特种油气藏 ›› 2022, Vol. 29 ›› Issue (4): 62-68.DOI: 10.3969/j.issn.1006-6535.2022.04.008

• 地质勘探 • 上一篇    下一篇

鄂尔多斯盆地东缘本溪组8#煤层方解石脉体成因

王成旺1,2, 徐凤银1,2, 甄怀宾1,2, 陈高杰1,2, 甯波3, 曹铮4, 陈岑4   

  1. 1.中联煤层气国家工程研究中心有限责任公司,北京 100095;
    2.中国石油煤层气有限责任公司,北京 100020;
    3.中国石油勘探开发研究院,北京 100083;
    4.重庆科技学院,重庆 401331
  • 收稿日期:2021-09-14 修回日期:2022-05-31 出版日期:2022-08-25 发布日期:2023-01-09
  • 作者简介:王成旺(1984—),男,高级工程师,2008年毕业于中国石油大学(华东)资源勘查工程专业,2011年毕业于该校矿产普查与勘探专业,获硕士学位,现从事煤层气开发地质工程一体化研究工作。
  • 基金资助:
    中国石油科技重大专项“中低煤阶煤层气开发增产技术研究”(2017E-1403);国家自然科学基金“松辽盆地南部泉四段致密砂岩深部无机CO2多期充注及储层改造机制”(42102187);国家科技重大专项“煤层气高效增产与排采关键技术研究”(2016ZX05042);“鄂东缘深层煤层气与煤系地层天然气整体开发示范工程”(2016ZX05065);重庆市自然科学基金面上项目“定量表征的断层活动对页岩含气量的控制”(cstc2020jcyj-msxmX0869)

Genesis of Calcite Veins in 8# Coal Bed of Benxi Formation on Eastern Margin of Ordos Basin

Wang Chengwang1,2, Xu Fengyin1,2, Zhen Huaibin1,2, Chen Gaojie1,2, Ning Bo3, Cao Zheng4, Chen Cen4   

  1. 1. National Engineering Research Center, China United Coalbed Methane Corporation Ltd., Beijing 100095, China;
    2. PetroChina Coalbed Methane Co., Ltd., Beijing 100020, China;
    3. Research Institute of Petroleum Exploration & Development, Beijing 100083, China;
    4. Chongqing University of Science & Technology, Chongqing 401331, China
  • Received:2021-09-14 Revised:2022-05-31 Online:2022-08-25 Published:2023-01-09

摘要: 针对鄂尔多斯盆地东缘本溪组8#煤层方解石脉体成因不清的问题,综合运用显微岩相学、同位素地球化学和流体包裹体等方法,开展方解石脉发育期次分析以明确成脉流体来源和形成时间。研究结果表明,研究区8#煤层中发育2期方解石脉体(C1和C2),C1方解石脉的成岩流体主要为源于围岩母岩的地层卤水和富生物气有机流体,C2方解石脉的流体来源主要与有机质脱羧作用形成的液态烃类流体有关,同时C1和C2方解石脉的形成均受到早白垩世构造热事件导致的深部热液流体影响。结合研究区烃类成藏史和埋藏史分析,明确C1方解石脉的形成时间在晚三叠世—早侏罗世期间,C2脉体形成时间为晚侏罗世—早白垩世。结合研究区8#煤层勘探生产实践,方解石脉发育区域煤层气富集程度较高,具有良好的勘探开发前景。研究成果对于煤层气富集区域的勘探具有重要的参考意义。

关键词: 方解石脉体, 成脉流体来源, 成脉时间, 煤层, 鄂尔多斯盆地

Abstract: In view of the unclear genesis of calcite veins in 8# Coal Bed of Benxi Formation on Eastern Margin of Ordos Basin, the calcite vein development stages were analyzed to determine the source and formation time of vein-forming fluids by micro petrography, isotope geochemistry, fluid inclusion and other methods. The study results indicated that calcite veins (C1 and C2) in Stage 2 were developed in 8# coalbed in the study area, the diagenetic fluids of C1 calcite veins were mainly stratigraphic brine and biogas-rich organic fluids from surrounding rock and parent rock, the diagenetic fluids of C2 calcite veins were mainly liquid hydrocarbon fluids formed by the decarboxylation of organic matter, and meanwhile the formation of C1 and C2 calcite veins was affected by deep hydrothermal fluid formed by Early Cretaceous tectonic thermal events. Combined with the analysis of the hydrocarbon formation and burial history in the study area, it was clear that C1 calcite veins were formed from Late Triassic to Early Jurassic and C2 veins were formed from Late Jurassic to Early Cretaceous. Production of 8# coalbed in the study area, the calcite vein development area had a high degree of CBM enrichment, indicating bright prospects for exploration and development. The study results provide an important reference for the exploration of CBM-rich areas.

Key words: calcite vein body, vein-forming fluid source, vein forming time, coalbed, Ordos Basin

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