Acta Petrolei Sinica ›› 2022, Vol. 43 ›› Issue (5): 595-604.DOI: 10.7623/syxb202205002

• PETROLEUM EXPLORATION • Previous Articles     Next Articles

Genesis analysis of the petroleum associated H2S: a case study of Pengyang oilfield in Ordos Basin

Shang Ting1, Tian Jingchun2, Liu Xin2,3, Xie Xiankui4, Zhang Xiaolei3, Yu Wei2, Guo Yixuan3, Wang Feng2, Chen Jiangmeng5   

  1. 1. School of Resources, Environment and Historical Culture, Xianyang Normal University, Shaanxi Xianyang 712000, China;
    2. Institute of Sedimentary Geology, Chengdu University of Technology, Sichuan Chengdu 610059, China;
    3. Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company, Shaanxi Xi'an 710018, China;
    4. Exploration Utility Department, PetroChina Changqing Oilfield Company, Shaanxi Xi'an 710018, China;
    5. NO. 2 Gas Production Plant, PetroChina Changqing Oilfield Company, Shaanxi Xi'an 710200, China
  • Received:2020-10-20 Revised:2021-12-28 Published:2022-05-28

石油伴生H2S的成因分析——以鄂尔多斯盆地彭阳油田为例

尚婷1, 田景春2, 刘鑫2,3, 谢先奎4, 张晓磊3, 余威2, 郭懿萱3, 王峰2, 陈江萌5   

  1. 1. 咸阳师范学院资源环境与历史文化学院 陕西咸阳 712000;
    2. 成都理工大学沉积地质研究院 四川成都 610059;
    3. 中国石油长庆油田公司勘探开发研究院 陕西西安 710018;
    4. 中国石油长庆油田公司勘探事业部 陕西西安 710018;
    5. 中国石油长庆油田公司第二采气厂 陕西西安 710200
  • 通讯作者: 刘鑫,男,1982年5月生,2007年获西北大学硕士学位,现为中国石油长庆油田公司勘探开发研究院高级工程师,主要从事油气勘探地质研究工作。Email:19019273@qq.com
  • 作者简介:尚婷,女,1981年5月生,2012年获西北大学博士学位,现为咸阳师范学院高级工程师,主要从事沉积学教学及非固体矿产地质研究工作。Email:84524325@qq.com
  • 基金资助:
    国家科技重大专项"大型油气田及煤层气开发"(2016ZX05050、2017ZX05001-002-008)和中国石油天然气股份有限公司科技重大专项(2016E-0501)资助。

Abstract: Pengyang oilfield is a newly explored oilfield with low H2S content in Ordos Basin. Its main oil-producing layer is Jurassic Yan'an Formation, and the content of the petroleum associated H2S is up to 0.115%. To clarify the H2S generation mechanism is of great significance for rational development and safe production of the oilfield. Based on the systematic analysis of sulfides in reservoir and sulfur isotopes in oilfield water, the paper predicts the origin of petroleum associated H2S in the Jurassic Yan'an Formation. Yan'an Formation is dominated by lumpy, spotted, patched and star-pointed pyrites, of which δ34S value ranges from -1.9 ‰ to 10.1 ‰. Among them, patched and lumpy pyrites are rapidly crystallized in the early sedimentation period, while spotted and star-pointed pyrites are deposited due to the reduction by sulfate reducing bacteria. The δ34S value of gypsum ranges from 16.8 ‰ to 17.7 ‰, indicating that it is the product in the later diagenetic stage and is not the source of sulfur element of H2S. The δ34S value of oilfield water is relatively high, with an average of 37.9 ‰. The reason for this is that 32S in the formation water is consumed by the reduction of sulfate reducing bacteria, and thus 34S is relatively rich in the water body. The late dissolution of pyrite and the reduction of organic sulfide by sulfate reducing bacteria can generate SO42-, by which the oil reservoir water of the Jurassic system possessed a high concentration of SO42- and provided a sufficient material basis for H2S generation. Physical and chemical conditions of the Jurassic formation water such as salinity, pH value and formation temperature were conducive to the survival of sulfate reducing bacteria and offered a suitable reaction zone for the reduction of sulfate reducing bacteria. The comprehensive analysis indicates that the petroleum associated H2S of the Jurassic system in Pengyang oilfield is the product of the reduction of sulfate reducing bacteria.

Key words: hydrogen sulfide, sulfur isotope, reduction of sulfate reducing bacteria, Pengyang oilfield, Ordos Basin

摘要: 彭阳油田是鄂尔多斯盆地新探明的低H2S含量的油田,其主力产层为侏罗系延安组,原油伴生H2S含量最高为0.115%,明确H2S成因机制对于油田合理开发及安全生产具有重要意义。基于储层硫化物及油田水硫同位素的系统分析,预测了侏罗系延安组原油伴生H2S的成因。延安组主要发育集块状、斑点状、斑块状、星点状等黄铁矿类型,其δ34S值为-1.9 ‰~10.1 ‰,其中,斑块状、集块状黄铁矿为沉积早期快速结晶成因,斑点状、星点状黄铁矿为硫酸盐还原菌还原作用成因。石膏的δ34S值在16.8 ‰~17.7 ‰,为后期成岩阶段的产物,其并非H2S的硫元素来源。油田水的δ34S值较高,平均为37.9 ‰,这主要是由于硫酸盐还原菌还原作用消耗地层水中的32S,使水体相对富集34S。黄铁矿后期溶解和硫酸盐还原菌还原有机硫化物均可释放SO42-,使侏罗系油田水具有较高的SO42-浓度,为H2S的生成提供了充足的物质基础。侏罗系地层水的矿化度、pH值及地层温度等物理化学条件均利于硫酸盐还原菌的生存,为硫酸盐还原菌还原作用提供了适宜的反应场所。综合分析认为,彭阳油田侏罗系原油伴生H2S为硫酸盐还原菌还原成因。

关键词: 硫化氢, 硫同位素, 硫酸盐还原菌还原作用, 彭阳油田, 鄂尔多斯盆地

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