Northeastern Sichuan Feixianguan Formation Of Lower Triassic Sedimentary Facies And Their Control Of The Reservoir,

Guided by the theories of carbonate sedimentology, paleontology, stratigraphy, reservoir geology and digenesis, there is an extensive and deep study of formation, rocks,sedimentary fades, essential characteristics of reservoir and the key factors of reservoir of Feixianguan formation in lower Triassic series, northeast Sichuan. Multiple method of point, line and surface, field and indoor, macroanalysis and microanalysis and technology of microscope have been used in the research. It is believed that Northeast Sichuan was locacted in an isolated carbonate platform at nearly Feixianguan period, early Triassic, an isolated carbonate platform in the initial period of Feixianguan succeeded the sedimentary framework of the early period of late Permia and evolved into homogeneous tidal flat-lagoon in the fouth of Feixianguan, based on the research of field profile and indoor, petroleum drilling, regional geologic feature and the existed research achievements. The isolated carbonate platform environment (fades) could be fijrther classified into subenvironments: tidal flat, lagoon, marginal plateform, continental shelf and slope. The type and characteristics of sedimentary fades (sedimentary subfacies and sedimentary microfacies) are explained, a distribution law of the sedimentary fades in vertical and horizontal and a model of the sedimentary are established. Lithology, porosity and permeability feature, the space and pore texture characteristics of reservoir are described. The controlling factors of the reservoir are studied. Regional distribution of reservoir has been predicted on the basis of the above discussed. I and II types of reservoir locate in platform edge oolitic beach of Luojia 2 Well-Po 2 Well, while II and III types of reservoir locate in Platform edge oolitic beach which near lagoon, III, IV types of reservoir develop in the lagoon surrounding the area of Ying 1 Well-Po 3 Well, III type of reservoir develop in the platform edge oolitic beach in the southeast and north of the research area.