Relationships of the iC4/nC4 and iC5/nC5 ratios with maturity of coal-derived gases of Triassic Xujiahe Formation in central Sichuan Basin, SW China
QIN Shengfei,HUANG Chunhu,ZHANG Benjian,YANG Yu,YUAN Miao
Table 1 Natural gas composition and carbon isotopic compositions of major gas fields in the Xujiahe Formation, Central Sichuan Basin.
Gas field Well name Member Main alkane gas composition/% Carbon isotopic composition/‰ Data source
CH4 C2H6 C3H8 iC4 nC4 iC5 nC5 iC4/nC4 iC5/nC5 C1+ C1/C1+ δ13C1 δ13C2 δ13C3 δ13C4
Guangan Guang19 T3x6 88.43 6.77 2.04 0.45 0.47 0.19 0.10 0.97 1.89 98.74 0.90
Guangan103 T3x6 87.40 7.59 2.10 0.40 0.37 0.14 0.07 1.07 2.03 98.22 0.89 [14]
Guangan109 T3x6 89.16 6.13 1.72 0.34 0.34 0.14 0.07 1.01 2.09 98.19 0.91 [14]
Guangan110 T3x6 89.81 6.08 1.65 0.33 0.32 0.13 0.07 1.02 1.97 98.71 0.91 [14]
Guangan115 T3x6 90.35 5.71 1.56 0.31 0.30 0.13 0.07 1.06 1.86 98.73 0.92
Guangan130 T3x6 66.63 6.36 1.82 0.37 0.39 0.16 0.09 0.96 1.75 76.35 0.87
Guangan133 T3x6 86.21 7.15 2.70 0.71 0.76 0.38 0.20 0.93 1.87 98.76 0.87 [14]
Guangan15 T3x6 86.47 7.29 2.81 0.55 0.61 0.20 0.15 0.90 1.33 98.43 0.88 -42.4 -27.8 -25.9 -25.6 [14]
Guangan7 T3x6 88.30 7.32 2.10 0.39 0.40 0.17 0.08 0.96 2.04 99.10 0.89 -42.5 -28.0 -24.2 -23.8 [22]
Guangan106 T3x4 93.43 4.09 0.71 0.13 0.09 0.04 0.01 1.41 2.79 98.65 0.95 -37.8 -25.7 -24.7 -22.1 [22]
Guangan107 T3x4 93.24 4.02 0.70 0.13 0.09 0.04 0.02 1.40 2.53 98.37 0.95
Guangan112 T3x4 92.71 4.52 0.86 0.15 0.12 0.05 0.02 1.26 2.38 98.62 0.94 [14]
Guangan113 T3x4 93.51 4.01 0.70 0.14 0.10 0.05 0.02 1.44 2.65 98.65 0.95 [14]
Guangan116 T3x4 93.07 4.60 0.77 0.16 0.10 0.05 0.02 1.64 2.72 98.93 0.94 [14]
Guangan12 T3x4 91.58 5.28 1.17 0.26 0.20 0.11 0.06 1.27 1.96 98.91 0.93
Guangan121 T3x4 92.49 4.67 0.83 0.18 0.12 0.06 0.03 1.45 2.32 98.45 0.94 [14]
Guangan123 T3x4 92.88 4.87 0.88 0.19 0.13 0.06 0.02 1.46 3.00 99.12 0.94
Guangan125 T3x4 92.11 4.73 0.90 0.21 0.13 0.07 0.02 1.63 2.96 98.26 0.94 [14]
Guangan127 T3x4 92.37 4.70 0.83 0.18 0.12 0.06 0.03 1.53 2.40 98.65 0.94
Guangan13 T3x4 86.07 4.98 0.99 0.21 0.14 0.07 0.03 1.48 2.50 92.63 0.93
Guangan131 T3x4 93.16 4.39 0.74 0.14 0.10 0.04 0.01 1.48 2.69 98.66 0.94 [14]
Guangan133 T3x4 92.30 4.20 0.68 0.13 0.09 0.05 0.02 1.44 2.08 97.98 0.94 [14]
