【摘要】 辽河坳陷东部凹陷是辽河油田重要的天然气生产区,随着勘探程度的不断深入,亟待从整体格局上对天然气成因、成藏与分布规律进行系统研究,确定下一步勘探方向与勘探潜力。为此,依据该区天然气的地球化学特征(含氮特征、干燥系数、碳同位素特征、甲烷氢同位素特征、轻烃特征等),对其成因类型和分布规律进行了分析。结果认为:该区天然气具有较明显的混源特征,既表现为不同热演化程度天然气的混合,也表现为不同成因类型天然气的混合;不同层系、不同地区天然气混合比例有着较大区别,总体上以生物—油型混合气和油型—煤型混合气为主;按照成熟阶段来划分则以热解气为主,裂解气和过渡带气各占3%和6%。更多还原

【Abstract】 The eastern sag of the Liaohe Depression is one of the major gas production zones in the Liaohe Oilfield.Along with the deepening degree of exploration,it is urgent to systematically study the genesis,accumulation and distribution of gas,so as to evaluate gas potentials and identify future exploration targets.The genetic types and distribution patterns of gas are defined through analyzing the geochemical features of gas,such as nitrogen content,dry coefficient,carbon isotopic characteristics,hydrogen isotopic characteristics of methane,and light hydrocarbon features.The natural gases in the study area are obviously of mixed origins.There are both source-mixed gases of different thermal evolution stages and mixed gases of different genetic types.The composition of mixed gases varies greatly in different layers and in different areas.Biogenetic-terrigenous-dominated petroliferous mixed gas and terrigenous-dominated coal-related mixed gases are predominant as a whole.As to maturation stages,gas from thermal degradation is predominant,while pyrolysis gas and transition gas are much less,accounting for 3% and 6% respectively.更多还原