Sedimentary facies and palaeogeography of the Zhujiang Formation sequences in eastern Zhujiangkou Basin

With the aid of sequence stratigraphic and sedimentological theories and in integration with core observation, thin section examination, well logs and seismic data, the Zhujiang Formation in eastern Zhujiangkou Basin may b divided into:(1) the siliciclastic depositional system including delta, littoral and shallow marine facies, and (2) carbonate depositional system including open platform, platform-margin and platform foreslope facies. Four third-order sequences have been distinguished for the Zhujiang Formation on the basis of exposure indicators, lithologic association, organic association and well logs, and sedimentary facies and palaeogeographic maps are constructed according to the systems tracts of the third-order sequences or the third-order sequences. The platform-margin and intraplatform reefal (bank) deposits formed during the deposition of the SQ1-HST, SQ2-HST and SQ3 sequences are considered as the favourable zones for hydrocarbon accumulation in the study area.