内蒙古西部额济纳旗及邻区地表油气化探烃类异常的特征

摘要

Based on the geological condition analysis of surface geochemical prospecting for oil and gas in Ejin Banner and its vicinities, the authors systematically analyzed such indexes as concentrations of methane and heavy hydrocarbon, dry coefficients and methane carbon isotope.There exist high hydrocarbon background values and strong hydrocarbon anomalies in the area, and the anomalies are characterized by relatively heavy methane carbon isotope and high dry coefficient.Combined with an analysis of typical oil and gas reservoirs and geochemical exploration anomalies in different geological backgrounds, it is considered that there are two sets of petroleum systems with different evolution degrees of hydrocarbon source rocks, and that the oil and gas geochemical exploration anomalies are mainly hydrocarbon geochemical anomalies of highly mature-overmature hydrocarbon source rocks or mixed-source oil and gas reservoirs (or compound oil and gas reservoirs).%在对额济纳旗及其邻区地表油气化探地质条件分析的基础上,系统分析了地表油气化探剖面酸解烃甲烷与重烃含量、干燥系数、甲烷C同位素等指标的分布特征,区内具有高的烃类背景值和强的烃类异常显示,并具有甲烷C同位素偏重、干燥系数大的特点.结合典型油气藏和不同地质背景的化探异常分析,认为区内存在烃源岩演化程度不同的2套舍油气系统,以与高成熟-过成熟烃源岩有关的烃类化探异常显示或混源油气藏(或复合油气藏)的烃类化探异常显示为主.