松辽盆地莺山断陷深层天然气地球化学特征与各套烃源岩定量贡献

根据莺山断陷深层天然气组成及轻烃指纹、组分碳同位素、烃源岩等地球化学分析资料，对天然气和烃源岩评价认为，营城组和沙河子组天然气主要是腐殖型和腐泥型的混合成因气，具有高—过成熟演化特征；沙河子组为好—中等烃源岩，营城组为中等—好烃源岩，有机质类型以Ⅲ型为主、Ⅰ型和Ⅱ型为辅；侏罗系为好烃源岩或非_差烃源岩，有机质类型为Ⅲ型，处于过成熟演化阶段。根据莺山断陷深层天然气和烃源岩空间分布及地球化学特征，选择营城组、沙河子组、侏罗系丰度高的烃源岩样品，利用烃源岩吸附气轻烃指纹分析及特征参数表征深层各套烃源岩，通过化学模型和智能神经网络数学模拟方法建立烃源岩贡献模板，测试了深层3套烃源岩对每口井天然气的定量贡献，沙河子组烃源岩贡献大于50%，首次认识了莺山断陷深层天然气的定量来源及各套烃源岩的贡献。

Geochemical characteristics of natural gas and the contribution ratio of source rocksin the Yingshan Fault Depression of the Songliao Basin

Based on the character of gas composition and isotope and light hydrocarbon fingerprint and source rock in Yingshan Fault Depression,gases in the Yingcheng Formation and Shahezi Formation are derived from a mixture of humic and sapropellic source rocks,and are at high-mature to over-mature thermal evolution stage.Shahezi Formation is a set of good-medium source rocks,and Yingcheng Formation is a set of medium-good source rocks.The organic matter is dominated by type Ⅲ kerogen and followed by type Ⅰ and type Ⅱ.Jurassic is a set of good or non-poor source rocks,and the organic matter is type Ⅲ.It is at over-mature evolution stage.According to the gas geochemistry characteristic and source rock distribution feature in Yingshan Fault Depression,selecting source rock specimens in Yingcheng Formation ,Shahezi Formation and Hushiling Formation and according to the hydrocarbon fingerprint characteristic parameter of hydrocarbon source rocks,the calculating model uses mathematical simulation method to test the ration contribution and adjust per mouth of well of natural gas from three suits of hydrocarbon source rocks to analog computation.Results show,contribution of the Shahezi Formation source rock is more than 50%.It is the first time to obtain natural gas ration source from and ration contribution of hydrocarbon source rocks in Yingshan Fault Depression.