DISCUSSION ON THE MECHANISM OF FORMING JURASSIC SECONDARY GAS RESERVOIR IN THE SOUTH PART OF WEST SICHUAN
Sun Fu-nan (The Institnte in Northwest Sichusn Cas Field of Sichuan Petroleum Administration), Zen Qing-yong
The south part of West Sichuan. i.e. the southwest port of West Sichuan depression in Sichuan Basin,is about 1. 3x104km2. In such as oxidized environment, the organic carbon content of Jurassic in the area is quite low. without the capability of generating oil or gas. But the gas show is widespread and commercial gas flow is obtained while drilling. It has a certian production capacity and reserve. The authors consider that Jurassic in this area belongs to secondary gas reservoir after studying.The reasons why the secondary gas reservoir can be formed arc that ① the Upper Triassic under Jurassic has abundent oil gas resources; ② structural motions in mult periods had formed passages for the gas to seeondarily migrate: ③ the area in West Sichuan has the dynamic force for secondary migration; ④there are more and better trap structures in the area;⑤ the above structures is good. Finally. the favouring districts and structures for explorating are pointed out in this paper.
【CateGory Index】： P618.13