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本文应用磷灰石裂变径迹法研究淮南煤田的构造热演化特征 ,探讨其煤层气资源潜力。结果表明 :研究区自晚古生代以来 ,至少发生过三次明显的构造热事件 ,分别在 2 40 ,1 40和 80Ma左右 ;古地温梯度比现地温梯度低 ,估计本区整个剥蚀厚度大于 2 0 0 0m。从该区的构造热演化特征可以得出以下初步结论 :该区煤化作用主要发生在 2 40～ 1 40Ma之间 ,即中生代以来的第一、二次构造热事件使晚古生代煤逐渐变质为气煤级 ,少部分达肥煤级。煤层气生气量不是太高 ,白垩纪晚期的构造热运动导致热成因煤层气逸失 ,构造发育的地区逸失较多 ,煤层气资源潜力可能不大 ;构造不发育的地区逸失较少 ,可能是煤层气开发较为有利的地区。
In this paper, we use apatite fission track method to study the tectonic thermal evolution characteristics of Huainan coalfield and explore the potential of CBM resources. The results show that at least three obvious tectono-thermal events occurred since the Late Paleozoic in the study area, at about 240, 140 and 80 Ma, respectively. The paleogeothermal gradient is lower than the current geothermal gradient, and the total erosion thickness in this area is estimated to be greater than 200 0m. Based on the tectonic thermal evolution of the area, the following preliminary conclusions can be drawn: The coal-formation in this area mainly occurs between 240 and 140 Ma, that is, the first and second tectonic thermal events since the Mesozoic have made Late Paleozoic coal gradually metamorphic to gas Coal grade, a small part of fertilizer and coal grade. CBM gas generation is not too high. The tectonic thermal movement in the late Cretaceous resulted in the loss of thermal genetic coalbed methane, with more unconsolidated areas in the tectonic development and less potential for CBM resources. Gas development more favorable areas.