两种裂解气中轻烃组成差异性及其应用

LIGHT HYDROCARBON COMPOSITION DIFFERENCE BETWEEN TWO KINDS OF CRACKED GASES AND ITS APPLICATION

为了寻找干酪根和原油裂解气识别指标,对两种裂解气中轻烃各化合物开展了深入的对比研究。热模拟实验表明干酪根裂解气和原油裂解气轻烃组成存在差异,在C7轻烃组成中,原油裂解气中甲基环己烷/正庚烷和(2-甲基己烷+3-甲基己烷)/正己烷均明显高于干酪根裂解气;通过对海相典型原油裂解气和干酪根裂解气的轻烃组成对比研究进一步证实了两种裂解气在轻烃组成上存在差异,原油裂解气中甲基环己烷/正庚烷一般大于1.0,(2-甲基己烷+3-甲基己烷)/正己烷一般大于0.5,而干酪根裂解气则反之。塔里木盆地满东-英吉苏地区天然气轻烃组成具有环烷烃和异构烷烃含量高的分布特征,应用上述指标对该区天然气成气过程进行判识,结果表明满东-英吉苏地区天然气主要为原油裂解气。

In order to look for the criteria of identifying the gases crucked from kerogens and crude oil respectively, the light hydrocarbon compounds in the two cracked gases were studied and contrasted thoroughly. By means of thermal simulation experiments, it was indicated that there exists difference between kerogen-cracked gas and crude oil-cracked gas; and, in light hydrocarbon C, composition, the methylcyclohexane-to-n-heptane ratio and (2-methyl hexane +3-methyl hexane) -to-n-hexane ratio of crude oil-cracked gas are much higher than those of kerogen-cracked gas. Through investigating and contrasting the light hydrocarbon composition of typical marine crude oil-cracked gas with that of kerogen-cracked gas, it was further proved that there exists difference between the two cracked gases; and, in crude oil-cracked gas, the methyl-cyclohexane-to-n-heptane ratio is more than 1.0 and the (2-methyl hexane+3-methyl hexane)-to-n-hexane ratio more than 0. 5 in general, however, the kerogen-cracked gas is quite the contrary. The light hydrocarbon composition of the natural gas in Mandong-Yingjisu region in Talimu Basin is of the characteristic of high naphthenic hydrocarbon and isoalkane contents. According to the identified results of the origin of the natural gas in the region in light of the criteria mentioned above, it was considered that the natural gas in the region mainly belongs in the crude oil-cracked gas.