| 海陆相泥页岩气体生成的半封闭模拟实验 |
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| 引用本文： | 宋董军,吴陈君,陈科,张明峰,何薇,苏龙,张东伟,付爽,妥进才.海陆相泥页岩气体生成的半封闭模拟实验[J].地球科学,2019,44(11):3639-3652. |
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| 作者姓名： | 宋董军 吴陈君 陈科 张明峰 何薇 苏龙 张东伟 付爽 妥进才 |
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| 作者单位： | 1.甘肃省油气资源研究重点实验室, 中国科学院西北生态环境资源研究院, 甘肃兰州 730000 |
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| 基金项目： | 国家自然科学基金项目41672127国家自然科学基金项目41602151国家科技重大专项2017ZX05036003-007 |
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| 摘 要： | 明确不同沉积环境下页岩气生成机理的差异性对于页岩气成因机理及页岩气地球化学特征研究具有重要意义.选择低演化阶段的海相（中元古界洪水庄组）和陆相（三叠统延长组长7段）泥页岩进行了半封闭热模拟实验，对其气体产物进行了组分和碳同位素分析.结果表明，洪水庄组页岩产气量要远远低于同温度条件下长7段泥岩的产气量.同时，长7段泥岩气体产物二次裂解程度比较高.洪水庄组页岩有机质母源以生油性为主，长7段泥岩沉积过程受到陆源混入，有机质母源以相对偏生气性为主.热模拟实验条件下黄铁矿转化成磁黄铁矿的过程也可能促进长7段泥岩烃类气的生成.热模拟实验中所用样品的状态，即柱状样或颗粒样，也可能会对气体的裂解行为产生影响.在这种情况下，南方地区页岩气高的甲烷产率以及碳同位素倒转可能与厚层页岩高的油气滞留率有关.
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| 关 键 词： | 海相页岩 陆相泥岩 半封闭模拟实验 烃类气 排烃效率 差异性 油气地质 |
| 收稿时间： | 2019-08-05 |
Gas Generation from Marine and Terrestrial Shales by Semi-Closed Pyrolysis Experiments |
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| Abstract: | Understanding differences of shale gas generation in different sedimentary environments has great significance to fully elucidate genesis mechanisms and geochemical characteristics of shale gas. In this study,semi-closed pyrolysis experiments were conducted on two lower-mature shales,including a marine shale from Hongshuizhuang Formation of Mesoproterozoic and a terrestrial mudstone from the Chang 7 Member of Yanchang Formation of Upper Triassic. The pyrolyzed gas productions were performed for gas constituent and carbon isotope analysis,aiming to investigate influences on gas generation from the nature of organic matter,mineralogical characteristics and rock fabric. The results show the discrepancy of sources of organic matter exists in the two shales,causing the amount of gas generated from Hongshuizhuang shale was lower than that of the Chang 7 Member under the same pyrolysis temperature. Meanwhile,the secondary cracking content of gas productions in the Chang 7 Member mudstone was relatively high. Organic matter in Hongshuizhuang Formation is oil-prone,but organic matter in the Chang 7 Member mudstone is relatively gas-prone due to mixture of continental materials. Moreover,the transformation process from pyrite to pyrrhotine also can be conducive to advancing the generation of hydrocarbon gas in the Chang 7 Member mudstone. The rock fabrics used in the pyrolysis experiments would lead to different cracking behaviors of gas. In this scenario,the characteristics of high methane composition and rollover of carbon isotope of shale gas in the South China may be associated with higher retention of oil and gas in those thick shales. |
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