Study On Reservoir Sedimentology Of Lower Permian In The Xichang Basin, Sichuan

The Xichang Basin is a little basin in the west margin of the Yangzi Block, and it was in the stage of passive plate boundary extending and filling in the Middle Permian . The study of the Middle Permian which is one of the beneficial layers which are explored has a great significance for both theoretic study and oil exploration. Generally, previous studies and studies of sedimentary geology,geophysics,geochemics and paleobiology in the research area allowed me to carry out a further study of the Middle Permian, in terms of the reservoir sedimentology.To be more specifically speaking, this thesis had carefully studied the characteristics of petrology, depositional facies, facies model and the distribution of depositional facies by the means of geology, reservoir sedimentology, lithofacies pleogeography and petrology, with the petrologic, palaeontologic and vestigiofossil, geophysical and geochemical information. The finding that had been reached were as following:Firstly, we studied the rock, paleobiology and vestigiofossil of the Middle Permianin in the Xichang Basin by the means of observing outcrops, micro-pictures of rocks, electron microscopy ,and then we recognized the characteristics of rocks, depositional facies, facies model and the distribution of depositional facies in the research area. We know that there mainly are platform facies and platform edge facies, including six subfacies: plateau tidal flat facies, restricted platform facies, open platform facies, platform edge shallow facies and platform edge reef facies.Secondly, we studied reservoir rocks, reservoir space, reservoir quality and the distribution of reservoir. Then we know that the main reservoir rock is organic reef dolomite, the other reservoir rocks are sparry grain limestone , bioclastic limestone,interclastic limestone; the main reservoir space is emposieu, split, intercrystal emposieu, intergranular emposieu, and the other is intercrystal pore and moldic pore; the reservoir rocks have low quality and uneven distribution.Finally, base on the study of reservoir and depositional facies, we evaluated the quality of the reservoir in the research area by the evaluation criterion of carbonatite reservoir and predicted the favourable blocks.