0 引言
1 实验与样品
1.1 样品
表 1 干酪根地球化学组成Table 1 The geochemical compositions of kerogen |
层组 | TOC /% | T max /℃ | S 1 /(mg/g) | S 2 /(mg/g) | I H /(mg/gTOC) | I O /(mg/gTOC) | 干酪根样 | ||
---|---|---|---|---|---|---|---|---|---|
H/C | O/C | S/C | |||||||
玉尔吐斯组 | 8.45 | 492 | 0.33 | 4.63 | 54.79 | 2.01 | 0.62 | 0.08 | 0.08 |
1.2 金管模拟实验
表2 模拟实验气体产物产率、组成与碳氢同位素特征Table 2 The yields, chemical and isotopic compositions of gas products in pyrolysis experiments |
温度 /℃ | 时间 /d | Easy% R 0 /% | 气体产率/(mL/gTOC) | 碳同位素 /‰(VPDB) | 氢同位素 /‰(VSMOW) | 含水体质种类 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
C1 | C2 | C3 | iC4 | nC4 | iC5 | nC5 | H2 | CO2 | H2S | δ13C1 | δ13C2 | δ13C | δD1 | ||||
330 | 1 | 0.79 | 0.086 | 0.005 | — | — | — | — | — | — | 14.05 | — | — | — | -29.2 | — | 干 酪 根 + 水 |
330 | 7 | 1.05 | 0.067 | 0.004 | — | — | — | -— | — | — | 10.08 | — | — | — | -29.1 | — | |
330 | 10 | 1.11 | 0.223 | 0.048 | 0.014 | 0.001 0 | 0.001 1 | 0.000 2 | 0.000 2 | — | 22.54 | — | — | -24.5 | -29.1 | -274.7 | |
360 | 1 | 1.02 | 0.189 | 0.015 | 0.002 | 0.000 3 | 0.000 4 | 0.000 3 | 0.000 4 | — | 19.17 | — | — | -24.4 | -29.8 | -269.1 | |
360 | 5 | 1.29 | 0.572 | 0.028 | 0.002 | 0.000 3 | 0.000 4 | 0.000 4 | 0.000 6 | — | 26.41 | — | -45.4 | -25.3 | -29.3 | -272.2 | |
360 | 7 | 1.42 | 0.957 | 0.045 | 0.002 | 0.000 4 | 0.000 4 | 0.000 2 | 0.000 3 | — | 27.77 | — | -44.0 | -26.2 | -29.1 | -275.3 | |
360 | 10 | 1.5 | 0.715 | 0.029 | 0.001 | 0.000 3 | 0.000 3 | 0.000 3 | 0.000 1 | — | 20.96 | — | -45.6 | -26.4 | -29.3 | -266.6 | |
380 | 1 | 1.24 | 0.437 | 0.027 | 0.001 | 0.000 4 | 0.000 4 | 0.000 2 | 0.000 2 | — | 20.79 | — | -47.8 | -25.9 | -29.5 | -266.9 | |
380 | 5 | 1.56 | 0.721 | 0.029 | 0.000 | 0.000 3 | 0.000 3 | 0.000 4 | 0.000 4 | — | 11.09 | 0.01 | -46.4 | -25.6 | -29.4 | -273.5 | |
380 | 7 | 1.72 | 2.419 | 0.100 | 0.002 | 0.000 5 | 0.000 5 | 0.000 7 | 0.000 3 | 0.008 | 27.86 | 0.30 | -43.5 | -25.1 | -29.6 | -282.1 | |
380 | 10 | 1.82 | 3.471 | 0.130 | 0.002 | 0.000 4 | 0.000 3 | 0.000 2 | 0.000 2 | 0.006 | 30.21 | 0.81 | 42.3 | -24.8 | -29.0 | -280.8 | |
