二次生烃过程中升温速率对生烃途径的影响 --以鄂尔多斯烃源岩生烃动力学研究为例

采用生烃动力学方法对鄂尔多斯已熟烃源岩进行模拟实验,与以往结果有所不同,实验证明在源岩二次生烃过程中,慢速升温并不利于液态烃的生成,而快速升温才更有利于生成液态烃。这可能是因为在慢速升温条件下,有机质可以有足够长时间缩聚成超大基团,而快速升温则易造成中等分子链的断裂,从而导致快速升温时抽提物产率高于慢速升温。因此,升温速率的差异对有机质的演化影响不只是影响反应速率,更重要的是会改变反应路径,从而对于像鄂尔多斯这样存在二次生烃的盆地,应适当重视那些高地温梯度区块石油资源的寻找。

EFFECTS OF HEATING RATE ON HYDROCARBON GENERATION PROCESS IN HYDROCARBON REGENER ATION :A CASE INVESTIGATION ON HYDROCARBON GENERATION KINETICS OF SOURCE ROCKS FROM THE ORDOS BASIN

Using hydrocarbon generation kinetics simulation experiment,chloroform extracts of source rocks from the Ordos Basin were investigated.Experimental results show that high heating rate is in favor of the formation of liquid hydrocarbon in hydrocarbon regeneration.The reason is that organic matters have enough time to polymerize and form super group in low heating rate,but break in high heating rate.Thus,heating rate has more influence on the reaction mechanism than reaction rate for organic matter evolution.So,for the Ordos Basin with two times of hydrocarbon generation,the field of high geotemperature gradient must be recognized in exploring for oil.