DISTRIBUTION CHARACTERISTICS AND CONTROL FACTORS OF HYDROGEN SULFIDE IN XISHAN COAL MINE OF SOUTHERN MARGIN OF JUNGGAR BASIN IN CHINA

Resumen

The regional structure of Xishan coal mine, located in the binding site of southern margin of Junggar basin and northern mountain Tianshan, belongs to the foothill fault-fold structural belt of southern margin of Junggar Basin. Most the coal seams which were formed by continental facies are in the range of medium-extra low sulfur and part of the coal seams belong to high sulfur coal. The hydrogen sulfide in coal seam concentrate anomaly and distribute very unevenly, with the maximum value of H₂S up to 2.11%. The gas composition in coal bed mainly are N₂ and CH₄, components H₂S, CO₂, C₂H₆, C₃H₈ and another heavy hydrocarbon. The mirror reflectance of coal is generally between 0.5% to 0.7%. The abundant source rocks are the strong material basis for the formation of H₂S. The pore structure of coalbed belongs to the fracture-pore type. The medium and better reservoir have a wide range of distribution. The proportion of roof microclastic rocks and floor microclastic rocks of coal seam is up to 75% and 87% respectively. These factors are conducive to the enrichment of H₂S. The thick aquifer formed in the sag basement, under the control of hydrodynamic block gas, provides a huge space of occurrence and migration for groundwater and H₂S. Along the runoff direction, the salinity, pH value and H₂S content in regional groundwater gradually increase. The water is rich of sulfate ion, reflecting a closed well of regional deep confined water. In sufficient organic matter and reducing environment, the hydrogen sulfide will come into being in the role of BSR or TSR.