Sequence stratigraphic framework and sedimentary model of Niubao Formation in Lunpola Basin, central Tibet

Based on an integrated investigation of well logging, seismic data, cores and outcrops, the Niubao Formation in the Lunpola Basin was subdivided into one first order sequence, three second order sequences, corresponding to the first, second and third members of Niubao Formation, and seven third order sequences from base to top, namely SQ1, SQ2, SQ3, SQ4, SQ5, SQ6, and SQ7. Two sequence stratigraphic patterns including faulted slope zone and flexure slope break zone were identified within the sequence stratigraphic framework. There are several exploration targets, including fan deltas on the gentle slope of HST and large-scale low stand fans in the slope break zone of LST in the flexure slope break zone, and high stand braided river deltas and large-scale low stand fans in the slope break zone in the faulted slope zone. A sedimentary model was established through the analyses of spatial and temporal distribution of the sequences. Three main sand bodies developed in the Niubao Formation, namely the northern, southwestern and eastern sand bodies, and their distribution was controlled by the slope break zone.