ultra-Deep Reservoir in Keshen Belt, Kelasu Thrust Belt, Kuqa Depression

LI Ling1, TANG Hongming1, WANG Xi2a, TANG Shenglan2a, FENG Wei2b, WANG Zhufeng1   

  1. (1.Southwest Petroleum University a.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation; b.School of Geoscience and Technology, Chengdu, Sichuan 610500, China; 2.PetroChina Tarim Oilfied Company a.Oil and Gas Engineering Research Institute; b.Department of development, Korla, Xinjiang 841000, China)
  • Online:2019-01-01 Published:1905-07-13

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摘要： 为探讨克拉苏冲断带克深区带白垩系巴什基奇克组超深储集层成岩机制与环境演化，应用岩石薄片、阴极发光、扫描电镜、流体包裹体测温及激光拉曼成分、能谱及主微量元素等分析手段，结合成岩标志矿物，刻画了超深层致密砂岩成岩演化特征。研究区白垩系超深储集层主要经历了碱性-弱酸性-碱性-酸性的流体演化过程，成岩流体与成岩矿物共生关系组合为：早期碱性流体阶段的铁染泥质包膜和泥晶碳酸盐矿物组合；表生酸性流体环境下的长石溶蚀和石英次生加大组合；回归碱性环境的石英溶蚀、硬石膏、白云石和长石次生加大组合；晚期酸性环境下的钾长石溶蚀、自生石英和丝发状伊利石组合。碱性胶结物占据大量孔隙及早期裂缝，降低了储集层的渗透能力，减孔量为10%~12%；晚期天然气充注携带的酸性流体沿粒缘缝、构造缝等优势运移通道对酸溶矿物进行溶蚀，形成大量溶蚀扩大孔及缝，改善了超深储集层物性，增孔量为2%~3%. 因此，超深储集层有效储集空间受控于先碱性后酸性的成岩环境，碱性成岩产物为晚期酸性溶蚀提供物质基础，晚期酸性成岩环境对超深储集层物性的后期改善具有关键作用，酸性流体来自表生成岩阶段大气水淋滤和晚期天然气充注。

Abstract: In order to thoroughly investigate the diagenetic mechanism and environmental evolution of ultra-deep reservoir of the Cretaceous Bashijiqike formation in Keshen belt, by using the thin section observation, cathode luminescence analysis,scanning electron microscope, fluid inclusion microthermometry and laser raman spectum, energy spectrum analysis, the major and trace element analysis and other technical means, combined with diagenetic mineral, this paper portrays the characterization of diagenetic evolution of ultra-deep tight sandstone. The results show that ultra-deep reservoir had experienced alkaline-weak acidic-alkaline-acidic diagenetic environment. The combination of diagenetic fluid and diagenetic mineral: clay coating stained by iron and crystal carbonate in the early stage of alkaline fluid environment; dissolution of plagioclase and quartz overgrowth under the environment of epi-diagenetic; return to the alkaline environment with quartz dissolution, anhydrite cementation, dolomite cementation and feldspar overgrowth; in the late acidic environment with the dissolution of potassium feldspar, micro-crystalline quartz and illite. Alkaline cement products have occupied a large number of pores and the cracks formed in the early stage, which seriously damaged the permeability of the reservoir, the porosity was reduced by 10%~12%. While the acidic fluids carried by lately hydrocarbon charging can dissolute the acid-solube minerals and form dissolved pore and fracture network with the porosity increasing by 2%~3%. Therefore, the effective reservoir space of the ultra-deep reservoir is controlled by early alkaline and late acidic diagenesis environment. The alkaline diagenetic products provide the material basis for the lately acid corrosion, and the late acidic diagenetic environment plays an important role in the late improvement of the physical properties of the ultra-deep reservoir. The acid fluid is mainly controlled by atmospheric water infiltration in epi-diagenetic stage and lately hydrocarbon charging

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