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为探讨煤岩中煤层气的热演化特征,选取柴达木盆地侏罗系未成熟煤岩样品进行加水热模拟实验,分析了煤岩气、液态产物及固体有机质的热演化特征。实验结果表明,气态烃可以形成于煤岩热演化的各个阶段,液态烃主要在生油窗范围内生成且生成量相对低。生油高峰时烃类气体中甲烷产率较低,之后迅速增加;重烃气体在大量生油阶段和高成熟阶段早期产率相对较高,之后开始降低。非烃类气体中二氧化碳的体积分数明显高于氮气的体积分数,均主要形成于生油阶段;氢气的体积分数普遍较高,随温度升高先降低后增高,最小值出现于生油高峰之后。煤岩能够生成气态烃和液态烃,总体具有较高的甲烷产率,远高于一般煤层实测的含气量,具备形成煤层气的物质基础。
In order to explore the characteristics of thermal evolution of coalbed methane in coal and rock, the Jurassic immature coal and rock samples from the Qaidam Basin were selected for hydrothermal simulation experiments. The thermal evolution characteristics of coal-rock gas, liquid products and solid organic matter were analyzed. The experimental results show that the gaseous hydrocarbons can be formed in all stages of the thermal evolution of coal and rock, and the liquid hydrocarbons are mainly generated in the oil production window with a relatively low production. At the peak of oil production, the yield of methane in hydrocarbon gas is low and then increases rapidly. The heavy hydrocarbon gas has a relatively high yield in the period of large oil production and early maturity, and then begins to decrease. The volume fraction of carbon dioxide in non-hydrocarbon gases was significantly higher than the volume fraction of nitrogen, which were mainly formed in the oil-producing stage. The volume fraction of hydrogen was generally high, then decreased with the increase of temperature, then increased with the increase of the minimum, . Coal and rock can generate gaseous hydrocarbons and liquid hydrocarbons, generally have a higher methane yield, much higher than the measured gas content of the general coal seam, with the material basis for the formation of CBM.