论文部分内容阅读
The Songpan-Aba area,similar to those basins on the Yangtze block,following the rifting and separation of the Yangtze block,gradually developed into a passive marginal basin on a passive continent margin in Early Paleozoic,and later,with the Qinling-Qilian oceanic crust subduction and ocean closure,the Caledonides were formed and the foreland basin was superimposed upon.Being influenced by the Paleo-Tethyan extension,intra-continental rifting-margin basins were formed in Late Paleozoic.Following the formation of peripheral orogenic belt,the Upper Triassic again superimposed the foreland basin.The Mesozoic and Cenozoic overprinted the faulted basin,forming the Qinghai-Tibet Plateau domes.Hydrocarbon source rock in the Early Paleozoic passive basin,the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoir- cap combination.Each layer of this area is at the advanced stage of diagenetic evolution,being entered the middle and late diagenetic stages,and anadiagenetic stage.Besides the highly matured Triassic and Permian in Zoigêand Hongyuan,almost all the area is at the early stage of over maturatation, generating much methane.This area has the potential for oil and gas.
The Songpan-Aba area, similar to those basins on the Yangtze block, following the rifting and separation of the Yangtze block, progressive developed into a passive marginal basin on a passive continent margin in Early Paleozoic, and later, with the Qinling-Qilian oceanic crust subduction and ocean closure, the caledonides were formed and the foreland basin was superimposed upon.Being influenced by the Paleo-Tethyan extension, intra-continental rifting-margin basins were formed in Late Paleozoic. Cooling the formation of peripheral orogenic belt, the Upper Triassic again superimposed the foreland basin. Mesozoic and Cenozoic overprinted the faulted basin, forming the Qinghai-Tibet Plateau domes.Hydrocarbon source rock in the Early Paleozoic passive basin, the Upper Paleozoic platform carbonates and the Triassic mudstones comprise the main source-reservoir- cap combination. Each layer of this area is at the advanced stage of diagenetic evolution, being entered the middle and late diagenetic stages , and anadiagenetic stage. Besides the highly matured Triassic and Permian in Zoigê and Hongyuan, almost all the area is at the early stage of over maturatation, generating much methane. This area has the potential for oil and gas.