中扬子地区志留系“满坳含烃”特征与油气勘探目标

Hydrocarbon-bearing Characteristics in Whole Depression and Exploration Activity Target for Silurian Succession in Middle Yangtze Area

志留系在中扬子地区广泛分布,多期海平面升降形成的海进体系域和高位体系域控制砂泥岩纵横向展布,为各类地层岩性圈闭创造了有利的条件,具有"满坳含烃"的地质特征。多期油气充注、运移和聚集形成志留系普遍含烃,但丰度不均衡。所以,要突破构造控烃的局限性,把扬子地区的鄂西渝东区和江汉平原区作为今后志留系勘探的主要目标。

Silurian successions are distributed widely in the Middle Yangtze Area, the vertical and horizontal distribution of Silurian sandstones and mudstones in the area is controlled by the transgressive systems tract and highstand systems tract formed as a result of multiphase sea level fluctuation, which creates the favorable condition for forming various stratigraphic traps, with hydrocarbon--bearing characteristics in whole depression. The multiphase hydrocarbon filling, migration and accumulation resulted in general hydrocarbon--bearing characteristics in Silurian, with unequal petroliferous abundance. Therefore, the authors hold that the limitation on hydrocarbon distribution controlled by structure should be broken down, the western portion of Hubei Province and eastern portion of Sichuan Province in Yangtze Area should be taken as a main oil ＆ gas exploration target in Silurian in the days to come.