Objective The Yubei area is located in the mid-east Maigaiti slope of southwestern Tarim Basin,China,with an exploration history of several years.Recent exploration has preliminarily indicated that the Ordovician carbonate formations in this area have some oil and gas potential.Carbonate microfacies provides material basis for reservoir development,seal formation and hydrocarbon Objective The Yubei area is located in the mid-east Maigaiti slope of southwestern Tarim Basin, China, with an exploration history of several years .Recent exploration has preliminarily indicated that the Ordovician carbonate formations in this area have some oil and gas potential .Carbonate microfacies provides material basis for reservoir development, seal formation and hydrocarbon