东濮凹陷桥口-白庙地区天然气分布与成因探讨

Distribution and origin of natural gas in Qiaokou-Baimiao Area,Dongpu Depression

通过对桥口-白庙地区天然气地球化学及分布特征的分析研究,认为该区天然气主要有油型气、煤型气、混合气及深成气4种类型,各种类型的天然气分别具有不同的成因及成藏类型。桥口构造东翼深层天然气主要与葛岗集洼陷下第三系烃源岩有关,与煤系地层关系不大;白庙地区天然气与葛岗集洼陷及前梨园洼陷的烃源岩均有关,既有早期煤型气的充注,也有晚期油型气的充注,具有多源、多阶、多次充注复合成藏的特点。

Through studying the geochemical behavior and the distribution characteristics of natural gas in Qiaokou-Baimiao Area, four types of natural gas are proposed in the area, including oil-type gas, coal-type gas, mixed gas and plutonic gas. The natural gas has different origin types and accumulation types in Qiaokou-Baimiao Aeras. Based on the study, it is considered that the deep natural gas in the eastern flank of Qiaokou structure is related to the hydrocarbon source rock of Paleogene in Gegangji Sag, which has not much connection with coal measure strata. The natural gas is related to the hydrocarbon source rock of nol only Gegangji Sag but also Qianliyuan Sag. The hydrocarbon souree rocks have been filled with early coal-type gas and late oil-type gas. That is characterized by the features of compound accumulation with multiple sources, multiple stares and multple filling.