Accumulation conditions and exploration directions of Ordovician lower assemblage natural gas, Ordos Basin, NW China

XU Wanglin,LI Jianzhong,LIU Xinshe,LI Ningxi,ZHANG Caili,ZHANG Yueqiao,FU Ling,BAI Ying,HUANG Zhengliang,GAO Jianrong,SUN Yuanshi,SONG Wei

Fig. 5. Cores and inclusions. (a) At 3602.41 m in Ma 4 Member of Well TA112, the dissolution cavities are filled with the calcite and yellow sulfur crystals; (b) At 3626.17 m in Ma 4 Member of Well TA112, gas-liquid inclusions, Raman spectroscopy indicates the H2S content of 85.7% and the CH4 content of 14.3%, and the liquid phase is dominated by water; (c) At 4064.6 m in Ma 3 Member of Well SH473, gas hydrocarbon inclusions in the dolomite; (d) At 4 064.6 m in Ma 3 Member of Well SH473, the Raman spectrum surface scan of the gas-liquid hydrocarbon-bearing inclusions in the pink box of Figure 5c, the relative intensity of the Raman scan in the color scale ranges from 0 to 1654, the Raman peak position is 2914.45 cm-1, the gas phase is pure methane, and the gas-liquid ratio is 90%.