准噶尔盆地南缘中二叠统烃源岩封闭体系生烃热模拟实验分析

通过对准噶尔盆地妖魔山与大龙口剖面的2个烃源岩样品进行封闭体系模拟实验分析,获取不同温度条件下中二叠统烃源岩生油气量及相关地球化学参数,研究该地区Ⅰ型干酪根与Ⅱ1型干酪根的生烃演化模式,另外,选取该地区的相关地球化学参数与烃源岩厚度,计算准南缘中二叠统烃源岩至现今的天然气不同组分强度。结果表明：二叠系烃源岩Ⅰ型干酪根生油气量明显高于Ⅱ1型干酪根,生油能力持续时间长,生油区间的RO值为0.6%-2.0%;Ⅱ1型干酪根生油能力明显较弱,生油区间RO值为0.7%-1.3%。Ⅰ型干酪根生气的RO值从1.3%开始,生气量逐渐增加,Ⅱ1型干酪根生气要早一些,从RO值为1.0%时开始,生气量也明显低于Ⅰ型。3个剖面以大龙口地区二叠系烃源岩的生气强度最高,为167.52×108m^3/km^2,甲烷与乙烷的强度也最高;其次为妖魔山剖面,生气强度为118.88×108m^3/km^2;红雁池剖面的生气强度最低,为11.46×108m^3/km^2。总体而言,准噶尔盆地南缘生气潜力较高,勘探前景广阔。

Productions of Closed System Experiments for Middle Permian Source Rock in Southern Junggar Basin

After two source rocks samples in the Yaomoshan and Dalongkou sections in Junggar basin are subjected to closed system experiment,we get the amounts of hydrocarbon generation and the geochemical parameters and set up a mode of hydrocarbon generation for the kerogenⅠand Ⅱ1 source rocks at different temperature conditions.The intensity of the different gas constitutes generated from the middle Permian source rock in southern Junggar basin is computed by choosing the related geochemical parameters and the thickness of the mudstone.The results indicate that the amount of oil and gas generation from the typeⅠkerogen is more than that of type Ⅱ1 kerogen.The duration of oil generation of the typeⅠkerogen is from 0.6% to 2.0% RO,in contrast that the thermal maturity for the type Ⅱ1 kerogen is in range of 0.7%-1.3%.The type kerogen begins to generate the gas at RO of 1.3%,and the amounts of gas production go up with thermal maturity increase;the type Ⅱ1 kerogen onset the gas generation at RO of 1.0%.Although the time of gas generation is earlier than that of the type Ⅰ kerogen,the gas production in volume is less than that of the type Ⅰ kerogen.In three geological sections,the gas generation intensity in the Dalongkou section is largest,about 167.52×108 m3/km2,with the largest intensity of methane and ethane,the Yaomoshan section is second,about 118.88×108 m3/km2,and the last is the Hongyanchi section,about 11.46×108m3/km2.So,the gas generation potential in the Southern Junggar basin is great with extensive exploration.