中文摘要：

根据天然气组分、碳同位素组成以及伴生凝析油的轻烃参数等资料并结合地质背景,确定了天然气的成因类型,并分析其成熟度与来源。研究表明,辽东湾地区已发现的天然气以湿气为主,根据乙烷碳同位素组成可划分为油型气和偏腐殖型气2种成因类型,分别对应于Ⅱ1型和Ⅱ2型有机质。油型气主要分布在JZ21-1、JZ25-1和JZ25-1S油气田,偏腐殖型气主要分布在JZ20-2油气田;油型气主要源于有机质热成熟度0.6%～1.1%的烃源岩,偏腐殖型气主要源于有机质成熟度1.1%～1.3%的烃源岩;辽东湾地区有机质热成熟度大于0.6%的烃源岩均可作为有效气源岩。

英文摘要：

In combination with geological background,the genetic types and origin of the found gases in the Liaodong Bay,Bohai Bay basin was studied based on the analysis data about their components,carbon isotope and light hydrocarbon.The results showed that the found gas in Liaodong Bay is mainly wet gas,and could be classified into two genetic types,which are petroliferous gas and humic-prone gas,based on δ13C2.The two genetic types are correspond to organic materials of type Ⅱ1 and type Ⅱ2.The petroliferous gas distributes in hydrocarbon fields of JZ21-1、JZ25-1 and JZ25-1S.And the humic-prone gas distributes in JZ20-2 hydrocarbon field.The petroliferous gas mainly comes from the source rocks with 0.6%~1.1%（Ro）,and for the humic-prone gas comes from the ones with 1.1%~1.3%（Ro）.It is concluded that the source rocks with bigger than 0.6%（Ro） in Liaodong Bay area could serve as effective gas source rocks,which suggests an optimistic prospect for gas exploration.