Mechanisms of carbon isotopic fractionation in the process of natural gas generation: Geochemical evidence from thermal simulation experiment

PENG Weilong,LIU Quanyou,HU Guoyi,LYU Yue,ZHU Dongya,MENG Qingqiang,GUO Fengtao,WANG Ruoli

Table 1 Yield of gas products of low mature coal sample from the Lower Permian Shanxi Formation in eastern Ordos Basin.

Heating mode Temperature/ oC Gas component yield/(mL?g-1) Alkane gas yield/ (mL?g-1) Heavy hydrocarbon gas yield/(mL?g-1) CH4 C2H6 C3H8 iC4H10 nC4H10 iC5H12 nC5H12 H2 CO2 H2S Rapid heating 320 0.21 3.37 0.21 340 0.62 0.02 3.68 0.64 0.02 360 1.04 0.08 0.02 4.95 1.13 0.09 380 2.29 0.42 0.11 0.02 0.02 0.01 15.88 0.03 2.87 0.58 400 4.52 0.99 0.17 0.01 0.01 14.93 5.70 1.18 420 11.02 3.34 0.75 0.04 0.06 26.41 15.20 4.18 440 22.53 6.41 1.58 0.09 0.14 0.01 0.01 30.31 30.78 8.25 460 36.31 8.48 1.94 0.13 0.16 0.02 0.01 28.30 47.04 10.73 480 50.80 9.70 1.99 0.10 0.14 0.62 34.86 62.73 11.93 500 64.36 10.27 1.60 0.07 0.07 1.06 41.15 76.38 12.02 525 93.92 9.38 0.69 0.02 0 40.87 104.01 10.09 550 135.4 6.49 0.33 0.06 0.10 0.04 0.04 1.50 51.01 142.44 7.04 575 167.14 2.27 1.83 54.51 169.40 2.27 600 194.15 1.08 2.10 49.31 195.24 1.08 625 229.41 0.75 0 2.59 48.27 230.16 0.75 Slow heating 320 0.45 0.04 0.01 6.22 0.50 0.05 340 1.22 0.15 0.02 9.65 1.40 0.18 360 3.93 0.93 0.17 0.01 0.01 16.31 5.05 1.11 380 8.27 2.47 0.56 0.03 0.06 0.01 25.28 11.39 3.13 400 20.89 5.41 1.14 0.05 0.10 0.01 0.01 28.11 27.61 6.71 420 31.76 7.15 1.55 0.08 0.14 0.01 0.01 34.28 40.70 8.94 440 44.67 7.72 1.35 0.08 0.09 0.42 36.69 53.91 9.24 460 69.41 8.62 1.01 0.06 0.04 0.54 42.48 79.15 9.73 480 89.91 6.98 0.38 0.02 1.36 43.69 97.28 7.37 500 118.7 4.58 0.07 1.13 46.80 123.34 4.65 525 150.6 1.86 0.02 1.39 37.17 152.48 1.88 550 199.4 0.78 0.05 2.38 40.24 200.22 0.82 575 236.3 0.77 3.75 35.21 0.34 237.07 0.77 600 287.12 0.76 5.64 34.12 0.47 287.89 0.76 625 302.26 0.48 6.81 29.05 302.74 0.48