Acta Scientiarum Naturalium Universitatis Pekinensis ›› 2018, Vol. 54 ›› Issue (2): 373-384.DOI: 10.13209/j.0479-8023.2017.135

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Diagenesis Types and Evolution of the Lower-Middle Ordovician Carbonates in Yubei Area, Tarim Basin

LIU Hongguang1,2, LIU Bo2,†, ZHANG Xuefeng2, CAO Jianhua3, HUANG Chenjun1,2, LIU Geyun4, WU Shuanglin1,2   

  1. 1. School of Earth and Space Sciences, Peking University, Beijing 100871
    2. Institute of Oil and Gas, Peking University, Beijing 100871
    3. College of Computer Science and Information Technology, Tianjin University of Science and Technology, Tianjin 300222
    4. School of the Earth Science and Resources, China University of Geosciences (Beijing), Beijing 100083
  • Received:2017-01-04 Revised:2017-06-20 Online:2018-03-20 Published:2018-03-20
  • Contact: LIU Bo, E-mail: bobliu(at)pku.edu.cn

塔里木盆地玉北地区中—下奥陶统碳酸盐岩成岩作用类型及演化

刘红光1,2, 刘波2,†, 张学丰2, 曹鉴华3, 黄臣军1,2, 刘格云4, 吴双林1,2   

  1. 1. 北京大学地球与空间科学学院, 北京 100871
    2. 北京大学石油与天然气研究中心, 北京 100871
    3. 天津科技大学计算机科学与信息工程学院, 天津 300222
    4. 中国地质大学(北京)地球科学与资源学院, 北京 100083
  • 通讯作者: 刘波, E-mail: bobliu(at)pku.edu.cn
  • 基金资助:
    国家自然科学基金(41572117)、中国石油化工股份有限公司科技开发部项目(P14128, P16112)和中国地质调查局项目(DD20160175-1-1)资助

Abstract:

The Lower-Middle Ordovician carbonate rocks are studied by core observation, thin section observation, geochemical analysis to restore the diagenetic evolution history of the Yubei area, Tarim Basin. Dissolution, dolomitization, silicification and cataclasis are studied and the diagenetic evolution history is divided into four stages. The grained texture dominated limestone in the relative geomorphic high location exposes to the ground and undergoes penecontemporaneous dissolution due to the fluctuation of the sea level. Caves and pores with structural selectivity parallel to the sedimentary bed are generated by the penecontemporaneous dissolution. The dolomitization developed mainly in early diagenetic stage enhances the resistance of carbonates to compaction and pressure solution, which benefits the preservation of early pores and caves. The fractures formed during the Middle-Late Caledonian and Early Hercynian in this stage are mostly closed and filled due to complicated compaction and cementation. Hydrothermal activity in middle diagenetic stage damages the reservoir slightly by the presence of pyrite and dolomite with wavy extinction and saddle structure in the reservoir space. The late diagenetic stage is characterized by the silica and calcareous fluid activity, which fill the early space partially. The development degree of fractures formed during Late Hercynian and Himalayan epoch is weaker than early diagenetic stage. However, the fractures formed during late diagenetic stage keep open due to weak diagenetic transformation and become efficient migration channel and reservoir spaces in Yubei area.

Key words: Yubei area, Lower-Middle Ordovician, carbonate, diagenetic sequence, pore

摘要:

为恢复塔里木盆地玉北地区中?下奥陶统碳酸盐岩的成岩演化历史, 通过岩芯观察、薄片观察、地球化学分析等工作, 针对溶蚀作用、白云石化作用、硅化作用和破裂作用等开展研究, 并将成岩历史划分为4个阶段。由于海平面的波动, 地貌高部位在相对海平面较低时短暂地暴露在地表, 以颗粒结构为主的灰岩在沉积后不久发生准同生溶蚀作用, 形成顺层发育的溶洞及结构选择性溶孔等。主要发育于早成岩阶段的白云石化作用增强了岩石的抗压实压溶能力, 有利于孔洞的保存; 此外, 早成岩阶段的加里东中?晚期及海西早期构造运动导致裂缝较为发育, 但由于经历了复杂的压实及胶结作用过程, 裂缝多呈封闭或充填状态, 未形成有效的储集空间。中成岩阶段的热液活动以产出具波状消光和鞍形结构的白云石和黄铁矿为特征, 热液活动总体上较弱, 对先期形成的孔洞和裂缝具有轻微的充填破坏作用。晚成岩阶段的硅质流体及钙质流体活动部分地充填早期的孔洞, 在区域内对储层具有破坏作用; 晚成岩阶段的海西晚期及喜山期裂缝活动弱于早成岩阶段的裂缝活动, 但由于经历的成岩改造作用较弱, 这些晚期裂缝多为开启状态, 在喜山期油气调整阶段具有一定的输导和储集作用。

关键词: 玉北地区, 中?下奥陶统, 碳酸盐岩, 成岩序列, 孔隙

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