The hydrocarbon exploration in Tazhong and Gucheng area in Tarim Basin has made great breakthroughs,but the identification of sedimentary system is still based on the mapping of lithofacies and paleogeography on basin scale,lacking the detailed regional research with the constraints of multiple data.Petrological analysis was used to recover the precursor limestone of the Cambrian in Tazhong and Gucheng area.The lower and middle Cambrian in Tazhong area is dominated by mudstone,wackestone and gypsum-bearing wackestone,while the upper Cambrian mainly developed grainstone and wackestone;and the Cambrian in Gucheng area is dominated by wackestone,packstone and grainstone.The reconstruction of the paleo-environment of the Cambrian in Tazhong and Gucheng area by geochemical analysis shows that the sea water was deepening and the salinity and evaporation was decreasing during the deposition of Cambrian.With the guidance of carbonate comprehensive facies model of Wilson,this area has been divided respectively into 3facies,4subfacies and 6mircrofacies.Based on the interpretation of 3Dseismic data,the development and evolution of the reef-beach bodies of platform margin in Gucheng area was described,showing that the reef-beach bodies of four stages migrated towards the basin in progadation.In stagesⅠandⅡreef-beach bodies developed during the transgression process while in stages Ⅲ and Ⅳ reef-beach bodies developed during the regression process,presenting progradation sedimentary style.The migration characteristics analysis of reef-beach bodies and the development character of inner platform deposits show that the reef-beach bodies of Gucheng platform margin had great influence on the inner platform environment.The quick deposition of carbonate in platform margin resulted in the enclosing of inner platform water and the deposition of gypsum-bearing carbonate rocks.The deposits in inner platform and platform margin have good correspondence.
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