Controls of tectonics on both sedimentary sequences and petroleum systems in Tarim Basin, northwest China

Abstract

Various orders of sequences were recognized in the Tarim Basin from unconformities. Three mega-sequence groups, six mega-sequences, sixteen super-sequences and forty-two sequences were determined from the Sinian to the Quanternary. The mega-sequences and super-sequences were in accordance with the locally tectonic events occurring in both the north and the south margins of the Tarim plate. The global sea level changes only worked to control formations in the tectonically stable periods or in the low order sequences. The sequences had close relationship to the source rocks, reservoirs and cap rocks, and the tectonic events determined the migration, accumulation, and preservation of the hydrocarbon. The three mega-sequence group cycles, including the early cycle-the Sinian-middle Devonian, the middle cycle the upper Devonian-Triassic, and the late cycle-the Jurassic Quaternary, corresponded to three reservoir formation cycles. So, it can be concluded that the local tectonic events controlled both the sequences and the distribution of oil and gas in the Tarim Basin.