Based on field outcrop observations in the north Tarim Basin and thin-section observations of typical drilling wells, we accurately established a sedimentary model and finely characterized the spatiotemporal distribution patterns of high-energy mound and shoal facies. The results show that a carbonate ramp is developed in Xiaoerbulake Formation in Tarim Basin. The types of sedimentary facies include mixed tidal flat, inner-ramp (dolomite-flat, lagoon and shoal), middle-ramp (inner zone, outer zone, microbial mounds, and shoal) and outer ramp-basins. By characterizing the spatiotemporal distribution of sedimentary facies within the isochronous stratigraphic framework, an internal depression and distally steepening carbonate ramp model was established. The high-energy mound and shoal facies deposits with high-quality reservoirs are mainly affected by the original paleogeomorphy and fluctuation of relative sea level. The middle-ramp shoals are developed in Tazhong area, the middle-ramp mounds and shoals are developed in Bachu area and Keping area, and the middle-ramp shoals are developed in the high paleogeomorphy of Lunnan area.

Tarim Basin, Lower Cambrian, Xiaoerbulake Formation, sequence stratigraphic framework, sedimentary facies, sedimentary model