The Lithofacies-paleogeography and Space-time Evolvement of Silurian-Devonian in the Tarim Basin

A great attention has been repaid to the study of the Silurian-Devonian in the Tarim Basin due to the discovery of petroleum in the interval,but there still exists some basic geologic problems which hinder the exploration.Through comprehensive analysis of field section,drilling well and well core,on the basis of detailed strata division and comparison,the Silurian-Devonian was identified three sedimentary system group(including continental facies,marine-continental transition and marine sedimentary system group)in the Tarim Basin,and can be further identified eight sedimentary system.On the basis of the above sedimentary research,combining the identification of well logging and seismic facies.The detailed research on the character and space-time evolvement of the lithofacies-paleogeography of Silurian-Devonian has been carvied out,and the research indicates that in the process of sedimentary evolvement,the character of lithofacies paleogeography is different in each phase,but it is succession.It shows that the dominant facies is shelf sea,shore and tidal-flat in the whole Silurian,and the sedimentary facies zone is South-North zonation,east-west spread;from late Silurian to Devonian the sedimentary environment is shore and tidal-flat,but the sedimentary facies zone is more limited;late Late Devonian the sedimentary environment is shore and tidal-flat,and the sedimentary range is more shorten.The obtain of above research will provide base information for the studying of reservoir regulatities of distribution and petroleum forcasting.