400 | 1 | 1.49 | 1.019 | 0.051 | 0.003 | 0.000 3 | 0.000 2 | 0.000 3 | 0.000 3 | 0.006 | 24.17 | 0.08 | -41.3 | -24.6 | -29.1 | -276.6 | |
400 | 5 | 1.88 | 5.446 | 0.174 | 0.005 | 0.000 2 | 0.000 2 | 0.001 5 | 0.003 3 | 0.005 | 31.33 | 0.40 | -38.5 | -25.1 | -28.7 | -279.6 | |
400 | 7 | 2.07 | 6.682 | 0.215 | 0.003 | 0.004 4 | 0.003 7 | 0.015 4 | 0.008 1 | 0.017 | 31.50 | 2.63 | -38.1 | -24.5 | -28.7 | -275.0 | |
400 | 10 | 2.19 | 10.995 | 0.312 | 0.006 | 0.005 3 | 0.008 0 | 0.008 9 | 0.006 7 | 0.005 | 38.64 | 5.76 | -37.9 | -24.7 | -29.0 | -255.8 | |
450 | 1 | 2.31 | 10.334 | 0.380 | 0.009 | 0.001 2 | 0.002 0 | 0.001 5 | 0.001 1 | 0.062 | 40.74 | 9.35 | -37.7 | -24.6 | -28.6 | -251.4 | |
450 | 5 | 2.84 | 22.527 | 0.489 | 0.012 | 0.000 5 | 0.000 7 | 0.005 0 | 0.003 9 | 1.113 | 54.23 | 13.91 | -34.8 | -23.6 | -27.7 | -184.5 | |
450 | 7 | 3.08 | 27.419 | 0.547 | 0.014 | 0.000 5 | 0.000 4 | 0.016 1 | 0.005 1 | 1.474 | 60.43 | 14.79 | -33.6 | -23.2 | -28.0 | -165.3 | |
330 | 1 | 0.79 | 0.056 | 0.005 | — | — | — | — | — | — | 10.10 | — | — | — | -29.1 | — | 干 酪 根 + 黄 铁 矿 + 水 |
330 | 5 | 0.95 | 0.083 | 0.005 | — | — | — | — | — | — | 13.26 | — | — | — | -28.5 | — | |
330 | 7 | 1.05 | 0.113 | 0.004 | — | — | — | — | — | — | 20.08 | — | — | — | -28.8 | — | |
330 | 10 | 1.11 | 0.112 | 0.003 | — | — | — | — | — | — | 21.28 | — | — | — | -28.5 | -252.4 | |
360 | 1 | 1.02 | 0.200 | 0.011 | — | — | — | — | — | — | 17.25 | — | -46.2 | -26.4 | — | -256.7 | |
360 | 5 | 1.29 | 0.345 | 0.007 | 0.001 | — | — | — | — | — | 23.05 | — | -45.2 | -26.2 | -28.4 | -263.2 | |
360 | 7 | 1.42 | 0.343 | 0.005 | 0.001 | — | — | — | — | — | 22.03 | — | -43.1 | -25.8 | -27.9 | -260.3 | |
360 | 10 | 1.5 | 0.619 | 0.007 | 0.003 | 0.000 3 | 0.000 5 | 0.000 2 | 0.000 1 | — | 38.68 | — | -41.5 | -25.7 | -27.5 | -269.1 | |
380 | 1 | 1.24 | 0.400 | 0.018 | 0.006 | 0.000 3 | 0.000 6 | 0.000 6 | 0.000 4 | — | 23.01 | — | -43.9 | -25.4 | -28.8 | -266.8 | |
380 | 5 | 1.56 | 0.912 | 0.023 | 0.016 | 0.003 1 | 0.004 8 | 0.005 5 | 0.005 7 | — | 33.42 | — | -42.6 | -25.1 | -28.7 | -265.4 | |
