0 引言
1 样品与方法
1.1 实验样品
表1 煤和相邻页岩样品信息及基本地球化学参数Table 1 Information and basic geochemical parameters of coal and adjacent shale samples |
岩性 | 样品 编号 | 采样 地区 | 井号 | 采样 深度/m | 总有机碳 /%(wt) | 镜质组反射率 /% | 热解峰温 /℃ | 氢指数 /(mg/g) | 石英含量 /% | 黏土矿物 含量/% | 其他矿物含量/% | 镜质组 含量/% | 其他有机 组分/% |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
煤 | GXM-1 | 六盘水 | ZM1 | 801 | 50.42 | 1.05 | 456 | 122 | 9.0 | 6.0 | 10.0 | 55 | 20 |
GXM-7 | 六盘水 | ZM1 | 856 | 70.84 | 1.08 | 454 | 167 | 4.5 | 5.5 | 5.0 | 64 | 21 | |
GXM-10 | 六盘水 | NM1 | 637 | 42.00 | 2.00 | 526 | 22 | 9.0 | 7.0 | 10.0 | 55 | 19 | |
GXM-11 | 毕节 | BM1 | 610 | 63.00 | 2.20 | 524 | 31 | 5.0 | 10.0 | 10.0 | 53 | 22 | |
GXM-14 | 毕节 | AM1 | 668 | 23.13 | 2.41 | 498 | 32 | 8.0 | 20.0 | 15.0 | 50 | 7 | |
GXM-17 | 遵义 | FM1 | 644 | 62.01 | 4.31 | 605 | 5 | 5.0 | 15.0 | 5.0 | 60 | 15 | |
GXM-21 | 遵义 | FM1 | 669 | 65.67 | 4.42 | 609 | 7 | 8.0 | 5.0 | 8.0 | 65 | 14 | |
GXM-26 | 遵义 | JM1 | 927 | 76.94 | 3.07 | 605 | 5 | 5.0 | 5.0 | 5.0 | 80 | 5 | |
GXM-28 | 遵义 | JM1 | 944 | 87.94 | 3.26 | 605 | 5 | 2.0 | 2.0 | 4.0 | 85 | 7 | |
煤系 页岩 | GXM-2 | 六盘水 | ZM1 | 797 | 5.34 | 1.20 | 453 | 102 | 29.3 | 54.6 | 16.1 | — | — |
GXM-8 | 六盘水 | ZM1 | 857 | 13.49 | 1.66 | 464 | 100 | 12.8 | 79.7 | 9.5 | — | — | |
GXM-9 | 六盘水 | NM1 | 635 | 5.62 | 2.10 | 528 | 26 | 15.4 | 59.5 | 25.1 | — | — | |
GXM-12 | 毕节 | BM1 | 612 | 9.84 | 2.04 | 534 | 21 | 4.7 | 77.3 | 18.0 | — | — | |
GXM-15 | 毕节 | AM1 | 657 | 5.85 | 1.76 | 495 | 44 | 20.5 | 58.7 | 20.8 | — | — | |
GXM-16 | 遵义 | FM1 | 641 | 7.60 | 3.20 | 604 | 4 | 9.0 | 86.7 | 4.3 | — | — | |
GXM-20 | 遵义 | FM1 | 668 | 6.98 | 3.25 | 604 | 7 | 3.8 | 91.2 | 5.0 | — | — | |
GXM-27 | 遵义 | JM1 | 912 | 5.21 | 2.34 | 605 | 9 | 0.0 | 96.8 | 3.2 | — | — | |
GXM-29 | 遵义 | JM1 | 948 | 6.73 | 2.77 | 604 | 5 | 4.1 | 90.5 | 5.4 | — | — |
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1.2 基础地球化学参数测试
1.3 FE-SEM扫描电镜观察
1.4 低温液氮和CO2吸脱附实验
2 实验结果
2.1 煤和页岩基本地球化学特征
2.2 微观孔隙特征SEM观察
图2 煤和页岩储层SEM镜下微观孔隙特征(a)煤镜质组孔隙发育情况,少见明显的纳米孔隙(样品 GXM-7,深度为856 m);(b)页岩有机质孔隙发育情况(样品 GXM-8,深度为857 m);(c)页岩发育大的黏土矿物溶蚀纳米孔(样品GXM-8,深度为 857 m);(d)页岩普遍发育黏土矿物粒间或粒内纳米孔(样品GXM-16,深度为641 m);(e)页岩有机质与脆性矿物之间微裂缝(样品 GXM-8,深度为 857 m);(f)煤样脆性矿物内微裂缝以及有机质—矿物间微裂缝(样品 GXM-11,深度为610 m) Fig.2 Microscopic pore characteristics of coal and shale reservoirs under SEM |
2.3 低压吸脱附孔径表征
图3 典型煤和页岩氮气吸附—脱附曲线Fig.3 Typical nitrogen adsorption-desorption curves of coal and shale |
表2 煤和页岩样品低压氮气和二氧化碳吸附—脱附孔隙分布数据Table 2 Pore distribution of coal and shale samples by low-pressure nitrogen and carbon dioxide adsorption-desorption |
