| 塔中地区奥陶系喜马拉雅山期S干气充注的证据 |
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| 引用本文： | 何宏,李红霞,张科,陶小晚,蔡春芳.塔中地区奥陶系喜马拉雅山期S干气充注的证据[J].地质科学,2014,49(4):1327-1336. |
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| 作者姓名： | 何宏 李红霞 张科 陶小晚 蔡春芳 |
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| 作者单位： | 1. 中国石化股份有限公司北京石油勘探开发研究院 北京 100083;
2. 中国科学院地质与地球物理研究所 油气资源重点实验室 北京 100029;
3. 中国石油塔里木油田分公司勘探开发研究院 新疆库尔勒 8410000;
4. 中国石油勘探开发研究院 北京 100083 |
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| 摘 要： | 塔中地区奥陶系天然气成因多样；Ⅰ号坡折带中东部奥陶系天然气以高干燥系数、 甲烷同位素值重为特征；与塔深1井寒武系原油裂解气接近；应主要来自寒武系原油裂解气成因。寒武系贫H2S、 高成熟原油裂解气在喜马拉雅山期时；气侵奥陶系油气藏；得到了以下主要证据的支持: 1）天然气甲烷δ13C值大多比Chung et al.（1988）天然气模式甲烷δ13C值计算值高3‰以上；2）干燥系数与甲烷δ13C值大体上具有正相关关系；3）天然气干燥系数与H2S含量大体上具有负相关关系。这些特征表明；存在贫H2S、 相对富13C甲烷为主的干气与富H2S、 相对贫13C甲烷的湿气混合作用。奥陶系中H2S-δ34S 值为14‰～20‰；远低于中深1井寒武系原地热化学硫酸盐还原作用（TSR）成因的H2S（33‰）；支持了奥陶系中H2S并不是来源于寒武系古油气藏。于是提出；来自寒武系贫H2S的干气在喜马拉雅山期对良里塔格组和鹰山组油气藏发生了气洗；油气藏的气/油比值增大、 导致了原油蜡含量增高、 甲烷δ13C值发生正偏移。
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| 关 键 词： | 甲烷 碳同位素 气洗 原油蜡 塔里木盆地 |
| 收稿时间： | 2013-10-30 |
| 修稿时间： | 2013-10-30; |
Evidence for late charge of H2S-poor dry gas in the Ordovician in Tazhong area |
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| He Hong,Li Hongxia,Zhang Ke,Tao Xiaowan,Cai Chunfang.Evidence for late charge of H2S-poor dry gas in the Ordovician in Tazhong area[J].Chinese Journal of Geology,2014,49(4):1327-1336. |
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| Authors: | He Hong Li Hongxia Zhang Ke Tao Xiaowan Cai Chunfang |
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| Institution: | 1. Institute of Petroleum Exploration and Development, SINOPEC, Beijing 100083;
2. Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029;
3. Research Institute of Petroleum Exploration and Development, Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000;
4. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083 |
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| Abstract: | Natural gases in the Ordovician of Tazhong area show very different geochemical characteristics. The gas in the middle and east part of the No.1 fault-slope zone is characterized by high gas dryness coefficient and δ13C isotope value, and is similar to the oil-cracking gas in the Cambrian in well TS1. The gas from the Cambrian was H2S-poor and charged into the petroleum pools of the middle and east part during the Himalayan orogeny, which is supported by the following lines of evidence: 1)the gas has methane δ13C value of about 3‰ higher than anticipated from the natural gas plot by Chung et al.(1988); 2)a linear relationship between gas dryness coefficient and its δ13C value; and 3)a inverse linear relationship between gas dryness and the concentration of H2S. These features suggest that there exists a mixing between H2S-poor, 13C-rich methane-dominated dry gas and H2S-rich, 13 C-poor wet gas. H2S in the Ordovician has δ34S values from 14‰～20‰, being significantly lighter than the H2S in the ZS1(33‰), supporting the different origin. The charge of the Cambrian dry gas may have resulted in increase in gas/oil ratios and wax content, gas dryness coefficient and positive shift in methane δ13C value. |
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| Keywords: | methane carbon isotope gas washing oil wax Tarim Basin |
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