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鄂尔多斯盆地中部大气田的部分气源来自于上覆晚古生代煤层,为评价晚古生代煤层作为气源岩的成烃贡献,以盆地晚古生代原煤样和显微单组分热模拟实验结果为基础,利用盆地内292组显微组分含量数据参与计算煤的生烃强度,估算出全盆地晚古生代煤成气原始生成量为(328.82～579.48)×1012m3,中间值为463.20×1012m3,其中边浅部中间值为61.49×1012m3,中深部为401.71×1012m3;在讨论该盆地晚古生代煤的成烃贡献时,重点论述了吸附于煤储层本身、未纳入常规天然气贡献之列的理论吸附气量。结果表明,鄂尔多斯盆地晚古生代煤源岩的排烃系数为82%～90%,煤对气体的吸附容纳能力非常有限,绝大部分煤成气在形成之后都运移到了围岩中。
Some gas sources in the large gas field in the central Ordos Basin came from the overlying Late Paleozoic coal seams. Based on the results of late Paleozoic coal samples and microscopic single component thermal modeling in the Late Paleozoic to evaluate the hydrocarbon generation contribution of the Late Paleozoic coal seam, Based on the 292 sets of micro-component data in the basin, the hydrocarbon generation intensity of coal was calculated. The initial Paleozoic coal-formed gas formation in the whole basin was (328.82 ~ 579.48) × 1012m3, and the median was 463.20 × 1012m3 The middle part of the coal is 61.49 × 1012m3 and the middle and deep part are 401.71 × 1012m3. In discussing the contribution of late Paleozoic coal to hydrocarbon generation in this basin, the theoretical adsorption capacity of adsorbed on the coal reservoir itself and not included in the contribution of conventional natural gas is emphatically discussed. The results show that the discharge coefficient of late Paleozoic coal source rocks in Ordos Basin is 82% -90%, and the adsorption capacity of coal to gas is very limited. Most coal-formed gas migrated into the surrounding rock after its formation.