The Shihezi Formation in the northeast Ordos Basin was studied to understand how different types of river deltas filled up over time. In the early stages, braided and meandering river deltas were filled, while in the mature stage, anastomosed river deltas were filled. These deltas provided space for rivers to evolve and for sand to accumulate, creating favorable conditions for reservoir formation. Certain types of distributary channels in the braided river delta were identified as the best for reservoir formation. Similar channels in the meandering river delta and nodes in the anastomosed river delta could also become good reservoirs. The formation of lithologic reservoirs in the Ordos Basin was influenced by the ancient landscape and the filling patterns controlled by changes in base level.