Sequence Stratigraphy Of Carboniferous In Tarim Basin

Tarim basin is the biggest oil-gas basin in internal mainland. It has abundant oil-gas reservoir and bright exploit perspective. With the deepen of explore, its elementary research can't satisfy the need of explore and exploit. The paper regard the whole basin as research object and take the sequence stratigraphy and sedimentary research. The paper constructs Tarim basin Carboniferous sequence stratigraphy framework and sedimentary mode by outcrop,drilling-logging data and theory research. The paper discuss the feature of parasequence, parasequence sets,Depositional system tract and the distribution rule of sedimentary faces,analyze and evaluate the combination of source rock-reservoir-cap rock,thus the advanteged explore region.On the base of research about Tazhong,Bachu and Tabei, Carboniferous sequence stratigraphy research is taken and it is devided into 5 standard third-order sequence (Csq1,Csq2,Csq3,Csq4,Csq5). CsqlandCsq4 are whole I type third-order sequence. Csq2 and Csq3 are II type third-order sequence,transgressive systems tract and highstand system tract are developed. Csq5 is II type third-order sequence, only transgressive systems tract is developed while highstand system tract is denadated.The research of Carboniferous sedimentary system show the type of clastic facies and carbonate facies. It can be concluded that clastic facies consisting of tidal facies, lagoon facies, Fluvial facies, alluvial fan facies and fan delta and carbonate facies including evaporation platform, restrict platform, open platform and ford of platform margin. Totally, Transgressive systems tract mainly develop carbonatite deposition, such as bioclastic limestone interval, standard carbonate interval and Xiaohaizi carbonate interval. But Highstand systems tract mainly presents clastic tidal and fan delta.After the construction of the Carboniferous sequence stratigraphy framework,the paper evaluate source rock-reservoir-cap rock and elect the advanced explore region. After the study of Carboniferous sequence stratigraphy,the paper concludes three main combination of reservoir and cap rock in the sequences framework. The first one combination is Sand shale interval in Carboniferous and Xiaohaizi calcareous rock which is better one. The second one is bioclastic limestone interval and middle-up mudstone interval which is poor one. The third one is Pebbled sandstone interval, Donghe sandstone interval and down mudstone interval which is better one. Good source rock present in Transgressive systems tract of Csq2 and Csq4, and there are two distributions zones for good source rock. The first one is well Hetian 1-well Ma 4 zone, the second one is the west area of south west Tarim basin.