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Study On Sedimentary System And Sequence Stratigraphy Of The Xujiahe Formation Of The Upper Triassic Series In Central And Western Sichuan Basin

Posted on:2010-02-08Degree:MasterType:Thesis
Country:ChinaCandidate:M S FengFull Text:PDF
GTID:2120360278960599Subject:Mineralogy, petrology, ore deposits
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Based on the theories of sedimentology and high-resolution sequence stratigraphy, this paper researchs the sedimentary system, high-resolution sequence stratigraphy, sequence-based lithofacies-paleogeography, reservoir characteristics and reservoir distribution in sequence stratigraphic framework of the Xujiahe Formation of the Upper Triassic in Central and Western Sichuan basin by using geologic, logging and seismic methods.On the basis of previous research, by comprehensively analysing the regional geotectonic setting and sedimentary setting data, observing outcrop and core, and then investigating geological, logging and seismic profile, this paper divids the sedimentary system of the Xujiahe Formation into 3 types of sedimentary system groups, 6 types of sedimentary systems, 17 sedimentary subfacies and 46 sedimentary microfacies. It deeply investigates the characteristics of sedimentary facies, sedimentary subfacies and sedimentary microfacies, and establishs the sedimentary models.On the basis of analysis on seismic sequence, this paper divids the Xujiahe Formation into 4 long-term sequence cycles,10 middle-term sequence cycles,and tens of short-term sequence cycles. It establishs sequence stratigraphic framework of the Xujiahe Formation of the Upper Triassic in study area,and also deeply investigates the characteristics of all levels sequence.The sequence-based lithofacies-paleogeographic maps of the Xujiahe Formation of the Upper Triassic in study area are compiled by choosing middle-term sequence cycles as the isochronous mapping unit. This paper demonstrats in details the characteristics of lithofacies aleogeography and their evolution during different middle-term sequence cycles development from MSC01 to MSC10.The reservoir characteristics of the Xujiahe Formation in study area are investigated by many such scientific means as the casting thin sections observation, scanning electron microscope and physical property analysis. This paper concludes that sedimentary system developed in the Xujiahe Formation reservoir in the study area is dominantly braided river delta. The reservoir sandstone is dominantly underwater distributary channel and mouth bar microfacies of braid river deltas front. Reservoir is developed in the middle-term sequence cycles of MSC02, MSC03, MSC05, MSC06 and MSC09.Favorable reservoir distribution in the study area is forecasted in this paper by combining previous exploration with the study of sedimentary system, sequence stratigraphy and their relationship with reservoir distribution.
Keywords/Search Tags:Central and Western Sichuan basin, Xujiahe Formation, sedimentary system, high-resolution sequence stratigraphy, sequence-based lithofacies-paleogeography
PDF Full Text Request
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