皖南巢县马家山地区油苗地球化学特征及油源

皖南巢县马家山地区油苗产出层位主要集中在下三叠统南陵湖组，为了查明其烃源岩，基于详细的野外剖面资料和采样记录，对该区古生界和中生界海相优质烃源岩层段进行系统研究和准确标定，在下二叠统栖霞组、上二叠统大隆组和下三叠统南陵湖组发现有机质相对富集的优质烃源岩小层。生物标志化合物指纹特征和绝对浓度定量分析表明，南陵湖组烃源岩样品的三环萜烷、四环萜烷、三萜类化合物、倍半萜烷及甾烷分布模式和组成特征与油苗样品相似，其藿烷、三环萜烷和甾烷绝对定量浓度也与油苗样品接近，而栖霞组和大隆组烃源岩样品与油苗样品具有明显差别。马家山地区油苗与南陵湖组烃源岩具有亲缘关系，是南陵湖组烃源岩的原生油气。图8表1参23

Geochemical characteristics of seepages and their source in Majiashan of Chaoxian, southern Anhui

Oil seepages of Majiashan in Chaoxian south of Anhui province mainly appear in the T1 n Formation. To determine their source rock, the Mesozoic and Paleozoic marine source rock in the area was studied and calibrated accurately based on the detail data of field profiles and sampling records. Source beds rich in organic matter have been discovered in the P1q, the Pz d and the T1 n. The fingerprint characteristics and absolute concentration of biomarkers indicate that the distribution and composition characteristics of tricyclic terpanes, tetracyclic terpanes, triterpanes, sesquiterpanes, and steranes of samples from T1 n are similar to those of the oil seepages. The absolute concentration of hopanes, tricyclic terpanes and steranes of oils from T1 n is also similar to the seepages. However, there are significant differences between the oil seepages and the samples from the P1q and Pzd. The Majiashan oil seepages have genetic relationship with the T1 n source rock and are the original oil of T1 n.