关键词: 四川盆地, 下古生界, 桐湾运动, 加里东运动, 油气勘探

Abstract: Early Paleozoic of Sichuan Basin underwent fi ve crustal movements, that is, Chengjiang movement, Tongwan movement, Yungui movement, Yeli movement, and Caledonian movement, caused by the northward subduction of Indian Plate and the eastward drift of Eurasian Plate. The two Plates collided with Qinghai-Tibet Plate, causing the latter to swift to the east and collapse in weak zone of Longmen mountain area of western Sichuan Basin. As a result, Qinghai-Tibet Plate reversed eastward and covered Yangtze platform plate, and Sichuan Basin was formed in succession. Because of the fi ve crustal movements, the big fault zones in Longmen Mountain got larger and larger in scale, as a result petroleum exploration reservoirs of Lower Paleozoic moved towards the east gradually and the exploration range got smaller. Exploration here proved that the Yaan-Longnvsi palaeohigh, the Luzhou palaeohigh, and the Tianjingshan palaeohigh were formed, which are favorable for petroleum exploration. In particular, the Yaan-Longnvsi palaeohigh is large, carbonate reservoirs here developed in each period, and there are also many local structures. Moreover, the northwest wing was eroded heavily and was leached by meteoric water for a long time. A great number of ancient karst fi ssures and caves emerged in all reservoirs. When they crossed each other vertically and horizontally, a giant fi ssure and cave system would be formed, which is very good for hydrocarbon accumulation and reservoir formation. There are also many local structures in Luzhou palaeohigh and Tianjingshan palaeohigh, and they could be used for Lower Paleozoic carbonate reservoir drilling and exploration.