Abstract:

Sedimentation is one of the key controlling factors in the formation of the reef and shoal carbonate reservoirs. This research studied the Lower Triassic Feixianguan shoal reservoir of marginal carbonate platform facies in the Puguang and Yuanba area, northeastern Sichuan Basin. The sedimentation background and its evolution history were studied before the microfacies analyses were conducted. The highfrequency cycles were divided and described based on drilling well data. The controls of stratigraphic sequences on reservoir formation, highfrequency cycles on porosity distribution, relative sea level fluctuation on reservoir heterogeneity, as well as early depositional and diagenetic environment on early porosity formation were discussed.

Key words: sedimentary facies, highfrequency cycles, reservoir formation, Feixianguan Formation, northeastern Sichuan Basin