Huang F.X.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation |
Huang F.X.,Petrochina |
Chen H.D.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation |
Chen H.D.,Research Institute of Sedimentary Geology |
And 7 more authors.
Acta Petrologica Sinica
Guided by the idea of "tectonic-controlled basin, basin-controlled sedimentary facies, sedimentary facies-controlled source-reservoir-cap assemblage" and the principle of "process-response", namely that the basin is formed by crust-mantle coupling, plate activation and tectonic movement, and the space-time distribution of the sedimentary sequence and the fácies zone association is formed by the sedimentary and filling processes of basin, while the configuration of sedimentary sequence of different orders, the superimposed pattern of system tract and the space-time association of facies zone are closely related with the sedimentary filling process of basin. On the basis of many research and exploration results of the Middle and Upper Yangtze cratonic basin made by previous research findings, it is thought that further study on sedimentary environment, sequence configuration and the filling process of sedimentary and so on, are significantly important to deepening the understanding and oil and gas resources exploration of the researched area Therefore, relied on the sedimentary response records of the profile configuration of sedimentary sequence, the superimposed pattern of system tract and facies zone association, the sedimentary filling process of basin can be effectively revealed by analyzing the temporal and spatial variation law of these records. Specific technical route is that the tectonic-sequence ( second-order sequence) that indicates the overall characteristics of basin is considered as the basis, the sequence stratigraphy (third-order sequence) that indicates the filling framework of basin is taken as the research unit Meanwhile, the sequence configuration, superimposed modes ( above fourth-order sequence) and the distribution pattern of facies belts are taken as the research objects. Based on the division of the type and evolutionary phase of Middle and Upper Yangtze cratonic basin in Caledonian Period, this paper has analyzed the sedimentary filling process of typical basin, discussed the filling characteristics of sedimentary sequence and its difference and established the sedimentary evolution model in stages. It is found by the study that the Middle and Upper Yangtze craton in Caledonian Period is composed of two sedimentary system tracts including intracraton and craton-margin and the basin undergoes two evolutionary phases that change from extension mechanism to compression mechanism, which are composed of three stages of sedimentary filling processes including rift valley type basin, chasmic basin and depression basin. Generally, the Caledonian cratonic basin under different evolutionary phases or the basin of different types under the same evolutionary phase has different sedimentary responses including sedimentary formation type, sequence configuration and superimposed pattern of system tract, which indicates the distinguishable sedimentary filling characteristics and obviously different controlling factors. In a word, the controlling factors for the filling process of tectonic-sequence are complicated and changeable, which are composed of the structural characteristics of basement, tectonic movement, discordogenic fault, paleohigh, the change of relative sea level, climate change, provenance supply and so on, while the mutual effect and comprehensive influence of these factors are the key to form the special sequence configuration and superimposed pattern for the specific basin in specific period. Besides, the sedimentary model of each phase has inheritance and divergence characteristics in some aspects such as filling background, formation type, distribution law of facies zone, evolutionary process and controlling factors. Especially, the Middle and Upper Yangtze craton in Caledonian is characterized by the framework of uplift and depression, in which the platform edge banks, introplatform dolomite beaches and the salt and gypsumis are of great significance to preservation and accumulation of oil and gas. Source