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Sequence stratigraphy and petrafades palaeogeography of Carboniferous system in the Tarim basin |
Zhao Xiuqi, Zhang Zhensheng, Li Hongwen |
Geophysical&Geological Research Institute, Bureau of Oil Geophysical Prospecting, Zhuozhou City, Hebei Province, Postcode:072751 |
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Abstract Having analysed seismic,drilling and crop data of Carboniferous system in the Tarirn basin,we divide Carboniferous system into three sedimentary sequences(CⅠ、CⅡ、CⅢ)or eight depositional system tracts(CⅠ1、CⅠ2、CⅠ3、CⅡ1、CⅡ2、CⅡ3、CⅢ1、CⅢ2).In basin fades area,lowstand and transgression depositional system tracts occur quite widely,but ltighstand depositional system tract does not.In plat-forth fades area,transgression and highstand depositional system tracts exist wide1y;lipwever,lowstand depositional system tract is missing.Analysed in sequence stratigraphy, the Carboniferous Tarirn basin was a sea basin where there were subbasins,shelves,depressions and rises.The evolution process of the petrofacies palaeogeograplty consists of three cycles or eight phases,which correspond to sedirnentary sequences or depositional system tracts respectively.The hydrocarbon reservoir may include beach-fades sandrock and carbonatite of biodetritus beach facies in transgression period,sandrock and dolomite of highstand delta facies.The favourable hydrocarbon exploration areas are mid-Tarirn uplift,north-Tarirn slope and mid-west part of Maigaiti slope.
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Received: 15 October 1994
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