关键词: 三塘湖盆地, 构造演化, 烃源岩, 成藏关键时刻

Abstract: The Santanghu Basin is a middle-minor scale petroleum basin whose tectonic evolution has been very complex since late Paleozoic. Its evolutional history can be divided into three stages: formation of basement during Carboniferous to early Permian, development during late Permian to Cretaceous and reconstruction since Tertiary. It was an active continent margin in early Carboniferous when ancient Junggar oceanic basin was subducting to north. By the late Carboniferous time a collision occurred between the kazakhstanian plate and the Siberian plate. It was in a tectonic transform phase from collisional compression to post-collisional extension in early Permian. The Basin came into development stage during late Permian to Cretaceous including the extension and fault period of post-orogeny in late Permian, the compression and uplift period at end of Triassic, the extension and depression period from Jurassic to early Cretaceous, and the compression and thrust period at the end of early Cretaceous. During its tectonic evolution, the Santanghu Basin was in extensional setting in late Permian, in which three sets of hydrocarbon source rocks deposited. They are the Lucaogou Formation of upper permian, the Xiaoquangou Group of upper Triassic and Shuixigou Group of the lower-middle Jurassic, which are dominated by dark mudstone. The end of early Cretaceous and the late Eocene are two critical moments of the reservoir generation and accumulation in the Santanghu Basin due to the control of regional tectonic compression. Especially the reconstruction during the Late Cenozoic, which is of far reaching importance for the petroleum can enter into mature oil-generating stage or not.

Key words: Santanghu Basin, tectonoc evolution, hydrocarbon source rocks, critical moment of the reservoir generation and accumulation