380 | 7 | 1.72 | 0.961 | 0.010 | 0.003 | 0.001 3 | 0.002 0 | 0.002 1 | 0.002 4 | — | 35.99 | — | -42.5 | -25.2 | -28.6 | -260.8 | |
380 | 10 | 1.82 | 1.422 | 0.011 | 0.003 | 0.001 0 | 0.001 3 | 0.002 1 | 0.003 2 | 0.006 | 47.51 | — | -39.9 | -26.4 | -29.1 | -265.4 | |
400 | 1 | 1.49 | 0.798 | 0.061 | 0.049 | 0.017 7 | 0.021 7 | 0.001 4 | 0.006 0 | 0.005 | 27.20 | — | -40.6 | -26.1 | -29.5 | -266.8 | |
400 | 5 | 1.88 | 2.233 | 0.020 | 0.011 | 0.006 0 | 0.007 7 | 0.010 2 | 0.003 9 | 0.007 | 39.81 | — | -39.8 | -24.6 | -28.7 | -265.1 | |
400 | 7 | 2.07 | 3.088 | 0.019 | 0.004 | 0.002 5 | 0.003 3 | 0.002 9 | 0.002 3 | 0.007 | 44.61 | — | -37.8 | -25.1 | -28.6 | -261.5 | |
400 | 10 | 2.19 | 2.848 | 0.015 | 0.005 | 0.001 9 | 0.002 3 | 0.003 3 | 0.002 8 | 0.006 | 45.04 | — | -37.4 | -25.9 | -28.5 | -256.4 | |
450 | 1 | 2.31 | 5.857 | 0.052 | 0.009 | 0.000 4 | 0.000 4 | 0.000 9 | 0.000 7 | 0.000 | 50.13 | 0.06 | -37.0 | -25.8 | -28.6 | -241.7 | |
450 | 5 | 2.84 | 8.387 | 0.044 | 0.007 | 0.000 3 | 0.000 3 | 0.001 4 | 0.001 0 | 0.357 | 76.85 | 11.10 | -32.4 | -24.2 | -28.4 | -168.4 | |
450 | 7 | 3.08 | 18.935 | 0.188 | 0.006 | 0.000 4 | 0.000 4 | 0.713 | 64.84 | 31.55 | -31.8 | -24.1 | -28.2 | -155.6 | |||
330 | 1 | 0.79 | 0.083 | 0.005 | 0.001 | 0.000 2 | 0.000 4 | 0.000 2 | 0.000 1 | — | 5.60 | — | — | -31.0 | -30.7 | — | 干 酪 根 + 磁 铁 矿 + 水 |
330 | 5 | 0.95 | 0.132 | 0.006 | 0.000 | 0.000 6 | 0.000 9 | 0.002 8 | 0.000 8 | — | 7.46 | — | — | -29.4 | -30.4 | — | |
330 | 7 | 1.05 | 0.138 | 0.007 | 0.001 | 0.000 9 | 0.001 1 | 0.002 8 | 0.001 2 | — | 8.17 | — | -29.3 | -30.1 | |||
330 | 10 | 1.11 | 0.186 | 0.009 | 0.000 | 0.000 7 | 0.000 8 | 0.001 6 | 0.001 9 | — | 8.24 | — | — | -29.8 | -30.0 | ||
360 | 1 | 1.02 | 0.231 | 0.012 | 0.001 | 0.000 6 | 0.000 6 | 0.002 0 | 0.000 8 | — | 6.26 | — | -48.6 | -31.2 | -30.4 | -262.7 | |
360 | 5 | 1.29 | 0.538 | 0.018 | 0.001 | 0.000 4 | 0.000 4 | 0.001 1 | 0.001 2 | — | 8.91 | — | -47.1 | -28.6 | -30.1 | -281.1 | |
360 | 7 | 1.42 | 0.774 | 0.021 | 0.001 | 0.000 3 | 0.000 3 | 0.005 4 | 0.002 5 | — | 13.76 | — | -45.8 | -25.4 | -30.0 | -276.8 | |