Guangan144 T3x4 93.35 4.27 0.70 0.15 0.09 0.04 0.02 1.68 2.56 98.74 0.95 [14]
Guangan16 T3x4 92.32 4.94 1.05 0.24 0.18 0.07 0.03 1.35 2.67 98.89 0.93 [14]
Guangan3 T3x4 93.73 3.31 0.42 0.07 0.04 0.02 0.01 1.73 2.83 97.60 0.96 -37.7 -24.2 -22.1 -20.4 [22]
Guangan5 T3x4 93.96 3.84 0.64 0.12 0.08 0.04 0.02 1.51 2.40 98.86 0.95 -37.2 -25.0 -23.7 -22.2 [22]
Guangan122 T3x4 92.21 4.59 0.76 0.19 0.11 0.06 0.02 1.76 2.77 98.07 0.94 [14]
Guangan126 T3x4 93.32 4.43 0.75 0.15 0.10 0.05 0.02 1.49 2.42 98.90 0.94 [14]
Guangan128 T3x4 92.50 4.55 0.77 0.16 0.10 0.05 0.02 1.56 2.56 98.30 0.94 -37.7 -25.2 -23.3 -21.1 [23]
Guangan130 T3x4 92.37 4.94 0.96 0.16 0.11 0.03 0.01 1.47 2.70 98.62 0.94 [14]
Guangan143 T3x4 93.10 3.91 0.62 0.11 0.07 0.03 0.01 1.61 2.58 98.04 0.95 [14]
Anyue Yue101-8-X2 T3x2 87.69 7.99 1.97 0.42 0.37 0.17 0.09 1.14 1.89 99.02 0.89 -41.7 -26.9 -23.6 -24.1 [24]
Yue101-9-X1 T3x2 87.73 8.00 1.97 0.42 0.37 0.17 0.09 1.14 1.89 99.08 0.89 -42.7 -26.4 -23.1 -24.1 [24]
Yue101-X12 T3x2 87.60 7.82 2.13 0.49 0.44 0.18 0.10 1.11 1.80 99.08 0.88 -42.7 -26.9 -23.8 -24.5 [24]
Longgang Longgang17 T3x6 92.16 5.38 0.84 0.19 0.14 0.08 0.04 1.36 2.00 99.11 0.93 -38.7 -25.1 -23.6 -21.0 [24]
Longgang176 T3x6 91.32 5.88 1.19 0.21 0.18 0.06 0.03 1.17 2.00 99.15 0.92 -39.9 -24.7 -22.7 -21.5 [24]
He-
chuan		 Hechuan001-1 T3x2 89.93 5.53 1.27 0.33 0.24 0.13 0.06 1.42 2.39 97.75 0.92 -39.5 -27.1 -23.9 -24.4 [25]
Hechuan124 T3x2 89.19 6.57 1.68 0.44 0.33 0.21 0.09 1.33 2.33 98.51 0.91 -40.4 -27.4 -24.5 -25.3 [14]
Hechuan106 T3x2 89.27 6.75 1.73 0.40 0.31 0.17 0.07 1.29 2.43 98.70 0.90 -39.4 -26.9 -24.1 -24.6 [14]
Hechuan108 T3x2 89.80 6.42 1.43 0.34 0.27 0.16 0.07 1.26 2.29 98.49 0.91 -38.6 -27.1 -25.2 -26.3 [14]
Hechuan109 T3x2 93.09 4.04 0.75 0.23 0.15 0.11 0.05 1.56 2.29 98.76 0.94 -38.3 -26.2 -23.6 [25]
Hechuan125 T3x2 92.83 4.82 0.82 0.23 0.15 0.11 0.04 1.53 2.75 99.00 0.94 -37.2 -26.2 -24.5 -26.3 [14]
Hechuan001-18-X2 T3x2 89.92 6.67 1.57 0.29 0.25 0.12 0.05 1.16 2.40 98.87 0.91 -38.8 -27.3 -24.6 [14]
Hechuan001-2 T3x2 89.53 6.71 1.68 0.39 0.28 0.15 0.06 1.39 2.50 98.80 0.91 -39.3 -26.9 -23.9 -24.0 [14]
Hechuan1 T3x2 88.84 6.39 1.58 0.39 0.27 0.16 0.07 1.45 2.43 98.02 0.91 [14]
Hechuan103 T3x2 89.06 6.44 1.53 0.39 0.32 0.20 0.09 1.23 2.15 98.60 0.90 -39.3 -27.1 -24.2
