Several sets of source rocks have developed and experienced multistage thermal evolution in Turpan-Hami basin

a superimposed basin

as a result of long-term basin evolution and multiphase tectonic activity

thus hydrocarbon-generating history is very complicated. Study of the basin's southern structural belt indicates that this area has experienced multiphase tectonic movements and modifications since Late Paleozoic. Structural thermal system and thermal evolution can be divided into five stages

including an extensional rift stage with rapid burial and super-high temperature gradient from Carboniferous to Early Permian; a post-rift depression stage with relatively rapid burial and high temperature gradient during Middle Permian; an intracratonic depression stage with steady subsidence and relatively high temperature gradient from Late Permian to Triassic; a broad sedimentation stage with steady subsidence and relatively low temperature gradient from Jurassic to Cretaceous; and a compressional orogenic stage with relatively quick subsidence and low temperature gradient during Cenozoic. Source rocks in various horizons and regions have different organic maturation and evolutional history. Both source rocks in Permian Lucaogou Formation in Tainan depression and Middle-Upper Triassic Xiaoquangou Formation in Tuokexun depression have experienced two hydrocarbon-generating processes. The reservoir types and hydrocarbon properties in Tainan depression are obviously different from those in Tuokexun depression

due to differences in burial history and hydrocarbon-generating history.