360 | 10 | 1.5 | 0.814 | 0.022 | 0.002 | 0.002 1 | 0.001 9 | 0.000 5 | 0.002 5 | — | 11.01 | — | -44.9 | -25.8 | -30.1 | -275.1 | |
380 | 1 | 1.24 | 0.525 | 0.021 | 0.001 | 0.000 6 | 0.000 5 | 0.000 2 | 0.000 4 | — | 7.09 | — | -43.9 | -26.0 | -30.4 | -276.3 | |
380 | 5 | 1.56 | 1.475 | 0.029 | 0.005 | 0.001 8 | 0.001 7 | 0.000 3 | 0.000 4 | — | 18.00 | — | -42.3 | -24.3 | -30.0 | -276.6 | |
380 | 7 | 1.72 | 1.940 | 0.046 | 0.001 | — | — | — | — | 0.004 | 11.03 | — | -42.6 | -23.8 | -30.2 | -289.1 | |
380 | 10 | 1.82 | 1.834 | 0.023 | 0.001 | — | — | — | — | 0.004 | 17.37 | — | -41.6 | -23.3 | -30.0 | -281.1 | |
400 | 1 | 1.49 | 1.077 | 0.041 | 0.001 | — | — | — | — | 0.004 | 10.40 | — | -40.8 | -23.8 | -29.9 | -270.8 | |
400 | 5 | 1.88 | 3.720 | 0.051 | 0.001 | — | — | — | — | 0.005 | 21.62 | — | -39.7 | -23.1 | -29.4 | -266.4 | |
400 | 7 | 2.07 | 4.773 | 0.036 | 0.001 | — | — | — | — | 0.005 | 22.72 | — | -38.8 | -22.6 | -29.3 | -259.5 | |
400 | 10 | 2.19 | 4.230 | 0.016 | 0.001 | — | — | — | — | 0.006 | 26.91 | — | -38.9 | -22.6 | -28.6 | -256.3 | |
450 | 1 | 2.31 | 9.312 | 0.114 | 0.003 | — | — | — | — | 0.006 | 23.08 | — | -36.2 | -18.2 | -28.9 | -249.6 | |
450 | 5 | 2.84 | 13.041 | 0.017 | 0.004 | — | — | — | — | 0.005 | 42.76 | — | -33.7 | -19.6 | -28.7 | -189.7 | |
450 | 7 | 3.08 | 14.128 | 0.034 | 0.009 | — | — | — | — | 0.009 | 53.22 | — | -33.3 | -19.4 | -28.3 | -171.4 |
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1.3 气体产物组分和同位素分析方法
2 结果与讨论
2.1 气体产率与组成特征
2.2 气体稳定碳同位素组成特征
2.3 水—矿物—有机质生气作用机制
3 结论
(1)单独含水体系下CH4产率从0.08 mL/gTOC升高至27.4 mL/gTOC,水—黄铁矿体系CH4产率从0.05 mL/gTOC升高至18.9 mL/gTOC,水—磁铁矿体系CH4产率从0.08 mL/gTOC升高至14.1 mL/gTOC。相较于单独含水体系分别降低了8.5 mL/gTOC和13.3 mL/gTOC。同时,矿物加入导致了重烃气体的明显下降,水—磁铁矿体系CO2产率低于单独含水体系表明了含铁矿物的加入抑制了水—有机质生气的过程。
(2)水—磁铁矿体系甲烷氢同位素(δD1)表现出低于单独含水体系,并且H2的产率明显的降低,表明磁铁矿的加入促进了早期H2的生成而与有机质之间发生了加氢作用。另外,CO2产率以及CO2碳同位素值低于单独有水体系,表明并未发生明显的氧化作用,不同的是水—黄铁矿体系CO2同位素略高于单独含水体系。
(3)在有水的热模拟实验中,水中H+的析出导致反应途径为碳正离子为主,水—黄铁矿和水—磁铁矿体系中异构烷烃比值(i-C4/n-C4)明显低于干酪根+水体系,这可能是由于含铁矿物的出现改变了水—干酪根反应的机制,抑制了碳正离子的生成。