Acta Petrolei Sinica ›› 2022, Vol. 43 ›› Issue (2): 250-261.DOI: 10.7623/syxb202202007

• PETROLEUM EXPLORATION • Previous Articles     Next Articles

Genesis of hydrogen sulfide in Ordovician Majiagou Formation, mid-eastern Ordos Basin: evidence from fluid inclusions

Wu Xiaoli1, Xu Wanglin2, Li Rongxi1, Li Ningxi2, Liu Qi1, Zhao Di1, Zhao Bangsheng1, Qin Xiaoli1, Bai Ying2   

  1. 1. School of Earth Science and Resource, Chang'an University, Shaanxi Xi'an 710054, China;
    2. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China
  • Received:2021-03-01 Revised:2021-08-25 Published:2022-03-03

鄂尔多斯盆地中东部奥陶系马家沟组硫化氢成因——来自流体包裹体的证据

吴小力1, 徐旺林2, 李荣西1, 李宁熙2, 刘齐1, 赵迪1, 赵帮胜1, 覃小丽1, 白莹2   

  1. 1. 长安大学地球科学与资源学院 陕西西安 710054;
    2. 中国石油勘探开发研究院 北京 100083
  • 通讯作者: 李荣西,男,1966年6月生,1998年获中国矿业大学(北京)煤田、油气地质与勘探专业博士学位,现为长安大学地球科学与资源学院院长、教授,主要从事地质流体和油气地质勘探综合研究。Email:rongxi99@163.com
  • 作者简介:吴小力,男,1989年8月生,2018年获长安大学油气田地质与开发专业博士学位,现为长安大学地球科学与资源学院讲师,主要从事沉积学及油气成藏地质学研究。Email:wxlgeo@163.com
  • 基金资助:
    国家自然科学基金项目(No.41772118)和陕西省自然科学基金项目(No.211427210238)资助。

Abstract: The genesis of hydrogen sulfide is of great significance for understanding the natural gas accumulation in carbonate reservoirs. In this study, core samples are taken from Well Tao112 in mid-eastern Ordos Basin. Through the systematic sample collection, thin section polish, petrography observation of fluid inclusions, cathode-luminescence analysis, microthermometry and laser Raman spectroscopy test of fluid inclusions, this paper analyzes the genetic type and forming mechanism of hydrogen sulfide, and explores the characteristics of natural gas accumulation at the middle and lower assemblages of Majiagou Formation. The results show that the original abundance of hydrogen sulfide of Majiagou Formation in Well Tao112 is significantly greater than 5%, and its formation temperature is 160-220℃, so the hydrogen sulfide is the product of thermochemical sulfate reduction (TSR). In the TSR, the gypsum-salt rock section in Majiagou Formation is the main source of sulfate minerals. The natural gas from the Upper Paleozoic coal-measure source rock and the marine source rock of Ordovician Majiagou Formation may provide hydrocarbon sources for hydrogen sulfide generation. The high reaction temperature and formation pressure difference ensure the occurrence and continuation of TSR.

Key words: hydrogen sulfide, fluid inclusion, natural gas accumulation, Ordovician, Majiagou Formation, Ordos Basin

摘要: 硫化氢成因对认识碳酸盐岩型天然气的成藏问题具有重要意义。以鄂尔多斯盆地中东部地区Tao112井马家沟组岩心样品为研究对象,通过系统采样、薄片制备、流体包裹体岩相学观察、阴极发光分析、显微测温和流体包裹体激光拉曼光谱测试,分析了研究区硫化氢的成因类型和形成机制,探讨了马家沟组中、下组合天然气的成藏特征。结果表明,Tao112井马家沟组中硫化氢的原始丰度明显大于5%,形成温度在160~220℃,为热化学硫酸盐还原(TSR)反应成因。在马家沟组发生的TSR反应中,马家沟组中的膏盐岩段是最主要的硫酸盐矿物来源;上古生界煤系烃源岩和奥陶系马家沟组海相烃源岩生成的天然气可能提供了生成硫化氢所需的烃类供应条件;较高的反应温度和地层压力差保证了TSR反应的发生和持续。

关键词: 硫化氢, 流体包裹体, 天然气成藏, 奥陶系, 马家沟组, 鄂尔多斯盆地

CLC Number: