0 引言
1 实验样品及方法
1.1 样品
1.2 烃源岩热模拟实验
1.3 烃源岩热模拟产物分析方法
2 结果与讨论
2.1 烃源岩热解气态烃组成演化特征
2.2 烃源岩热解气态烃碳同位素演化特征
2.3 烃源岩热解气中轻烃组成演化特征
表1 准噶尔盆地不同类型烃源岩热解气C7轻烃组成Table 1 Composition of C7 light hydrocarbon of pyrolysis gas from different types of source rocks in Junggar Basin |
| 热解温度/℃ | 石炭系烃源岩C7轻烃/% | 佳木河组烃源岩C7轻烃/% | 风城组烃源岩C7轻烃/% | 平地泉组烃源岩C7轻烃/% | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| nC7 | ΣDMCP | MCH | nC7 | ΣDMCP | MCH | nC7 | ΣDMCP | MCH | nC7 | ΣDMCP | MCH | |
| 300 | 33.21 | 17.31 | 49.49 | 37.85 | 18.94 | 43.21 | 45.91 | 17.64 | 36.45 | 45.30 | 18.81 | 35.89 |
| 350 | 32.34 | 14.78 | 52.88 | 40.21 | 16.35 | 43.44 | 49.41 | 16.81 | 33.78 | 45.97 | 18.06 | 35.97 |
| 400 | 36.42 | 14.20 | 49.38 | 37.62 | 16.38 | 46.00 | 49.27 | 16.41 | 34.32 | 46.36 | 17.06 | 36.58 |
| 450 | 32.72 | 14.07 | 53.21 | 39.89 | 14.18 | 45.93 | 49.98 | 13.82 | 36.20 | 47.88 | 16.98 | 35.14 |
| 500 | 35.83 | 12.78 | 51.39 | 36.55 | 14.74 | 48.71 | 49.30 | 12.84 | 37.87 | 48.51 | 15.34 | 36.15 |
|
图5 准噶尔盆地烃源岩不同温度热解气轻烃组成(a)烃源岩热解气C7轻烃中正庚烷含量;(b)烃源岩热解气C7轻烃中甲基环己烷含量;(c)烃源岩热解气C7轻烃中二甲基环戊烷含量;(d)烃源岩热解气C5—C7正构烷烃含量;(e)烃源岩热解气C5—C7异构烷烃含量;(f)烃源岩热解气C5—C7环烷烃含量 Fig.5 Light hydrocarbon composition of pyrolysis gas from source rocks at different temperatures in the Junggar Basin |
2.4 烃源岩热解气轻烃碳同位素演化特征
表2 准噶尔盆地不同类型烃源岩热解气轻烃碳同位素组成Table 2 Carbon isotope of light hydrocarbon of pyrolysis gas from different types of source rocks in the Junggar Basin |
| 热解温度/℃ | 烃源岩 | 轻烃化合物碳同位素/‰(VPDB) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| iC5 | nC5 | 3MC5 | nC6 | Bz | CYC6 | 3MC6 | nC7 | MCYC6 | TOL | ||
| 300 | 风城组 | -32.4 | -30.2 | -31.1 | -32.1 | -27.1 | -29.0 | -33.1 | -31.5 | -28.0 | -27.9 |
| 350 | -32.0 | -30.8 | -31.8 | -33.2 | -26.9 | -27.2 | -33.8 | -30.8 | -28.7 | -26.3 | |
| 400 | -31.4 | -29.9 | -33.1 | -28.9 | -27.1 | -28.3 | -33.1 | -30.7 | -28.4 | -26.9 | |
| 450 | -32.0 | -30.8 | -32.7 | -30.7 | -25.5 | -27.9 | -31.2 | -29.5 | -28.2 | -25.5 | |
| 500 | -31.6 | -30.3 | -29.8 | -29.6 | -25.1 | -27.8 | -31.1 | -28.9 | -29.1 | -25.6 | |
| 300 | 芦草沟组 | -29.9 | -29.7 | -33.1 | -30.4 | -27.9 | -27.0 | -31.1 | -31.9 | -29.6 | -28.6 |
| 350 | -30.5 | -28.4 | -31.2 | -33.6 | -27.2 | -26.4 | -32.1 | -30.3 | -29.1 | -26.3 | |
