松辽盆地昌德气田天然气成因及成藏模式

通过对昌德气田中天然气的化学组分和碳同位素的分析发现 ,该区天然气的成因类型很复杂 ,既有有机成因天然气 ,又有无机成因天然气。昌德气藏和昌德东气藏中的天然气成因有一定的差别。昌德气藏中天然气重烃含量相对较低 ,出现重碳同位素和负碳同位素系列 ,可能有无机烃类气体的混入。昌德东气藏除有机成因的煤型气外 ,还发现有幔源成因的高纯二氧化碳气藏。非烃气体在纵向上的分布以登娄库组以下地层的营城组火山岩系地层含量最高。在平面上高含量非烃气体的分布常与深大断裂的走向一致 ,主要为无机成因

ORIGIN AND ACCUMULATION MODEL OF NATURAL GASES IN CHANGDE GAS FIELD,THE SONGLIAO BASIN

Based on analysing the chemical composition and carbon isotopes of natural gases,mult genetic gases have been founded in Changde gas field,such as organic gases and inorganic gases.Heavy carbon isotopes and negative carbon isotopic series indicate that Changde gas accumulation had been mixed with inorganic hydrocarbon gases,whereas normal chemical composition and carbon isotopes of natural gases indicate that Changdedong gas pool is main organic origin gas,mostly coal formed gases,but the discoveries of mantle source gases give a new clue for exploration in this area.The distribution of high content inorganic gases is often associated with deep faults.