中文摘要：

在共和盆地万秀寺剖面下白垩统50．40m厚的钙质泥岩和233．03m厚的粉砂岩中，发现了良好的油气显示，从中采集46块含油钙质泥岩和粉砂岩样品，进行热解、沥青“A”族组成、饱和烃气相色谱、饱和烃色谱一质谱和同位素分析，并进行油源对比研究。结果表明：共和盆地下白垩统钙质泥岩中的油气是生成的油气没有排出并以吸附或游离状态的形式滞留其中所致；粉砂岩中的油气与下白垩统黑色泥岩和钙质泥岩具有亲缘关系，是烃源岩所生成油气就近运移并聚集的结果：无论是钙质泥岩中的烃类还是粉砂岩中的油气均具有成熟原油的特征：共和盆地下白垩统粉砂岩和钙质泥岩的含油气丰度较高，含油气总量分别为0．42和1．44kg·t^-1．具有良好的页岩油气勘探远景。

英文摘要：

Hydrocarbon seeps were discovered in 50.40 m thick calcareous mudstones and 233.03 m thick sihstones of the Lower Cretaceous in Wanxiusi outcrop, Gonghe Basin. forty-six calcareous mudstone and sihstone samples were collected and the tests including pyrolysis, the group composition of chloroform asphalt ＂ A＂ , the gas chromatogram of saturated hydrocar- bon, the gas chromatography-mass spectrormetry of saturated hydrocarbon and isotope were carried out, and oil-source correla- tion was researched. The results show that the hydrocarbons in the form of absorption and free state in the calcareous mud- stones of the Lower Cretaceous are generated and retained in the calcareous mudstones. And the hydrocarbons in the silt- stones are related to the black mudstones and the calcareous mudstones of the Lower Cretaceous. The hydrocarbons generated by the source rocks migrate into the sihstones and accumulate nearby. The hydrocarbons both in the calcareous mudstones and in the siltstones are mature oil. Gonghe Basin is rich in oil and gas resources in the Lower Cretaceous with total hydrocar- bon content of 0.42 kg . t^-1 in sihstone and total hydrocarbon content of 1.44 kg . t^-1 in calcareous mudstone, which shows a great exploration potential of shale gas and oil in the basin.