| 400 | -31.0 | -29.1 | -31.7 | -30.9 | -28.5 | -29.6 | -32.1 | -30.8 | -28.6 | -26.8 | |
| 450 | -30.2 | -31.1 | -30.3 | -30.0 | -28.7 | -29.3 | -30.4 | -30.3 | -27.1 | -26.9 | |
| 500 | -29.9 | -30.4 | -31.1 | -32.1 | -26.6 | -27.8 | -31.3 | -30.9 | -28.4 | -26.0 | |
| 300 | 佳木河组 | -25.6 | -24.3 | -26.3 | -26.4 | -19.3 | -24.3 | -25.9 | -24.3 | -24.8 | -20.1 |
| 350 | -26.9 | -24.8 | -28.6 | -25.6 | -20.6 | -25.6 | -23.5 | -23.8 | -25.8 | -21.1 | |
| 400 | -25.2 | -24.4 | -25.6 | -25.2 | -19.6 | -24.1 | -25.8 | -23.9 | -23.9 | -22.7 | |
| 450 | -23.2 | -24.4 | -25.3 | -24.6 | -20.8 | -24.9 | -23.4 | -24.4 | -22.1 | -22.2 | |
| 500 | -24.4 | -23.0 | -24.7 | -24.0 | -19.7 | -24.5 | -23.9 | -24.5 | -24.3 | -21.7 | |
| 300 | 石炭系 | -25.6 | -24.3 | -27.4 | -25.4 | -20.5 | -23.2 | -27.2 | -26.2 | -25.6 | -22.9 |
| 350 | -25.0 | -22.3 | -26.4 | -24.7 | -22.2 | -24.7 | -27.1 | -25.9 | -26.0 | -22.8 | |
| 400 | -26.3 | -25.8 | -24.6 | -24.9 | -22.0 | -21.9 | -28.1 | -24.4 | -25.8 | -21.1 | |
| 450 | -25.1 | -24.5 | -24.3 | -23.9 | -21.8 | -23.3 | -26.2 | -23.3 | -24.6 | -20.4 | |
| 500 | -23.3 | -24.1 | -25.2 | -23.3 | -19.3 | -21.5 | -25.5 | -23.5 | -22.9 | -19.1 | |
|
图7 准噶尔盆地烃源岩不同温度热解气中链烷烃碳同位素组成(a)不同类型烃源岩热解气中3-甲基戊烷碳同位素随温度变化;(b)不同类型烃源岩热解气中3-甲基己烷碳同位素随温度变化; (c)不同类型烃源岩热解气中正己烷碳同位素随温度变化;(d)不同类型烃源岩热解气中正庚烷碳同位素随温度变化 Fig.7 Carbon isotopic of alkanes in pyrolysis gas from source rocks at different temperatures in the Junggar Basin |
图9 准噶尔盆地不同类型烃源岩热解气轻烃碳同位素组成特征(a)风城组烃源岩热解气轻烃碳同位素组成;(b)佳木河组烃源岩热解气轻烃碳同位素组成; (c)平地泉组烃源岩热解气轻烃碳同位素组成;(d)石炭系烃源岩热解气轻烃碳同位素组成;注:3MC5—3-甲基戊烷;nC6—正己烷;Bz—苯;CYC6—环己烷;3MC6—3-甲基己烷;nC7—正庚烷;MCYC6—甲基环己烷;TOL—甲苯 Fig.9 Carbon isotope of light hydrocarbons in pyrolysis gas from different types of source rocks in the Junggar Basin |
2.5 轻烃碳同位素在准噶尔盆地南缘地区的应用
图11 准噶尔盆地不同类型烃源岩热解气与南缘深层天然气轻烃碳同位素划分图版(a)3-甲基环戊烷与3-甲基环己烷碳同位素划分图版;(b)正己烷与正庚烷碳同位素划分图版; (c)环己烷与甲基环己烷碳同位素划分图版;(d)苯与甲苯碳同位素划分图版 Fig.11 Classification chart of carbon isotope of light hydrocarbons in pyrolysis gas from different types of source rocks and deep gas from middle part of southern margin of Junggar Basin |
3 结论
(2)风城组和平地泉组烃源岩热解气轻烃中正庚烷占优势,相对含量大于40%,C5-7正构烷烃含量大于40%,为腐泥型气特征,石炭系和二叠系佳木河组烃源岩热解气轻烃中甲基环己烷占优势,相对含量大于40%,C5-7正构烷烃含量小于40%,为腐殖型气特征。

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