Characteristics of the Hydrocarbon Accumulation Formed Through the Three Structural Cycles in Tarim Basin
The Tarim Basin was formed through three major extensional-compressional tectonic cycles:Nanhua-Middle Devonian,Late Devonian-Triassic,and Jurassic-Quaternary.This multi-cycle tectonic evolution led to the complexity of the oil and gas accumulation and distribution.In recent years,the ultra-deep layer of the ba-sin has become the key exploration area of oilfield.It is necessary to investigate the hydrocarbon accumulation law of the basin.According to the latest seismic data,drilling data,and oil and gas geological data,we find that the main source rocks of oil and gas accumulation in Tarim Basin are Triassic-Jurassic in the Kuqa area,and the Carboniferous-Permian continental source rocks in southwestern Tarim Basin,the Cambrian marine source rocks in the platform basin area.The development of the source rocks and reservoir-seal assemblages in the basin is controlled by the three major extensional-compressional tectonic cycles of the basin.The develop-ment position of the source rocks determines the development of the four petroleum systems in Tarim Basin,in-cluding the Kuqa piedmont,northern depression,Maigaiti slope,and southwestern Tarim piedmont.The basin has undergone the three major extensional-compressional cycles,and the hydrocarbon accumulation assemblages in the platform basin area,Kuqa foreland and southwestern Tarim foreland are distinct.The Carboniferous gyp-sum mudstone and Silurian-Carboniferous marine sandstone,Ordovician mudstone,and limestone,Middle Cam-brian gypsum salt rock,and Sinian-Cambrian dolomite reservoir-cap assemblages occur in the basin.The Neo-gene-Quaternary mudstone and sandstone,Paleogene gypsum salt layer,Cretaceous sandstone reservoir,Juras-sic mudstone,and Triassic-Jurassic sandstone reservoir-cap assemblage occur in the Kuqa area.The Miocene mudstone-sandstone,Paleogene gypsum-salt layer,and Cretaceous sandstone,Carboniferous-Permian mudstone and carbonate reservoir-cap assemblages are developed in the southwestern Tarim Basin,which constitute the upper,middle,and lower assemblages of the platform basin,Kuqa and southwestern Tarim Basin,respectively.The hydrocarbon expulsion of the source rocks in the basin occurred in late Caledonian,late Hercynian-Indosin-ian and Himalayan,forming three stages of oil and gas filling.Combined with the development characteristics of lithology,fracture,unconformity,and uplift in the key transformation period of Tarim Basin,the three-stage accumulation model of the basin is proposed.
Tarim Basintectonic cyclepetroleum systemreservoir-cap assemblageaccumulation model
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万方数据
维普