样品 编号 | N2吸附BET比表面/(m2/g) | N2吸附孔容/(cm3/g) | 微孔体积占比(<2 nm)/% | 介孔体积占比(2~50 nm)/% | 宏孔体积占比(> 50 nm)/% | 微孔(<2 nm)BET占比/% | 介孔(2~50 nm)BET占比/% | 宏孔(>50 nm)BET占比/% | 平均孔径(N2吸附)/nm | CO2吸附比表面积/(m2/g) | CO2吸附孔容/(cm3/g) | 平均孔径(CO2吸附)/nm |
---|---|---|---|---|---|---|---|---|---|---|---|---|
GXM-1 | 8.772 3 | 0.021 406 | 41.70 | 49.01 | 9.29 | 80.21 | 19.40 | 0.38 | 10.85 | 35.562 1 | 0.015 015 | 0.64 |
GXM-7 | 0.552 3 | 0.002 192 | 90.90 | 4.00 | 5.10 | 98.90 | 1.00 | 0.10 | 22 | 49.733 1 | 0.020 697 | 0.71 |
GXM-10 | 0.896 4 | 0.005 497 | 82.40 | 4.50 | 13.10 | 98.64 | 1.25 | 0.12 | 29.1 | 64.774 2 | 0.025 808 | 0.68 |
GXM-11 | 11.910 3 | 0.017 122 | 49.80 | 10.00 | 40.20 | 77.46 | 22.26 | 0.28 | 7.0 | 40.922 9 | 0.016 972 | 0.66 |
GXM-14 | 5.954 3 | 0.012 339 | 54.40 | 35.40 | 10.20 | 85.92 | 13.41 | 0.67 | 11.1 | 36.336 3 | 0.014 773 | 0.65 |
GXM-17 | 3.997 2 | 0.005 055 | 92.30 | 4.60 | 3.10 | 97.64 | 2.24 | 0.12 | 8.6 | 165.134 7 | 0.061 022 | 0.71 |
GXM-21 | 6.532 1 | 0.009 244 | 83.70 | 13.00 | 3.30 | 95.29 | 4.55 | 0.16 | 8.5 | 132.040 | 0.047 806 | 0.7 |
GXM-26 | 0.096 2 | 0.001 838 | 96.90 | 0.70 | 2.40 | 99.94 | 0.06 | 0.01 | 50.0 | 149.112 | 0.056 745 | 0.68 |
GXM-28 | 0.201 9 | 0.000 764 | 98.20 | 0.60 | 1.20 | 99.82 | 0.14 | 0.04 | 41.9 | 111.113 5 | 0.041 619 | 0.73 |
GXM-2 | 26.616 5 | 0.039 962 | 27.50 | 66.56 | 5.94 | 55.86 | 43.54 | 0.60 | 7.4 | 33.684 | 0.015 176 | 0.63 |
GXM-8 | 27.012 8 | 0.044 688 | 25.50 | 68.55 | 5.95 | 56.85 | 42.52 | 0.62 | 7.8 | 35.593 4 | 0.015 325 | 0.64 |
GXM-9 | 19.304 1 | 0.034 683 | 27.10 | 62.98 | 9.92 | 61.06 | 38.09 | 0.86 | 9.2 | 30.264 6 | 0.012 902 | 0.63 |
GXM-12 | 27.608 7 | 0.042 501 | 27.80 | 66.23 | 5.97 | 58.60 | 40.89 | 0.51 | 7.7 | 39.086 1 | 0.016 394 | 0.63 |
GXM-15 | 16.505 3 | 0.027 042 | 29.90 | 61.87 | 8.23 | 61.80 | 37.46 | 0.74 | 8.4 | 26.705 4 | 0.011 547 | 0.63 |
GXM-16 | 15.039 9 | 0.029 803 | 30.70 | 59.52 | 9.78 | 68.63 | 30.61 | 0.76 | 10.8 | 32.901 8 | 0.013 263 | 0.64 |
GXM-20 | 24.075 8 | 0.037 147 | 25.80 | 67.36 | 6.84 | 56.80 | 42.48 | 0.72 | 8.1 | 31.651 2 | 0.012 945 | 0.65 |
GXM-27 | 14.159 7 | 0.021 32 | 34.70 | 58.95 | 6.35 | 66.10 | 33.44 | 0.47 | 7.8 | 27.605 | 0.011 368 | 0.63 |
GXM-29 | 20.387 6 | 0.024 195 | 34.90 | 52.02 | 13.08 | 60.74 | 37.65 | 1.61 | 6.6 | 31.541 2 | 0.013 018 | 0.63 |
3 讨论
3.1 煤和页岩孔隙结构差异性对比
3.2 可抽提沥青对煤和页岩孔隙影响
图8 煤(a, c)和页岩(b, d)抽提前后氮气吸附—脱附曲线对比Fig.8 Comparison chart of nitrogen adsorption-desorption curves of coal (a, c) and shale (b, d) before and after extraction |