Long-
nüsi		 Nü112 T3x4 86.01 7.41 2.26 0.55 0.49 0.27 0.14 1.12 1.91 97.81 0.88
Nüshen2 T3x4 87.13 6.57 1.53 0.33 0.26 0.14 0.06 1.26 2.21 98.41 0.89
Moxi Mo17 T3x2 87.94 6.22 1.99 0.63 0.52 0.31 0.15 1.21 2.08 98.01 0.90
Mo73 T3x2 89.45 6.16 1.74 0.43 0.33 0.13 0.06 1.32 2.29 98.40 0.91
Mo85 T3x2 88.88 6.49 1.94 0.58 0.45 0.25 0.10 1.28 2.55 98.82 0.90
Mo202 T3x4 86.44 7.63 2.70 0.55 0.56 0.23 0.12 0.99 1.88 98.55 0.88
Mo48 T3x4 86.65 7.26 2.48 0.47 0.50 0.20 0.11 0.94 1.77 97.95 0.88
Mo64 T3x4 87.14 7.20 2.41 0.47 0.46 0.18 0.09 1.02 1.99 98.20 0.89
Gas field Well name Member Main alkane gas composition/% Carbon isotopic composition/‰ Data source
CH4 C2H6 C3H8 iC4 nC4 iC5 nC5 iC4/nC4 iC5/nC5 C1+ C1/C1+ δ13C1 δ13C2 δ13C3 δ13C4
Nan-
chong		 Xi20 T3x4 88.40 6.20 2.26 0.48 0.52 0.21 0.13 0.92 1.64 98.70 0.90 -41.4 -28.3 -25.3 -24.4 [14]
Xi005-X1 T3x4 86.70 6.55 2.64 0.51 0.63 0.23 0.15 0.80 1.58 98.05 0.88
Xi051-X2 T3x4 86.98 6.77 2.80 0.56 0.71 0.27 0.17 0.79 1.55 98.75 0.88
Xi13-1 T3x4 85.00 6.64 2.74 0.52 0.65 0.26 0.17 0.79 1.56 96.66 0.88
Xi32 T3x4 82.72 7.20 3.30 0.63 0.84 0.31 0.21 0.76 1.48 95.76 0.86
Xi48 T3x4 88.18 6.07 2.09 0.42 0.47 0.18 0.11 0.89 1.62 97.73 0.90
Xi56 T3x4 88.00 6.22 2.32 0.48 0.53 0.20 0.12 0.89 1.66 98.20 0.90
Xi57 T3x4 86.89 6.77 2.77 0.52 0.66 0.23 0.15 0.79 1.51 98.52 0.88
Xi58 T3x4 85.62 7.08 2.84 0.52 0.60 0.19 0.13 0.86 1.54 97.61 0.88
Xi62 T3x4 82.33 7.58 3.57 0.74 1.12 0.49 0.38 0.66 1.31 97.45 0.84
Xi64 T3x4 88.92 6.03 2.16 0.44 0.48 0.20 0.13 0.91 1.58 98.88 0.90
Xi65 T3x4 87.71 6.22 2.32 0.44 0.54 0.21 0.14 0.81 1.54 98.08 0.89
Xi71 T3x4 88.66 5.99 2.00 0.42 0.47 0.18 0.12 0.90 1.59 98.29 0.90
Xi72 T3x4 87.31 6.68 2.83 0.57 0.72 0.30 0.19 0.79 1.56 99.50 0.88
Tong-
nan		 Tongnan101 T3x2 87.27 7.26 2.74 0.53 0.53 0.23 0.11 1.00 2.09 98.67 0.88 -41.5 -28.2 -25.0 -26.1 [14]
Tongnan111 T3x2 87.95 7.12 2.48 0.53 0.48 0.23 0.10 1.10 2.30 98.89 0.89 -41.1 -27.9 -24.7 -25.6 [14]
Tongnan104 T3x2 87.88 7.14 2.52 0.56 0.50 0.22 0.10 1.12 2.20 98.92 0.89 -40.9 -27.9 -24.6 -25.7 [14]
Tongnan001-2 T3x2 88.74 6.78 2.12 0.51 0.43 0.23 0.10 1.19 2.30 98.91 0.90 -40.5 -27.4 -24.4 -25.6 [14]
Tongnan105 T3x2 89.57 6.49 1.85 0.43 0.35 0.19 0.08 1.23 2.38 98.96 0.91 -40.3 -27.5 -24.5 -25.0 [14]